Abstract:

Objective     To establish an animal model of facial nerve palsy in mice induced by   herpes simplex virus type 1 (HSV-1) infection so as to investigate expression of glucocorticoid  receptor (GR) in the motor cortex and facial nucleus. Methods     A total of 89 four-week-old female Balb/c mice were selected. These animals were randomly divided into two groups, i.e., the control group without any intervention, and the experimental group in which 25μL HSV1 was inoculated into the right auricle after scratching the surface of bilateral auricles with a 26 gauge needle. The tissues were taken out at 6h, 12h, 24h, 48h, 72h, and 7d after the appearance of facial nerve palsy. Western blot and immunohistochemistry were used to detect the level of GR protein, RT-PCR was used to measure the level of GR mRNA.  Results      The incidence of facial nerve palsy was 52.3% among the 81 inoculated animals. GR was localized in the facial nucleus. GR mRNA expression in the experimental group was slightly decreased after facial nerve palsy in the motor cortex and facial nucleus, and sharply declined at 6 h, showing a significant difference compared with the controlgroup (P<0.05).  Expression gradually reached a peak at 48h, having a significant difference compared with the control group (P<0.01). Expression eventually returned to the baseline level on and beyond the 7th day, however, no difference between the two groups was identified(P>0.05). GR protein expression in the experimental group was similar to GR mRNA.  Conclusions     GR expression in response to HSV1 infection appears in a timedependent manner, indicating that GR expression level is closely related to the progress of HSV1-induced facial nerve palsy. These findings may be of important clinical implication in the rational of use of glucocorticoid and attenuation of hormone resistance in the treatment of Bell′s facial paralysis.

Key words: Receptor；Glucocorticoid； Herpes simplex virus type 1； Facial paralysis