Antioxidant Effect of Spirulina (Arthrospira) maxima on Chronic Inflammation Induced by Freund's Complete Adjuvant in Rats

Abstract

One of the major mechanisms in the pathogenesis of chronic inflammation is the excessive production of reactive oxygen and reactive nitrogen species, and therefore, oxidative stress. Spirulina (Arthrospira) maxima has marked antioxidant activity in vivo and in vitro, as well as anti-inflammatory activity in certain experimental models, the latter activity being mediated probably by the antioxidant activity of this cyanobacterium. In the present study, chronic inflammation was induced through injection of Freund's complete adjuvant (CFA) in rats treated daily with Spirulina (Arthrospira) maxima for 2 weeks beginning on day 14. Joint diameter, body temperature, and motor capacity were assessed each week. On days 0 and 28, total and differential leukocyte counts and serum oxidative damage were determined, the latter by assessing lipid peroxidation and protein carbonyl content. At the end of the study, oxidative damage to joints was likewise evaluated. Results show that S. maxima favors increased mobility, as well as body temperature regulation, and a number of circulating leukocytes, lymphocytes, and monocytes in specimens with CFA-induced chronic inflammation and also protects against oxidative damage in joint tissue as well as serum. In conclusion, the protection afforded by S. maxima against development of chronic inflammation is due to its antioxidant activity.

Introduction

Inflammation is an immune system reaction that occurs in vascularized tissue and is caused by physical, chemical, or biological agents, its purpose being to find, isolate, and eliminate pathogenic agents and repair the damaged area. Diverse pathologies are closely related to chronic inflammation as a part of their pathogenesis, among others, rheumatoid arthritis (RA).^1,2 This chronic degenerative autoimmune disorder is present in 2–4% of the world's population. In Mexico, it has an incidence of 0.3% (0.1–0.6%), 59% of this population being women and 41% men.³

One of the most important mechanisms in the pathogenesis of chronic inflammation is the production of reactive oxygen species (ROS) and reactive nitrogen species by activated macrophages.⁴ An increase in the levels of free radicals can compromise the structure and function of various important biomolecules, such as proteins and membrane lipids in joint tissue of RA patients, inducing oxidative stress.⁵ Although the exact cause of RA is unknown, articular disorders have been associated with important increases in the production of ROS, including free radicals such as the superoxide anion, nitric oxide, and their derivatives. Hence, drugs that combat the damage produced by an excess of ROS in joint tissue should be quite useful for impeding the development and progression of articular disorders like RA.⁶

At present, anti-inflammatory and especially antiarthritic treatments are aimed at blockage of inflammatory mediators or inhibition of the cells producing them to control their degenerative effect on joints of RA patients.^7
–9 However, due to the large number of side effects elicited by these pharmaceuticals, patients have increasingly focused their attention on natural remedies.¹⁰

Spirulina, a practically harmless cyanobacterium, has been demonstrated to have marked antioxidant activity in vivo and in vitro. ^11
–13 This is attributed to the synergistic action of its components such as antioxidant pigments, phycobiliproteins, carotenes, vitamins C and E, γ-linolenic acid, and phenolic compounds.^14,15 The antioxidant effect of Spirulina may be responsible for its multiple pharmacological activities, which include antiviral,¹⁶ hypoglycemic,¹⁷ hypolipidemic,¹¹ anticarcinogenic,¹⁸ antianemic,¹⁹ and anti-inflammatory²⁰ properties.

It has been shown that the consumption of Spirulina can prevent different pathologies associated with oxidative stress and inflammation. Previous studies have determined its anti-inflammatory activity in mouse models of chronic inflammation and RA, by evaluating β-glucuronidase in synovial fluid and subplantar edema, as well as diverse enzymes such as aspartate aminotransferase, alanine aminotransferase, and alkaline phosphatase, but have not associated this effect with the above-mentioned antioxidant activity of this cyanobacterium.^20,21 Besides, Spirulina inhibits the activation of the nuclear transcription factor that is activated by ROS and, thereby, also inhibits the expression of cytokines and enzymes like TNF and iNOS, respectively. In this way, cyanobacteria can counter the onset of inflammatory disorders and attenuate their progression.²² Indeed, C-phycocyanin, which is the main antioxidant compound of Spirulina, has been proposed as the principal anti-inflammatory and antiarthritic agent of cyanobacteria, since it exerts an important anti-inflammatory effect through different mechanisms of action. One such mechanism is ROS scavenging.²³ However, this anti-inflammatory effect has not been associated with the antioxidant activity of the complete cyanobacteria in a model of chronic inflammation. Hence, the objective of the present study was to examine whether or not the anti-inflammatory activity of Spirulina is related to its antioxidant properties, using a model of chronic inflammation that resembles RA.

