Ototoxic Effects of a Pseudodisaccharide Aminoglycoside Antibiotic, Dactimicin, on the Inner Ears of Guinea Pigs

Abstract

The effect of dactimicin on the inner ear of guinea pigs was investigated by comparing it with the effects of ribostamycin, astromicin and amikacin. At doses of 200 and 400 mg/kg/day for 4 weeks, no pinna reflex loss was observed, but 2 animals receiving 400 mg dactimicin/kg/day showed unilateral loss of the outer hair cells in the cochlea and very scattered loss of the hair cells in the vestibular organ. At doses of 400 and 500 mg dactimicin/kg/day for 5 weeks, all surviving animals showed no abnormality of the outer hair cells, the inner hair cells and the spiral ganglion cells in the cochlea except for scattered unilateral loss of the outer hair cells and loss of the stria vascularis. Based on these observations, it is concluded that the ototoxicity of dactimicin on the inner ear of guinea pigs is the same as or a little stronger than that of ribostamycin, weaker than or the same as that of astromicin and weaker than amikacin.

Ototoxic Effects of 2', 3'-Dideoxy-1-N-Isoseryl Kanamycin A (ISDK) on the Inner Ear in Guinea Pigs

“…Previous studies of the ototoxicity of aminoglycoside antibiotics have demonstrated that the outer hair cells regularly disappear from the basal end to the upper turns of the cochlea. At the same time, the pinna reflex response regularly shows a loss from a high frequency (20 KHz) to a low frequency12, 15,16).…”

Comparative Ototoxicity of Ribostamycin, Dactimicin, Dibekacin, Kanamycin, Amikacin, Tobramycin, Gentamicin, Sisomicin and Netilmicin in the Inner Ear of Guinea Pigs

“…In the case of cochlea damages, disap pearance of the outer hair cells extends from the basal end to the upper turns. At the same time, the pinna reflex responds to a loss of the auditory functions [1,2,8,9,25], The threshold of the pinna reflex re sponse decreases from 20 kHz to lower frequencies in guinea pigs receiving ami- noglycoside antibiotics. The threshold shift is closely related to morphological changes in the hair cells of the cochlea in histological findings [1,2,8,25].…”

“…However, nephrotoxicity and ototoxicity as main adverse reactions were found for these an tibiotics [3,8,24]. Ototoxicity has been in vestigated in patients as well as experi mental animals such as rats, rabbits, guin ea pigs, dogs and monkeys [2,4,6,7,9,14,25,26]. Ototoxicity caused by amino glycoside antibiotics involves two types of impairment: (1) impairment of the vestibu lar functions characterized by loss of body equilibrium function, and (2) impairment of hearing characterized by morphologi cal changes in the cochlear hair cells [2,4,5,7,11,16,21].…”