Detection And Change Of CaV1.3 Calcium Channel And Three Apoptotic Factors In Acute Drug-induced Lesion Of Inner Ear

Objective To investigate the expression of CaV 1.3 calcium channel protein and three apoptotic factors (cyt-c, caspase-3, p53) in inner ear which is damaged by co-administration of kanamycin and furosemide. To analyze the relationship between apoptosis and ototoxicity.Methods C57BL/6J mice of 4 weeks old were selected as experimental subjects which were randomly divided into experimental and control groups. Experimental mice were deafened by co-administration of kanamycin and furosemide and control mice were given normal saline injection. The auditory brainstem response(ABR) was measured before the administration of the drugs and a week after. Reverse transcription polymerase chain reaction (RT-PCR) was used to detect the level of CaV1.3 mRNA in cochlea of C57BL/6J mice in the two different groups. The expression of CaV1.3, Cytochrome C, caspase-3 and p53 were assessed and verified by immunohistochemistrical examination. The difference of expression was compared in the two groups.Results The mean value for ABR thresholds in response of the experimental group was significantly increased compared with the control group.The difference between the two groups was statistically significant (P <0.001). CaV1.3 mRNA expression was decreased in the experimental group compared with the control group. CaV1.3 calcium channel protein was found mainly in the stria vascularis, spiral ligament, spiral convex, hair cells, etc., whose expression was significantly decreased after the treatment. Cytochrome C, caspase-3, p53 was found mainly in the stria vascularis, spiral ligament, spiral convex, and hair cells; and its expression was significantly increased in the experimental mice than in the control group.Conclusion Application of kanamycin combined furosemide can cause acute cochlear lesion and hearing decline in mice. This drug-induced ototoxicity was significantly correlated with the damage of CaV1.3 calcium channel protein and the apoptosis of hair cells, stria vascularis, and spiral ganglion neuron in the inner ear.