SCANNING ELECTRON-MICROSCOPIC OBSERVATION OF DARK CELLS AFTER STREPTOMYCIN PERFUSION OF THE VESTIBULE IN GUINEA-PIGS

Hearing has been stabilized in the majority of patients studied in the treatment of Meniere's disease with streptomycin. This observation su ggests that effects of streptomycin may ameliorate endolymphatic hydro ps, possibly by attenuating the activity of secretory tissue. The purp ose of this study is to observe the dark cells of the utricle in guine a pigs after streptomycin perfusion of the vestibule. Twelve pigmented guinea pigs weighing 250-350 grams were used in this study. The vesti bules in five guinea pigs were perfused monolaterally with 150 mu g of streptomycin in artificial perilymph and, in seven, the vestibules we re perfused only with artificial perilymph as a control group. Specime ns were processed for observation with a scanning electron microscope. After streptomycin perfusion, the margin of the dark cells became ind istinct. The luminal surface of the cells bulged out like a dome. The microvilli decreased or were absent, and some debris was deposited on the surface. In four of the five animals, the luminal membrane of the dark cell ruptured. The cytoplasm and organelle extruded into the endo lymphatic space. After the cellular debris moved out into the endolymp h, either a vanished cell or a nucleus in an empty nest was observed. These cells appeared damaged and destroyed. The results indicate that the dark cells in the membranous wall of the utricle were affected by streptomycin. The results lead to the assumption that streptomycin may reduce the volume of endolymph by damaging the dark cells of the utri cle.