ABSTRACT
Objective To estabhsh an ischemic model of intratemporal facial nerve (IFN) via the mastoid process approach.Methods From February,2015 to December,2015,45 SD rats were divided randomly into an operation group (n=35) and a shame group (n=10) in random,the right side facial nerve was used for the operation and the left side served as the control in both groups.Establish the IFN ischemia model by interrupting the petrosal artery through the mastoid process approach.Facial nerve function were evaluated at the 12h and everyday postoperatively for 28 days.The degree of IFN swelling were studied by taking paraffin sections of the decalcified temporal bone containing the IFN instantly and at the 1st,3rd,7th,14th and 21st days postoperatively.Then calculated the ratio of the cross-sectional area of the IFN and the facial canal (FN/FC).The data of behavior assessment and FC/FN were analyzed using ANOVA.Twenty-eight days after the insult,took continuous sections of brainstem containing facial nucleus,then counted the number of the facial neurons.At last,analysed the results of both operation and control sides in each group by using the student-t test.Results Facial nerve paralysis developed at 12 hour after surgery,then continued deteriorated till the 7th day.By the 28th day postoperatively,all rats in surgery group recovered and data showed no significance statistically when compared with the shame group (P＜0.05).From the value of FN/FC in different groups,the nerve were found swelling in the facial canal was increasing from the 1st postoperatively and reach the peak value at the 7th day after surgery.By the 21st day,the FN/FC come to steady but remain significant statistically when compared with the contralateral side(P＜0.05).In the operation group,facial neurons of injury side exhibited significantly loss [(41.5±3.8)％] when compared with the shame group [(98.1±4.0)％](P＜0.05).Conclusion Rats with petrosal artery interrupted exhibited significant deficits.This approach involved less tissue injury,studies on the mechanisms and therapy could become more reliable using this approach.