Round Window Membrane in Serous and Purulent Otitis Media: Structural Study in the Rat

Abstract

The rat was used as an animal model to reveal structural alterations in the round window membrane (RWM) during serous otitis media (SOM) and purulent otitis media (POM) over a 6-week period. Comparison of POM animals and control animals showed that the RWM in the former became almost six times as thick as that in controls, whereas that of SOM animals was twice as thick. The structural changes in the RWM in POM animals were confined mainly to the epithelium facing the middle ear cavity and the subepithelial space, which was invaded by inflammatory cells and exhibited dilated vessels. The normal flat epithelium was transformed via cuboidal cells to a cylindric epithelium containing both ciliated and goblet cells. In SOM animals, light microscopy revealed only minor changes in the RWM structure. Ultrastructurally, however, the connective tissue layer exhibited dense aggregations of collagen, increased numbers of fibroblasts, and, in one case, elastic fibers. This last phenomenon was not observed in either POM ears or normal ears. The study showed that various inflammatory conditions of the middle ear, both noninfectious (SOM) and infectious (POM), can cause different structural alterations of the RWM. These structural changes may influence passage through the RWM differently.

Keywords

light microscopy purulent otitis media round window membrane serous otitis media ultrastructure

Get full access to this article

View all access options for this article.

References

Paparella

Bluestone

Arnold

. Panel reports. 1A. Definition and classification. In: Lim

, ed. Recent advances in otitis media with effusion. Report of research conference. Ann Otol Rhinol Laryngol 1985; 94(suppl 116): 8–9.

Munker

. Inner ear hearing loss in acute and chronic otitis media. Adv Otorhinolaryngol 1981; 27: 138–43.

Aviel

Ostfeld

. Acquired irreversible sensorineural hearing loss associated with otitis media with effusion. Am J Otolaryngol 1982; 3: 217–22.

Paparella

Brady

Hoel

. Sensori-neural hearing loss in chronic otitis media and mastoiditis. Trans Am Acad Ophthalmol Otolaryngol 1970; 74: 108–15.

Paparella

Morizono

. Sensorineural hearing loss in otitis media. Ann Otol Rhinol Laryngol 1984; 93: 623–9.

Rahko

Karma

Sipilä

. Sensorineural hearing loss and acute otitis media in children. Acta Otolaryngol (Stockh) 1989; 108: 107–12.

Hellström

Salén

Stenfors

L-E

. The site of initial production and transport of effusion material in otitis media serosa. A study on rat middle ear cavity. Acta Otolaryngol (Stockh) 1982; 93: 435–40.

Hellström

Salén

Stenfors

L-E

Söderberg

. Appearance of effusion material in the attic space correlated to an impaired eustachian tube function. Int J Pediatr Otorhinolaryngol 1983; 6: 127–34.

Hermansson

Emgård

Prellner

Hellström

. A rat model for pneumococcal otitis media. Am J Otolaryngol 1988; 9: 97–101.

10.

Widemar

Hellström

Stenfors

L-E

. Different structural changes in membrana Shrapnelli in serous and purulent otitis media. An experimental study in the rat. Acta Otolaryngol (Stockh) 1986; 102: 266–73.

11.

Hellström

Johansson

Anniko

. Structure of the round window membrane. Acta Otolaryngol [Suppl] (Stockh) 1988(suppl 457): 33–42.

12.

Johansson

Hellström

. Bacteriological characterization of the effusion material in an animal model for serous and purulent otitis media. Acta Otolaryngol (Stockh) 1990; 110: 100–4.

13.

Hellström

Nilsson

. The microwave in temporal bone research. Acta Otolaryngol [Suppl] (Stockh) 1992(suppl 493): 15–8.

14.

Albiin

Hellström

Salén

Stenfors

L-E

. Arteria stapedialis in the rat. A microscopical study under normal conditions and in otitis media with effusion (OME). Acta Anat (Basel) 1983; 115: 134–40.

15.

Nomura

. Otological significance of the round window membrane. In: Pfaltz

, ed. Advances in oto-rhino-laryngology. Vol 33. Basel, Switzerland: Karger, 1984: 1–162.

16.

Anniko

Hellström

, eds. Interaction between the middle ear and the inner ear. Acta Otolaryngol [Suppl] (Stockh) 1988(suppl 457).

17.

Richardson

Ishiyama

Keels

. Submicroscopic studies of the round window membrane. Acta Otolaryngol (Stockh) 1971; 71: 9–21.

18.

Schachern

Paparella

Duvall

III Choo

. The human round window membrane. An electron microscopic study. Arch Otolaryngol 1984; 110: 15–21.

19.

Sahni

Paparella

Schachern

Goycoolea

. Thickness of the human round window membrane in different forms of otitis media. Arch Otolaryngol Head Neck Surg 1987; 113: 630–4.

20.

Goycoolea

Carpenter

A-M

Muchow

. Ultrastructural studies of the round-window membrane of the cat. Arch Otolaryngol Head Neck Surg 1987; 113: 617–24.

21.

Carpenter

A-M

Muchow

Goycoolea

. Ultrastructural studies of the human round window membrane. Arch Otolaryngol Head Neck Surg 1989; 115: 585–90.

22.

Suzuki

Kawauchi

Fujiyoshi

Mogi

. Round window membrane and perilymph in experimental otitis media with effusion. Ann Otol Rhinol Laryngol 1989; 98: 980–7.

23.

Goldberg

Goycoolea

Schleivert

. Passage of albumin from the middle ear to the inner ear in otitis media in the chinchilla. Am J Otolaryngol 1981; 2: 210–4.

24.

Harada

Iwamori

Nagai

Nomura

. Ototoxicity of neomycin and its penetration through the round window membrane into the perilymph. Ann Otol Rhinol Laryngol 1986; 95: 404–8.

25.

Goycoolea

Muchow

Schachern

. Experimental studies on round window structure: Function and permeability. Laryngoscope 1988; 98(suppl 44).

26.

Goycoolea

Muchow

Martinez

. Permeability of the human round-window membrane to cationic ferritin. Arch Otolaryngol Head Neck Surg 1988; 114: 1247–51.

27.

Schachern

Paparella

Goycoolea

Goldberg

Schlievert

. The round window membrane following application of staphylococcal exotoxin: An electron microscopic study. Laryngoscope 1981; 91: 2007–16.

28.

Juhn

Hamaguchi

Goycoolea

. Review of round window membrane permeability. Acta Otolaryngol [Suppl] (Stockh) 1988(suppl 457): 43–8.

29.

Ikeda

Sakagami

Morizono

Juhn

. Permeability of the round window membrane to middle-sized molecules in purulent otitis media. Arch Otolaryngol Head Neck Surg 1990; 116: 57–60.

30.

Spandow

Anniko

Hellström

. Inner ear disturbances following inoculation of endotoxin into the middle ear. Acta Otolaryngol (Stockh) 1989; 107: 90–6.

31.

Johansson

Hellström

Stenfors

L-E

Stigbrand

. Sequential analysis of serum proteins in middle ear effusions. A study in rats with experimentally induced serous and purulent otitis media. Eur Arch Otorhinolaryngol 1990; 248: 63–7.