Materials and Methods

Specimens

Female Sprague-Dawley rats (90–100 g body weight) obtained from the BIRMEX research animal resource facility (Laboratorios de Biológicos y Reactivos de México, Mexico DF) were acclimated for 7 days, with 12-h light/12-h dark periods, temperature 25°C±2°C, 55–80% humidity, and food (Lab Rodent Chow) and water provided ad libitum. Handling of specimens was done according to the policies of the U.S. National Institutes of Health and the official Mexican norm (NOM-062-ZOO-1999) regarding the care and use of laboratory animals.^24,25

Reagents

All reagents were purchased from Sigma-Aldrich (St. Louis, MO, USA).

Procurement and culturing of Spirulina maxima

S. maxima was obtained from the Plant Physiology Laboratory of the Department of Biology (Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, ENCB-IPN) and was subsequently cultured in a photoreactor, adding the Zarrouk culture medium and a micronutrient solution as described by Silveira et al.²⁶

Experimental design

The chronic inflammation model proposed by Helyes et al.²⁷ was used. Specimens were randomly assigned to one of the six groups (n=8): (1) negative control; (2) Freund's complete adjuvant (CFA) control; (3) phenylbutazone (PB); (4) S. maxima (SP); (5) CFA+PB; and (6) CFA+SP. Chronic inflammation was induced by subcutaneous injection of 300 μL of a 1:1 emulsion of phosphate-buffered saline (PBS) pH 7.3 and CFA (1 mg inactivated Mycobacterium tuberculosis per mL malonate) at the base of the tail. Negative control specimens were injected 300 μL PBS only. After 14 days of CFA injection, daily treatment with PB or SP was initiated intragastrically at doses of 100 and 800 mg/kg, respectively, for 2 weeks. Untreated specimens were administered the vehicle only. Injection of CFA or PBS was taken as day 0 of the study. On days 0, 7, 14, 21, and 28, the joint diameter, body temperature, and motor capacity were evaluated. Total and differential leukocyte counts as well as serum oxidative damage by assessment of lipid peroxidation (LPO) and protein carbonyl content (PCC) were evaluated on days 0 and 28. At the end of the study, specimens were sacrificed and oxidative damage to wrist and ankle joints was determined.

Evaluation of joint inflammation and body temperature

Chronic inflammation in the wrist and ankle joints of each specimen was measured with a digital caliper, and results were expressed as the increase in joint diameter in mm.²¹ The rectal temperature was taken and recorded in degrees centigrade.

Determination of motor capacity

Motor capacity was evaluated by the open field test (OFT) during the last darkness period using a 50×50 cm arena subdivided into 5×5 cm squares. Each specimen was placed in the center of the field and the number of crossings made during 5 min was recorded. The field was wiped clean with 5% acetic acid after each measurement.²⁸

Total and differential leukocyte counts

Blood samples were obtained by retro-orbital puncture using EDTA as the anticoagulant, and blood smears were prepared and stained with Wright's procedure for examination in the microscope. The total number of leukocytes was counted, recording also the number of monocytes and lymphocytes.

Oxidative damage

Blood samples were centrifuged at 1,500×g for 15 min to obtain serum. Specimens were euthanized in an ether-saturated chamber and joint tissue was removed from the wrists and ankles in an ice bath. Tissue samples 500 mg in weight were homogenized in 2 mL PBS at pH 7.3. Then, 1 mL of each (homogenate or serum) sample was centrifuged at 10,500×g and 4°C for 15 min and the total protein content was determined in the supernatants. LPO and PCC were evaluated in uncentrifuged homogenate or serum samples. The total protein content was determined by Bradford's method²⁹ and was used to express results.

Determination of LPO

LPO was evaluated by assessing the levels of thiobarbituric acid reactive substances (TBARS). To 500 μL of homogenate or 100 μL of serum was added 2 mL TBARS reagent (16% trichloroacetic acid [TCA], 0.5% thiobarbituric acid, and 0.3 N HCl). The samples were incubated at boiling for 15 min, then placed in an ice bath for 10 min, and centrifuged at 1,000×g and 4°C for 10 min. Absorbance was read at 535 nm. The malondialdehyde (MDA) content was determined using the molar extinction coefficient (MEC) of 1.56×10⁵ M⁻¹ cm⁻¹ and results were expressed as μmol or nmol MDA/mg protein/g tissue or mL serum.³⁰

Protein carbonyl content

To 300 μL of homogenate or 100 μL of serum was added 300 μL of 20% TCA, and the samples were subsequently processed as described elsewere.³¹ Readings were done at 360 nm. PCC was determined using the MEC of 21,000 M⁻¹ cm⁻¹ and results were expressed as μmol or nmol reactive carbonyls (C=O)/mg protein/g tissue or mL serum.

Statistical analysis

The results obtained for markers of general toxicity, leukocyte counts, and oxidative damage parameters in serum were analyzed by two-way repeated measures analysis of variance (ANOVA), while oxidative damage results obtained from joint tissue were subjected to ANOVA on ranks (P<.05). Differences between means were determined with the Student–Newman–Keuls post hoc test. SigmaStat v3.5 was used throughout.

