An Effect of Allopurinol on Salicylate Ototoxicity in Guinea Pigs / 대한이비인후과학회지

The mechanism of salicylate ototoxicity appears to be multifactorial and decreased cochlear blood flow seems to play an important role. The purpose of the study was to assess an effect of allpurinol, a blocker of free oxygen radicals(FORs) formation, on salicylate ototxicity in guinea pig. ABR threshold shifts were observed in group 1, treated with salicylate(300mg/kg, IM) and group 2, pretreated with allopurinol(50mg/kg, PO, two times) before injection of salicylate(300mg/kg, IM). In group 1, significant ABR threshold shift was measured in 1 hour(p<0.05) and maximum threshold shift was noted in 2-3 hours, with complete recovery in 6 hours, after injection of salicylate. In group 2, there was a little ABR threshold shift through 6 hours after injection of salicylate, except average 5dB shift in 4 hours. ABR threshold shift was significantly greater in group 1 than in group 2, after injection of salicylate(p<0.05). With above result, allopurinol, a blocker of FORs formation, could attenuated the hearing loss after the administration of salicylate in guinea pig, and FORs might play a role in salicylateinduced hearing loss.

An Effect of Ginkgo Extract on Salicylate Ototoxicity in Guinea Pigs / 대한이비인후과학회지

BACKGROUND: The mechanism of salicylate ototoxicity is probably related to reversible biochemical or metabolic changes in the cochlea. Decreased cochlear blood flow seems to play an important role in salicylate ototoxicity. Several constituents of ginkgo extract have the action of increasing blood flow, antagonism of platelet activating factor and scavenger of free radicals. It might be thought that these activities of ginkgo extract could contribute to attenuate salicylate ototoxicity. OBJECTIVES: Whether the salicylate induced hearing loss could be attenuated by pretreatment with ginkgo extract. MATERIALS AND METHODS: Auditory brainstem response threshold changes were observed after the intramuscular injection of lysine salicylate(300mg/kg), or lysine salicylate with EGb 761(100mg/kg, single IP or 100mg/kg and 50mg/kg, IP, two times) pretreatment in each group of guinea pig. RESULTS: In the groups with Ginkgo extract pretreatment, the threshold changes were less severe and recovered earlier than in group with salicylate injection only(p<0.05). CONCLUSIONS: EGb 761 could attenuated the hearing loss after the injection of salicylate in guinea pig.