Dexamethasone And Sibelium Protective Effects On Gentamicin Ototoxicity

Objective To study the protective effect of dexamethasone and flunarizine on gentamicin ototoxicity.Methods Forty guinea pigs were randomly divided into fifve groups, For each group, on Day 1, pre-treatment auditory brainstem evoked response (ABR) peak latency and interpeak latency were obtained prior to injection of gentamicin. Gentamicin group was daily injected with 150mg/kg of gentamicin by intramuscular, and injected with 0.5ml of normal saline in abdominal subcutaneous. Protection group included three groups:DF group was daily injected with 150mg/kg of gentamicin by intramuscular, and injected with 3mg/kg of dexamethasone in abdominal subcutaneous, administered with 3mg/kg of flunarizine.D group was daily injected with 150mg/kg of gentamicin by intramuscular, and injected with 3mg/kg of dexamethasone in abdominal subcutaneous. F group was daily injected with 150mg/kg of gentamicin by intramuscular and administered with 3mg/kg of flunarizine. Control group were daily injected with 3ml/kg of normal saline by intramuscular and injected 0.5ml in abdominal subcutaneous. Each group were treated forteen days. Post-treatment ABR peak latency and interpeak latency were then recorded on Day fifteen, every guinea pigs in each group were test. Pre-and post-treatment peak latency and interpeak latency were compared to measure these changes. Histology changes of hair cell were observed after ABR test, it's include morphology of hair cell by hematoxylin stained and the number of apoptotic hair cells by TUNEL stained.Resultsâ‘ There was significant difference between Pre-and post-treatment peak latency and interpeak latency on Gentamicin group and Protection group. The post-treatment peak latency and interpeak latency on Protection group(except D group) were shorter than Gentamicin group,and DF group shorter than F group (P<0.05).â‘¡Hematoxylin stained: For Gentamicin group and D group,a large number of outer hair cell missing and arranged disorderedly; For DFgroup and Fgroup,outer hair cells arranged irregularly and few cells loss; For Control group,there were no outer hair cell loss and these cells arranged regularly.â‘¢TUNEL stained:The number of apoptosis hair cells of Model group and Protection group more than that of Control group(P<0.05).There was significant difference between the number of Model group and that of Protection group(P<0.05).Conclusions Gentamicin can induce apoptosis of cochlear hair cells; Flunarizine and dexamethasone combined flunarizine can reduce gentamicin-induced cochlear hair cells, and protect hearing, but the protective effect of dexamethasone combined flunarizine were better than flunarizine alone. small doses of dexamethasone if it used singlely have no protective effect for gentamicin-induced ototoxicity.