The Effect Of Ligustrazine On Gentamicin-Induced Expression Of Otoferlin And AP-2 In Guinea Pig Cochlear

Objective Based on the functionality of otoferlin and AP-2 played in the occurrence of ototoxicity caused by gentamicin,explore the intervention mechanism of ligustrazine and provide a supplementary method to the treatment of ototoxic deafness.Methods Screening with healthy white red-eye 80 guinea pigs,randomly divided them intofour groups:GM group(GM 80mg·kg-1·d-1 intramuscular injection),GM+TMP group(GM 80mg·kg-1·d-1 intramuscular injection and TMP 10mg·kg-1·d-1 intraperitoneal injection respectively),TMP group(TMP 10mg·kg-1·d-1 intraperitoneal injection)and normal saline group(NS).NS group was given NS as the same amount asthe GM group.Guinea pigs from each group were continuously given drugs for 12 days.To detect the hearing threshold of each group by ABR measurement.At the same time,cochleas were prepared to be formalin-fixed paraffin-embedded format,then cochlearslices and HE dye were done and the structure of Corti’s organ and outer hair cells wereobserved.Western blot method was used to examine otoferlin and AP-2 expression level.Results 1.From the results of click ABR test,the ABR threshold of GM group was increased significantly after Ototoxic GM exposure compared with NS group(P<0.05):The threshold of GM+TMP group showed significant difference with GM group(P<0.05),but still higher than NS group(P<0.05).2.From the observation of cochlear slices,the histomorphology of cochlea got from NS group and TMP group was normal;The Corti’s organ of GM group was severely deformative with OHC swelling,and there are lots of cells missing and cavitation in the spiral ganglion;The situation in the GM+TMP group was slightly changed,but better than GM group.3.From the western blot results,there was a significant difference in expression of otoferlin and AP-2 between GM group and other groups(P<0.05),indicating that the otoferlin and AP-2 expression decreased significantly;GM+TMP group has a higher expression of otoferlin and AP-2 than GM group(P<0.05).There was no significant difference between NS group and TMP group(P>0.05);4.There was a significant negative correlation between otoferlin and AP-2 protein witn ABR response threshold expression in guinea pig cochlea(P<0.05)Conclusion 1.Ototoxic GM exposure causes high ABR threshold and low expression of otoferlin and AP-2 in cochlear,which indicating that otoferlin and AP-2 might be involved in the pathological process of hearing loss caused by GM.2.TMP could effectively attenuate GM ototoxicity by protecting otoferlin and AP-2 normal-expression induced by GM,this might be one of the molecular mechanisms by which TMP could protect against GM ototoxicity.