RESULTS

No significant increase in joint diameter occurred in CFA-immunized specimens compared to the negative control group, which indicates that at the macroscopic level, neither edema nor inflammation was developed (data not shown).

Regarding body temperature, hyperthermia was observed in the group injected with the phlogistic agent only (P<.05) compared to the control group. However, in PB- or SP-treated groups, this increase was prevented and normal values were attained (Table 1).

Table 1.

Changes in Body Temperature and Motor Capacity in Specimens with Chronic Inflammation Treated with Spirulina maxima (n=8)

Treatment	Day	Body temperature (°C)	Mobility (crossings/5 min)
Negative control (PBS)	0	37.12±0.15	129.8±3.35
	7	38.1±0.29^•	131±21.47
	14	37.64±0.41	144.8±11.80
	21	37.4±0.18^*	100.8±12.72^• ^* ^▲
	28	37.1±0.37^*	143.6±13.67
Positive control (CFA)	0	37.62±0.18	147±5.24
	7	37.88±0.2	125.6±10.41
	14	38.42±0.22^{a •}	95.4±4.50^{a •} ^*
	21	37.9±0.13	88.4±9.65^• ^*
	28	38.38±0.28^{a •}	100.8±19.58^{a •} ^*
PB 100 mg/kg	0	37.68±0.17	122±1.41
	7	37.4±0.17	126±1.41
	14	37.1±0.18	131.2±0.86
	21	36.86±0.30^•	123.6±2.20
	28	37.8±0.23^{a ▲ ♦}	117.6±1.69
SP 800 mg/kg	0	37.44±0.08	134.4±5.64
	7	37.66±0.18	126±2.00
	14	37.3±0.15	132.6±1.72
	21	37.28±0.14	135.2±2.00^a
	28	37.36±0.23	120±2.16
CFA+PB 100 mg/kg	0	36.6±0.14	114.6±14.76
	7	37.34±0.09^{a •}	112.6±10.38
	14	37.54±0.08^{b •}	99.4±7.82^a
	21	37.32±0.06^•	84±5.03^• ^*
	28	36.68±0.14^{b *} ^{▲ ♦}	104.6±1.63^a
CFA+SP 800 mg/kg	0	37.1±0.07	137±2.36
	7	37.42±0.10	120.4±1.93
	14	37.24±0.12^b	101.2±3.03^{a •}
	21	36.56±0.05^{a b c} ^* ^▲	114.6±2.13^c
	28	36.56±0.06^{b *} ^▲	124.2±1.98^b

Values are the mean±SE. Two-way repeated measures ANOVA, SNK post hoc test (P≤.05).

Versus negative control.

Versus positive control.

Versus CFA+FB.

•

Versus d0.

Versus d7.

▲

Versus d14.

♦

Versus d21.

PBS, phosphate-buffered saline; CFA, Freund's complete adjuvant; SE, standard error; ANOVA, analysis of variance; SNK, Student–Newman–Keuls.

In the OFT conducted to evaluate motor capacity, both untreated and PB-treated CFA-immunized rats showed a significant loss of mobility on days 14 and 28 compared to negative control specimens (P<.05). SP-treated CFA-immunized rats had significantly increased mobility on day 28 in comparison to the positive control group, matching even negative control group values (Table 1).

On the other hand, injection of CFA resulted in the development of leukocytosis on day 28 by comparison to the negative control group, while specimens treated with CFA+PB or CFA+SP evidenced a significant reduction of this condition compared to the positive control group, although normal values were not recovered with either treatment. Furthermore, differential staining revealed monocytosis and lymphocytosis in the positive control group on day 28 by comparison with the negative control group. A significant reduction in both conditions compared to the positive control group occurred on day 28 in groups treated with CFA+PB or CFA+SP; however, treatment with the pharmaceutical agent was more effective (P<.05) (Table 2).

Table 2.

Total Leukocyte Count and Differential (Monocytes and Lymphocytes) Count in Blood of Specimens with Chronic Inflammation Treated with Spirulina maxima (n=8)

Treatment	Day	Total leukocytes (cells/mm³)	Monocytes (cells/mm³)	Lymphocytes (cells/mm³)
Negative control (PBS)	0	2510±164.99	490.24±95.44	14.88±9.42
	28	3258.8±286.93	865.20±79.36	32.49±9.60
Positive control (CFA)	0	1716±149.85	198.2±44.05	3.96±3.96
	28	10030.8±303.58^{a •}	4189.60±137.47^{a •}	3470.04±172.45^{a •}
PB 100 mg/kg	0	1399±160.53	227.02±13.28	2.78±2.78
	28	1211±172.23^a	668.23±8.77	7.3±2.9
SP 800 mg/kg	0	2640±188.40	553.76±63.88	4.64±4.64
	28	3811.6±245.63	946.06±81.06	16.53±10.13
CFA+PB 100 mg/kg	0	2433.6±72.02	736.99±38.86	83.23±15.31
	28	7960±444.52^{a b •}	1789.2±137.32^{a b •}	398±94.71^{a b •}
CFA+SP 800 mg/kg	0	2662±144.77	1021.52±52.37	128.58±15.91
	28	7265±497.21^{a b •}	2935.6±147.66^{a b c •}	1115.35±173.45^{a b c •}

Values are the mean±SE. Two-way repeated measures ANOVA, SNK post hoc test (P<.05).

