アミノ配糖体抗生剤によるウサギおよびモルモットの内耳障害に関する比較研究

Abstract

The difference in the ototoxic vulnerability between rabbits and guinear pigs was examined with three aminoglycoside antibiotics, kanamycin (KM), dibekacin (DKB) and gentamicin (GM). Hair cell damage was determined under a phase contrast microscope with the surface preparation technique. The perilymph concentration of the drugs, DKB and KM, was measured by the bioassay method.Hair cell damage of rabbits, which were given KM 100mg/kg, DKB 100mg/kg and GM 50 mg/kg for 30 days, was almost the same as or severer than that of guinear pigs which were given a double dosage. The hair cell vulnerability of rabbits was twice that of guinea pigs, but there were no differences between the two species in the perilymph concentration of the drugs and in the renal damage. Therefore it is suggested that the cause of the different ototoxic vulnerability between the two species is due to the difference in the hair cell susceptibility to aminoglycoside antibiotics and that the hair cells of rabbits are more susceptible than those of guinea pigs.There was also the species difference in the pattern of the outer and inner hair cell damage. Outer hair cell damage of the rabbits began from the basal turn to the upper turns, as a rule. In some guinea pigs, however, it often began from not only the basal turn but also the upper turns. The transition from the region having a normal arrangement of hair cells to that showing complete hair cell loss was abrupt in rabbits. But that was gradual in guinea pigs. Inner hair cell damage of the rabbits usually began from the basal turn to the upper turns just as did the outer hair cell damage, but in some guinea pigs they began from the apical turn toward the lower turns.The pattern of hair cell damage of rabbits was more similar to those of human or monkeys in the literature and the ototoxic vulnerability of rabbits was also more similar to that of monkeys. Therefore it is thought that rabbits are more useful experimental animals to expect the safety to aminoglycoside antibiotics in human.