Abstract: Objective To observe the expression of induced nitricoxide synthase(iNOS)in ligustrazine against cisplatin-induced ototoxicity.Methods Fifty white guinea pigs with normal hearing were randomly divided into the control group,ligustrazine group and traditional Chinese drug(TCD)group.The alternations of hearing function were evaluated by the examination of auditory brainstem response(ABR).Some specimens were perfused by AgNO₃ and observed the damage of bristle cell.And some were sent for immunohistochemistry to detect the expression of iNOS.Results Compared with the control group,the threshold of ABR in ligustrazine group and TCD group were significantly different.There was a significant difference between the ligustrazine group and TCD group.There was no expression of iNOS in Cortis',spiral ganglion cell and stria vascularis in normal cochlear(control group).In the ligustrazine group,the expression became stronger in spiral ganglion cell,stria vascularis,spiral ligament and Cortis'.INOS also expressed in TCD group.Conclusion Ligustrazine can antagonize cisplatin-induced ototoxicity by inhibiting the expression of iNOS.

Key words: cisplatin, ligustrazine, induced nitricoxide synthase(iNOS)