Versus negative control.

Versus positive control.

Versus CFA+PB.

•

Versus d0.

Regarding oxidative damage, both serum proteins and lipids were affected in all groups in which chronic inflammation was induced (P<.05) (Table 3). However, administration of PB or SP prevented LPO totally and protein oxidation partially since, despite the fact that these treatments induced a decrease in the latter biomarker (P<.05), normal PCC values were not recovered and a significant difference was nevertheless maintained with respect to the control group specimens.

Table 3.

Oxidative Stress Biomarkers in Joint Tissue and Serum of Specimens with Chronic Inflammation Treated with Spirulina maxima (n=8)

		Serum		Joint tissue
Treatment	Day	PCC (nmol carbonyl/mL)	LPO (nmol MDA/mL)	PCC (μmol carbonyl/g)	LPO (μmol MDA/g)
Negative control (PBS)	0	202.47±22.49	35.14±3.64
	28	172.83±25.30	25.97±3.17	1.09±0.19	0.68±0.15
Positive control (CFA)	0	259.70±11.35	32.05±0.69
	28	706.18±71.52^{a •}	57.97±6.52^{a •}	7.53±0.96^a	2.07±0.26^a
PB 100 mg/kg	0	288.55±17.60	21.78±1.69
	28	162.78±5^•	15.84±0.85	1.19±0.03	0.48±0.01
SP 800 mg/kg	0	127.66±30.60	10.47±1.42
	28	124.90±2	11.33±1.73	0.53±0.05^a	0.24±0.004^a
CFA+PB 100 mg/kg	0	297.71±11.43	24.69±13.32
	28	392.61±41.66^{a b •}	19.33±0.94^b	2.63±0.25^{a b}	2.86±1.07^a
CFA+SP 800 mg/kg	0	384.03±53.95	29.39±4.68
	28	274.84±11.91^{a b c •}	34.75±3.37^b	2.39±0.16^{a b}	0.5±0.06^{b c}

Values are the mean±SE. Two-way repeated measures ANOVA (serum) and ANOVA on ranks (joint tissue), SNK post hoc test (P<.05).

Versus negative control.

Versus positive control.

Versus CFA+PB.

•

Versus d0.

PCC, protein carbonyl content; LPO, lipid peroxidation.

Joint tissue of CFA-immunized rats showed a significant increase in both PCC and LPO in comparison to negative control specimens. CFA-immunized groups that were subsequently treated with PB or SP evidenced a significant reduction in PCC compared to the positive control group (Table 3). LPO decreased (P<.05) in CFA-immunized groups treated with PB or SP compared to the positive control group, and treatment was more effective with the cyanobacterium than with the pharmaceutical.

Discussion

RA is a chronic autoimmune disorder characterized by inflammation of the joints, in which joint deformation, loss of mobility, and eventually, bone resorption may occur. Its diverse manifestations at the cellular and molecular levels include inflammation of the synovial membrane, increased leukocyte (lymphocyte and macrophage) infiltration into the synovial space, release of lysosomal enzymes, and overexpression of proinflammatory cytokines.³²

Free radicals act as immunostimulators of the inflammatory process, since they serve as chemoattractors for immunocompetent cells, bringing lymphocytes to the site of damage during the late or chronic stage of the immune response. Additionally, free radicals stimulate immunocompetent cells to generate higher levels of proinflammatory mediators, because oxidative stress induces the transcription of numerous genes that code for the synthesis of proinflammatory mediators or for the enzymes that generate such mediators.³³ An increase in ROS leads to lysis of the membranes of the cells adjacent to the site of damage through oxidative processes like lipoperoxidation, the latter of which generates not only lipidic radicals but also the release of arachidonic acid. In this way, high levels of ROS stimulate the production of phospholipase 2A and later inducible cyclooxygenase (COX-2), triggering the generation of more inflammatory mediators, including prostaglandins (PEG2) and leukotrienes, thus exacerbating chronic inflammation.³⁴

The most commonly used animal experimental models make use of CFA, which induces edematous inflammation of the joints, leukocytic infiltration, increased proinflammatory cytokines, hyperthermia, loss of body mass, reduced mobility, hyperalgesia, and oxidative stress.³⁵

Regarding body temperature, CFA-immunized rats showed hyperthermia both during and at the end of the study. This is in agreement with studies, which have demonstrated that the presence of cell components such as cell wall lipopolysaccharides of certain bacteria (e.g., M. tuberculosis) induces overproduction by macrophages of IL-1β, IL-6, and TNF-α, which act as pyrogens at the affected site or at a systemic level.^36,37 Specimens injected with CFA and treated with SP showed reduced body temperature in comparison to the positive control group. This is probably due to the inhibition of a temperature-regulating cytokine³⁸ or to the arachidonic acid pathway being disabled by suppression of the enzyme COX-2 and, therefore, impairment also of prostaglandin synthesis,²³ as a result of nutritional components and algal pigments such as phycocyanin and γ-linolenic acid.

