Pathology of B a Deficiency in the Rat and Response to Treatment with 2-Methyl-3-Hydroxy 4,5-Dihydroxymethyl-Pyridine (Vitamin B 6 )

Vitamin B₆ deficiency in rats was first described by Gyorgy. 1 From the macroscopic appearance of the skin lesions he coined the term “rat acrodynia”. Many investigators have since confirmed Gyorgy's description of the symptoms. This investigation was initiated in order to study the histopathology of this deficiency and the histogenesis of the changes effected by synthetic vitamin B_6.

supplemented with 40 micrograms each of thiamin and riboflavin and 0.5 mg of nicotinic acid. No attempt was made to supply factor II in this series of experiments. The characteristic dermatitis became evident after 6 to 9 weeks. The animals were maintained on the deficient diet for 72 to 86 days. By this time the symptoms were very severe: The paws were denuded, edematous and moist, the ears thickened and scaly, the snout swollen and some ulcers present under the tongue. Many of the rats showed roughness and redness of the surface of the lower abdomen.

Histological findings: At this stage the epithelial cells of the ears were somewhat larger than normal. The stratum granulosum was wider and instead of the usual 1 to 2 layers in thickness, extended over 4 to 5 layers. Hyperkeratosis was extreme. The stratum lucidum was also thicker and on its external side faded imperceptibly into the stratum corneum. Intercellular edema was striking and acanthosis was present. In places there was necrosis, especially at the tips of the pinna. Polymorphonuclear leucocytic infiltration appeared, particularly in the necrotic regions. Frequently serum or polymorphonuclear aggregates were present in the region of the stratum granulosum, giving the appearance of serous and purulent vesicles. Edema with polymorphonuclear leucocytes was also present in the subcutaneous tissues. The hair follicles and sebaceous glands were inconspicuous.