Expression of HSP70 in guinea pig cochlea damaged by cisplatin and protected by fosfomycin sodium
Objects Tc investigate the effect of fosfomycin sodium against cisplatin-induced ototoxicity and expression of HSP70 in guinea pig cochleae in vivo.Methods Twenty-eight guinea pigs were divided into four groups in random.Six guinea pigs were used as normal group and six treated with fosfomycin sodium by 500mg/kg intramuscular once a day.Positive group was made by utilizing cisplatin(15mg/kg body weight injected intraperitoneally,once only)contained eight animals,Together with this treatment,eight animals were treated with fosfomycin sodium thirty minutes before injection of cispiatin as protective groups. Animals in each group underwent auditory brainstem response(ABR) thresholds testing before and after treatment. We also observed the hair cell damage by stretched preparation and the expression of HSP70 by section of the cochlea. The positive sites were analyzed by the grey degree value. Results The cisplatin-treated guinea pigs were found to have elevated ABR thresholds(37.1±19.9dBsp1 P0.001) while the animals treated with fosfomycin sodium plus cispiatin all had no significant ABR thresholds shifts(8.1 ±9.6 dBspl P0.05) than normal. HSP7Q expressed weakly in Cortis',spiral ganglion cell and stria vascularis in normal cochlear. In cisplatin-treatent group,the expression become strong in spiral ganglion cell,stria vascularis spiral limbus, spiral ligament and organ of Cortis',while fosfomycin sodium can reduce the expression of HSP70 protein induced by cispiatin. The grey degree value of positive expression of HSP70 showed there were significant differences between normal ,cispiatin and fosfomycin sodium treated groups when compared each orher.Conclusions Fosfomycin sodium can reduced the elevation of ABR thresholds and protected against the damage of cispiatin-induced ototoxity to some extend. Expression of HSP70 can reflect the degree of damage cell in Cortis' organ and spiral ganglion cells in cochlea of guinea pigs when exposed to cispiatin.