Similarly, specimens with chronic inflammation showed reduced motor capacity beginning on day 7 and up to the end of the study. This is consistent with a study which, using a 42-day model of CFA-induced monoarthritis, found that the motor activity decreased on days 3–42, mostly as a result of allodynia, while treatment with various Curcuma zedoaria extracts induced increased mobility from day 14 to the end of the experiment.³⁹ In the present study, specimens with chronic inflammation that were treated with SP showed increased mobility at the end of the experiment, perhaps due to inhibition of the allodynia induced in chronic inflammation conditions.⁴⁰ The potential mechanism of pain attenuation may be inhibition of proinflammatory cytokines such as IL-1β and TNF-α ⁴¹ by components present in the cyanobacterium such as long-chain unsaturated fatty acids and the pigments that make up the phycobilisome.⁴²

Macrophage activation is a major characteristic of the inflammatory process. These cells release hydrolytic enzymes and ROS,⁴³ the excessive production of which gives rise to chronic disorders such as RA since the constant action of these species—particularly O₂ ^•−—elicits wear in the connective tissue of body joints.⁵

The model of CFA-induced inflammation is mediated mainly by neutrophils in the acute phase and T lymphocytes in the chronic stage, and in both cases, monocytes/macrophages have an active role. In the present study, untreated CFA-immunized specimens developed leukocytosis on day 28, especially of the monocytic and lymphocytic series. These results are consistent with a study that found lymphocyte values below those of the control group in the acute phase but above them on days 25 and 28, events that are characteristic of chronic inflammation.⁴⁴ On the other hand, treatment with SP decreased the total leukocyte count, particularly with regard to monocytes and lymphocytes. This reduction is indicative of the fact that chemoattraction and cellular differentiation processes were modified by the alga during the development of CFA-induced inflammation, perhaps due to the suppression of proinflammatory cytokines such as TNF-α, IL-1β, and IL-6,^23,45,46 these being the major signaling agents of the immune process since they act as chemoattractants for macrophages, aiding leukocytic infiltration of the affected site^23,47 and also favoring T-lymphocyte differentiation and maturation.^47,48 This has been confirmed by a study which shows that, when the IL-7 receptor is suppressed, there is inhibition of joint inflammation and cartilage destruction combined with reduced chemoattraction of T lymphocytes into the synovial space, and therefore, a decrease in the levels of cytokines induced by this type of cell.⁴⁹

The anti-inflammatory activity of Spirulina is thought to be due, in large part, to a complex of phycobiliproteins known as the phycobilisome and made up of erythrophycocyanin, allophycocyanin, and C-phycocyanin. To the latter are attributed multiple pharmacological activities associated with free radical inhibition. A carrageenan-induced hyperalgesia model has revealed that C-phycocyanin by itself has anti-inflammatory activity since it reduced TNF-α levels and myeloperoxidase activity, selectively inhibiting key enzymes of the acute inflammatory process such as COX-2 and iNOS.³⁸

In a chronic inflammatory process such as RA, the antioxidant defense system of the body is compromised. There is a decrease in reduced glutathione (GSH) levels as well as in the activity of antioxidant enzymes—superoxide dismutase (SOD), catalase, and glutathione peroxidase—and therefore increased LPO, suggesting increased oxidative damage induced at the joint level and detected at the system level.^50
–52

In the present study, high PCC and LPO values were recorded in both tissue and serum of CFA-immunized specimens. The oxidative damage detected in serum is indicative of the fact that the inflammatory process has entered the chronic stage, in which the effect is no longer local but rather systemic and exacerbated. Regarding joint tissue, both PCC and LPO increased in CFA-immunized specimens, suggesting marked oxidative damage. These results are consistent with those obtained in a CFA-induced monoarthritis model, in which LPO was observed to increase in arthritic specimens and the body was no longer able to offset the damage with the help of endogenous antioxidants.⁵¹

In this sense, in chronic inflammatory conditions, reduction in SOD levels and activity has been confirmed, since high TNF-α levels inhibit the expression of two major isoforms of this enzyme (cytoplasmic SOD1 and extracellular SOD3) in both rodents and humans,⁶ which may explain the inability of organisms to offset oxidative damage. On the other hand, a significant reduction in PCC and LPO occurred in both serum and joint tissue of SP-treated specimens, probably due to increased antioxidant enzyme activity⁵³ and the action of algal components. The latter include unsaturated fatty acids such as γ-linolenic acid,^54

–57 cysteine,⁴⁵ a precursor of GSH, and C-phycocyanin, which is able to inhibit OH^• and alkoxyl radicals and decreases LPO of the liver microsomal fraction.²³ Besides the well-known activity of Spirulina as well as phycocyanin as direct scavengers of free radicals and ROS, it has been demonstrated that phycocyanin and phycocyanobilin (both being biliproteins contained in cyanobacteria) also act to regulate enzymatic systems of immunocompetent cells. One such enzymatic system is NADPH oxidase, which generates both free radicals and ROS during inflammation.^58,59

In conclusion, the protection afforded by S. maxima against the development of chronic inflammation is due to its antioxidant activity.

