Changes in morphofunctional condition of the cochlear vascular stripe in response to the ototoxic antibiotic

The experiments were made on guinea pigs injected i.m. kanamycin for 7 and 14 days in a dose 400 mg/kg. The cochleas of the guinea pigs were studied electron microscopically after 7- and 14-day courses of the antibiotic and 30 days after the end of aminoglycoside administration. To assess the vascular stripe (VS) function, the number of secretory vacuoles in apical cytoplasm of the marginal cells on the ultrathin sections was calculated. The animals which had got kanamycin for 7 days exhibited insignificant VS ultrastructural alterations, the number of vacuoles in the marginal cells (38.9 +/- 2.4) was higher than normal (33.9 +/- 1.5) but the difference was insignificant. After 14-day administration of the antibiotic VS of the animals had noticeable ultrastructural disorders of the interstitial and marginal cells and statistically significant (p < 0.01) suppression of secretory activity of the marginal cells (18.6 +/- 1.1). Natural reparative processes normalized ultrastructure of all types of VS cells 30 days after kanamycin discontinuation though secretion in the marginal cells remained significantly subnormal (the number of the vacuoles reduced to 23.4 +/- 1.7). Thus, aminoglycoside antibiotic kanamycin induces morphofunctional disorders in VS cells which do not return to normal after 30 days of follow-up.