[Expression of heat shock protein 70 mRNA in guinea pig cochlea with ototoxicity of gentamicin].

To examine the significance of heat shock protein 70 mRNA in ototoxicity resulted from gentamicin (GM), twenty healthy albino guinea pigs (200-250 g) of either sex with a positive Prier reflex were divided into two groups randomly. In GM group the animals received 100 mg/kg GM daily by intraperitoneal injection for 10 d. In saline control group the animals received 2.5 ml/kg saline daily by intraperitoneal injection for 10 d. Auditory brainstem response (ABR) thresholds were recorded in each animal before and 1 d after GM or saline administration. After the second ABR measurement, the expression of HSP70 mRNA in guinea pig cochlea was observed with in situ hybridization and image quantitative analysis system. The results showed that the threshold of ABR in the GM group was significantly higher than that of the saline control (P< 0.001). The expression of HSP70 mRNA was more intensive in stria vascularis, spiral ligament and spiral ganglion cells in the GM group than that of the saline control group. These results suggest that administration of gentamicin can induce the expression of HSP 70 mRNA in guinea pig cochlea, and that this effect may protect hearing function from ototoxicity.