Footnotes

Acknowledgments

This study was supported, in part, by Secretaría de Investigación y Posgrado-IPN funds (Project no. 20121433). G.A.G.R. is funded by the M.C. Grant No. 246646 of CONACyT. M.G.M. and G.A.C.C. are fellows of the EDI and COFAA/IPN Programs. E.M.G. is fellow of the EDD and COFAA/IPN Programs.

Author Disclosure Statement

No competing financial interests exist.

References

Koharyova

, Kollarova

: Oxidative stress and thioredoxin system. Gen Physiol Biophys, 2008; 27:71–84.

Lonkar

, Dedon

: Reactive species and DNA damage in chronic inflammation: Reconciling chemical mechanisms and biological fates. Int J Cancer, 2011; 128:1999–2009.

Gonzalez-Lopez

, Morales-Romero

, Vazquez-Villegas

, Villa-Manzano

, Rocha-Muñóz

, Barragan-Enriquez

, Celis

, Cabrera-Pivaral

, Gamez-Nava

: Factors influencing sick leave episodes in Mexican workers with rheumatoid arthritis and its impact on working days lost. Rheumatol Int, 2012; 33:561–569.

Griffiths

: Is the generation of neo-antigenic determinants by free radicals central to the development of autoimmune rheumatoid disease?. Autoimmun Rev, 2008; 7:544–549.

Hitchon

, Gabalawy

: Oxidation in rheumatoid arthritis. Arthritis Res Ther, 2004; 6:265–278.

Afoso

, Champy

, Mitrovic

, Collin

, Lomri

: Reactive oxygen species and superoxide dismutases: Role in joint diseases. Joint Bone Spine, 2007; 74:324–329.

Covelli

, Sarzi-Puttini

, Atzeni

, Macchioni

: Safety of rituximab in rheumatoid arthritis. Reumatismo, 2010; 62:101–106.

Scott

, Wolfe

, Huizinga

TWJ

: Rheumatoid arthritis. Lancet, 2010; 376:1094–1108.

Agarwal

: Biologic agents in rheumatoid arthritis: An update for managed care professionals. J Manag Care Pharm, 2011; 17:14–18.

10.

Ventura-Ríos

, Bañuelos-Ramírez

, Hernández-Quiroz

, Robles-San Román

, Irazoque-Palazuelos

, Goycochea-Robles

: Terapia biológica: Sobrevida y seguridad en padecimientos reumáticos. Resultados del Registro Nacional Biobadamex 1.0. Reumatol Clin, 2012; 8:189–194.

11.

Torres-Durán

, Miranda-Zamora

, Paredes-Carbajal

, Mascher

, Diaz-Zagoya

, Juárez-Oropeza

: Spirulina maxima prevents induction of fatty liver by carbon tetrachloride in the rat. Biochem Mol Bio Int, 1998; 44:768–793.

12.

Sharma

, Sharma

, Kumar

: Evaluation of protective efficacy of Spirulina fusiformis against mercury-induced nephrotoxicity in Swiss albino mice. Food Chem Toxicol, 2007; 45:879–887.

13.

Ponce-Canchihuamán

, Pérez-Méndez

, Hernández-Muñoz

, Torres-Durán

, Juárez-Oropeza

: Protective effects of Spirulina maxima on hyperlipidemia and oxidative-stress induced by lead acetate in the liver and kidney. Lipids Health Dis (Online) published March 31, 2010, 10.1186/1476-511X-9-35.

14.

Mazo

, Gmoshinski

, Zilova

: Microalgae Spirulina in human nutrition. Vopr Pitan, 2004; 73:45–53.

15.

Batista

, Gouveia

, Bandarra

, Franco

, Raymundo

: Comparison of microalgal biomass profiles as novel functional ingredient for food products. Algal Res, 2013; 2:164–173.

16.

Lee

, Srisomporn

, Hayashi

, Tanaka

, Sankawa

, Hayashi

: Effects of structural modification of calcium spirulan, a sulfated polysaccharide from Spirulina platensis on antiviral activity. Chem Pharm Bull, 2001; 49:108–110.

17.

