기니픽의 전정기관 감각유모세포에 대한 Aminoglycoside의 영향

Abstract

Experimental studies about the effects of various ototoxic drugs were performed by many authors, and among them antibiotic aminoglycoside-related ototoxicity has been widely studied. The histopathology of aminoglycoside ototoxicity has been relatively well described, but still many aspects are remained to be revealed and especially domestic studies are very insufficient. The authors applied small amount of gentamicin(GM) and streptomycin(SM) to the guinea pig through the fenestration of lateral semicircular canal, and sacrificed the animals at 4th and 8th weeks postoperatively.

The authors performed in vivo fixation with 1% osmium tetroxide and post-fixation with modified Karnovsky's fixative. The three semicircular canals were obtained by microdissection. The cristae ampullares were embedded in the Immunobed kit and cut with the thickness of 2㎛ by Reichert-Jung Supercut. The mid-portions of each crista ampullaris were collected and stained with Hematoxylin and Eosin. The mounted slides were analyzed under light microscope with the image analyzer system.

The results are as follow ; The distribution of sensory hair cells, especially type I cells showed a tendency to decrease in general, and was statistically significantly reduced in GM 8-week group. The areas of the epithelial layer and sensory cells also showed a tendency to decrease, but not so much extent as the decrease of cell numbers. The distribution and area of supporting cells didn't show a big difference between each group, but showed a statistically significant reduction in GM 8-week group.

In conclusion, the crista ampullaris resulted in the loss of sensory hair and degenerative cell changes after aminoglycoside application. The numbers of hair cell had a decreasing tendency generally. The result of supporting cell reduction in one group should be further discussed. These results are thought to be a useful data for the study of vestibular pathophysiology induced by ototoxic drugs.

Experimental studies about the effects of various ototoxic drugs were performed by many authors, and among them antibiotic aminoglycoside-related ototoxicity has been widely studied. The histopathology of aminoglycoside ototoxicity has been relatively well described, but still many aspects are remained to be revealed and especially domestic studies are very insufficient. The authors applied small amount of gentamicin(GM) and streptomycin(SM) to the guinea pig through the fenestration of lateral semicircular canal, and sacrificed the animals at 4th and 8th weeks postoperatively.

The authors performed in vivo fixation with 1% osmium tetroxide and post-fixation with modified Karnovsky's fixative. The three semicircular canals were obtained by microdissection. The cristae ampullares were embedded in the Immunobed kit and cut with the thickness of 2㎛ by Reichert-Jung Supercut. The mid-portions of each crista ampullaris were collected and stained with Hematoxylin and Eosin. The mounted slides were analyzed under light microscope with the image analyzer system.

The results are as follow ; The distribution of sensory hair cells, especially type I cells showed a tendency to decrease in general, and was statistically significantly reduced in GM 8-week group. The areas of the epithelial layer and sensory cells also showed a tendency to decrease, but not so much extent as the decrease of cell numbers. The distribution and area of supporting cells didn't show a big difference between each group, but showed a statistically significant reduction in GM 8-week group.

In conclusion, the crista ampullaris resulted in the loss of sensory hair and degenerative cell changes after aminoglycoside application. The numbers of hair cell had a decreasing tendency generally. The result of supporting cell reduction in one group should be further discussed. These results are thought to be a useful data for the study of vestibular pathophysiology induced by ototoxic drugs.