Joventino

, Alves

, Neves

, Pinheiro-Joventino

, Leal

, Neves

, Ferreira

, Brito

, Viana

: The microalga Spirulina platensis presents anti-inflammatory action as well as hypoglycemic and hypolipidemic properties in diabetic rats. J Complement Integr Med (Online) published August 10, 2012, 10.1515/1553-3840.1534.

18.

Mittal

, Kumar

, Banerjee

, Rao

, Kumar

: Modulatory potential of Spirulina fusiformis on carcinogen metabolizing enzymes in Swiss albino mice. Phytother Res, 1999; 13:111–114.

19.

Simsek

, Karadeniz

, Kalkan

, Keles

, Unal

: Spirulina platensis feeding inhibited the anemia and leucopenia-induced lead and cadmium in rats. J Hazard Mater, 2009; 164:1304–1309.

20.

Remirez

, González

, Merino

, Rodríguez

, Ancheta

: Inhibitory effects of Spirulina in Zymosan-induced arthritis in mice. Mediators Inflamm, 2002; 11:75–79.

21.

Rasool

, Sabina

, Lavanya

: Anti-inflammatory effect of Spirulina fusiformis on adjuvant-induced arthritis in mice. Biol Pharm Bull, 2006; 29:2483–2487.

22.

Mahendra

, Mahendra

, Muthu

, John

, Romanos

: Clinical effects of subgingivally delivered Spirulina gel in chronic periodontitis cases: A placebo controlled clinical trial. J Clin Diagn Res, 2013; 7:2330–2333.

23.

Romay

, Gonzalez

, Ledon

, Remirez

, Rimbau

: C-phycocyanin: A biliprotein with antioxidant, anti-inflammatory and neuroprotective effects. Curr Protein Pept Sci, 2003; 4:207–216.

24.

National Institutes of Health USA. Public Health Service Policy on Humane Care and Use of Laboratory Animals. 2002.

25.

Norma Oficial Mexicana NOM-062-ZOO-1999: Especificaciones técnicas para la producción, cuidado y uso de los animales de laboratorio.

26.

Silveira

, Burkert

JFM

, Costa

JAV

, Burkert

CAV

, Kalil

: Optimization of phycocyanin extraction from Spirulina platensis using factorial design. Bioresour Technol, 2007; 98:1629–1634.

27.

Helyes

, Szabo

, Nemeth

, Jakab

, Pinter

, Banvolgyi

, Kereskai

, Kéri

, Szolcsanyi

: Antiinflammatory and analgesic effects of somatostatin released from capsaicin-sensitive sensory nerve terminals in a Freund's adjuvant induced chronic arthritis model in the rat. Arthritis Rheum, 2004; 50:1677–1685.

28.

Lozano-Hernández

, Rodríguez-Landa

, Hernández-Figueroa

, Saavedra

, Ramos-Morales

, Cruz-Sanchez

: Antidepresssant-like effects of two commercially available products of Hypericum perforatum in the forced swim test: A long-term study. J Med Plants Res, 2010; 4:131–137.

29.

Bradford

: A rapid and sensitive method for the quantification of microgram quantities of protein utilizing the principle of protein-dye binding. Anal Biochem, 1976; 72:248–254.

30.

Buege

, Aust

: Microsomal lipid peroxidation. Methods Enzymol, 1978; 52:302–310.

31.

Parvez

, Raisuddin

: Protein carbonyls: Novel biomarkers of exposure to oxidative stress-inducing pesticides in freshwater fish Channa punctata (Bloch). Environ Toxicol Pharmacol, 2005; 20:112–117.

32.

Torres

, Torres

, Mendoza

, Ramírez

: Assessment of nutritional status in a Mexican population of adult patients with rheumatoid arthritis. Nutr Hosp, 2009; 24:233–238.

33.

Gershwin

, Belay

: Spirulina in Human Nutrition and Health. Third Edition, CRC Press, New York, 2007.

34.

Mapp

, Grootveld

, Blake

: Hypoxia, oxidative stress and rheumatoid arthritis. Br Med Bull, 1995; 51:419–436.

35.

Puig

, Ferreiro

, Castaño

, Clara

: Pathophysiology, treatment and experimental models of rheumatoid arthritis. Rev Cub Farm, 2011; 45:297–308.

36.

Lee

, Zhong

, Mace

, Repasky

: Elevation in body temperature to fever range enhances and prolongs subsequent responsiveness of macrophages to endotoxin challenge. PLoS One (Online) published January 10, 2012, 10.1371/journal.pone.0030077.

37.

Conti

, Tabarean

, Andrei

, Bartfai

: Cytokines and fever. Front Biosci, 2004; 9:1433–1449.

38.

Shih

, Cheng

, Wong

, Kuo

, Chou

: Anti-inflammatory and antihyperalgesic activity of C-phycocyanin. Anesth Analg, 2009; 108:1303–1310.

39.

Kaushik

, Jalalpure

: Effect of Curcuma zedoaria Rosc root extracts on behavioral and radiology changes in arthritic rats. J Adv Pharm Tech Res, 2011; 2:170–176.

40.

Otterness

, Bliven

, Milici

: Changes in mobility of the golden hamster with induction of an IL-l-induced arthritis. Mediators Inflamm, 1994; 3:199–204.

41.

Hess

, Axmann

, Rech

, Finzel

, Heindl

, Kreitz

, Sergeeva

, Saake

, Garcia

, Kollias

, Straub

, Sporns

, Doerfler

, Brune

, Schett

: Blockade of TNF-α rapidly inhibits pain responses in the central nervous system. Proc Natl Acad Sci USA, 2011; 108:3731–3736.

42.

Deng

, Chow

: Hypolipidemic, antioxidant and antiinflammatory activities of microalgae Spirulina . Cardiovasc Ther, 2010; 28:33–45.

43.

Johansson

, Hansson

, Nandakumar

, Backlund

, Holmdahl

: IL-10-deficient B10.Q mice develop more severe collagen-induced arthritis, but are protected from arthritis induced with anti-type II collagen antibodies. J Immunol, 2001; 167:3505–3512.

44.

Franch

, Castellote

, Castell

: Blood lymphocyte subsets in rats with adjuvant arthritis. Ann Rheum Dis, 1994; 53:461–466.

45.

Belay

: The potential application of Spirulina (Arthrospira) as a nutritional and therapeutic supplement in health management. JANA, 2002; 5:27–48.

46.

Kumar

, Kumar

, Singh

: Immunomodulatory effect of dietary Spirulina platensis in type II collagen induced arthritis in mice. RJPBCS, 2010; 1:877–885.

47.

Rasool

, Sabina

: Appraisal of immunomodulatory potential of Spirulina fusiformis: An in vivo and in vitro study. J Nat Med, 2009; 63:169–175.

48.

Ravi

, Lata De

, Azharuddin

, Solomon

: The beneficial effects of Spirulina focus on its immunomodulatory and antioxidant properties. J Diet Suppl, 2010; 2:73–83.

49.

Hartgring

SAY

, Willis

, Alcorn

, Nelson

, Bijlsma

JWJ

, Lafeber

FPJG

, van Roon

JAG

: Blockade of the interleukin-7 receptor inhibits collagen-induced arthritis and is associated with reduction of T cell activity and proinflammatory mediators. Arthritis Rheum, 2010; 62:2716–2725.

50.

Jaswal

, Mehta

, Sood

, Kaur

: Antioxidant status in rheumatoid arthritis and role of antioxidant therapy. Clin Chim Acta, 200; 338:123–129.

51.

Kumar

, Roy

: Calotropis procera latex extract affords protection against inflammation and oxidative stress in Freund's complete adjuvant-induced monoarthritis in rats. Mediators Inflamm (Online) published March 19, 2007, 10.1155/2007/47523.

52.

Siems

, Bresgen

, Brenke

, Siems

, Kitzing

, Harting

, Eckl

: Pain and mobility improvement and MDA plasma levels in degenerative osteoarthritis, low back pain, and rheumatoid arthritis after infrared-A irradiation. Acta Biochim Pol, 2010; 57:313–319.

53.

Kuriakose

, Kurup

: Antioxidant and antihepatotoxic effect of Spirulina laxissima against carbon tetrachloride induced hepatotoxicity in rats. Food Funct, 2011; 2:190–196.

54.

Furse

, Rossetti

, Zurier

: Gamma linolenic acid, an unsaturated fatty acid with anti-inflammatory properties, blocks amplification of IL-1b production by human monocytes. J Immunol, 2001; 167:490–496.

55.

Frenoux

JMR

, Prost

, Belleville

, Prost

: A polyunsaturated fatty acid diet lowers blood pressure and improves antioxidant status in spontaneously hypertensive rats. J Nutr, 2001; 131:39–45.

56.

Olveira

, Olveira

, Acosta

, Espildora

, Garrido-Sanchez

, Garcia-Escobar

, Rojo-Martinez

, Gonzalo

, Soriguer

: Fatty acid supplementation improves respiratory, inflammatory and nutritional parameters in adults with cystic fibrosis. Arch Bronconeumol, 2010; 46:70–77.

57.

Olendzki

, Leung

, Van Buskirk

, Reed

, Zurier

: Treatment of rheumatoid arthritis with marine and botanical oils: Influence on serum lipids. Evid Based Complement Alternat Med (Online) published October 9, 2011, 10.1155/2011/827286.

58.

Zheng

, Inoguchi

, Sasaki

, Maeda

, McCarty

, Fuiji

, Ikeda

, Kobayashi

, Sonoda

, Takayanagi

: Phycocyanin and phycocyanobilin from Spirulina platensis protect against diabetic nephropathy by inhibiting oxidative stress. Am J Physiol Regul Integr Comp Physiol, 2013; 304:R110–R120.

59.

McCarty

: Perspective clinical potential of Spirulina as a source of phycocyanobilin. J Med Food, 2007; 10:566–570.