Experimental Study Of Expression Change Of Heat Shock Protein27in Facial Motor Nucleus After Facial Nerve Axotomy

Although facial paralysis is a relatively common disease, still certain aspects of its pathogenesis have not been fully explained. With its first line therapies far from perfect, it has become one of the scientific frontiers nowadays, to further clarify of the mechanisms of the functional recovery of the facial nerve post-injury. In2003, Japanese scholar discovered that, after injury of facial nerve, the survival of facial motor neurons is significant for the functional recovery of facial nerve. This conclusion led the study on facial paralysis to focus not only on the peripheral facial nerve, but also on the status of survival of facial motor neurons in the facial motor nucleus after injury to the peripheral facial nerve. Studies showed that Heat Shock Protein27could be relevant to the survival of facial motor neurons after facial nerve axotomy.Objective:to study the change of the level of heat shock protein27in facial motor nucleus after facial nerve axotomy, further explore the molecular mechanism of recovery of the function of facial nerve after facial paralysis;Method:30Wistar rats are randomized into3groups:experimental group, surgical control group, and blank control group, so there were10rats in each group. The experimental protocol was as follows:1, sample collection:at the5time points of pre-and1,2,3,4days post-right facial nerve axotomy, collect the sample of right facial motor nucleus of2rats in the experimental group; at the same time points, collect the sample of right facial motor nucleus from2rats in the surgical control group, whose surgical procedures had been the same except for facial nerve axotomy; at the same time points, collect the sample of right facial motor nucleus from2rats in the blank control group, that had been through no surgical procedure; collect liver sample randomly from1rat in each group, as positive control;2, protein extraction:collect supernatant containing heat shock protein27from the collected tissue samples;3, western-blot measurement: determine the level of heat shock protein27at the various time points in the three different experimental groups by use of westernblot;Results:in the experimental group, the expression level of heat shock protein27in facial motor nucleus was significantly up-regulated on the1st day post-facial nerve axotomy than pre-facial nerve axotomy, peaked on the2nd day post-facial nerve axotomy, declined on the3rd day post-f1cial nerve axotomy, and further declined on the 4m day post-FNA, which was still higher than the expression level pre-facial nerve axotomy; in the surgical and blank control group, there was no significant difference in the level of heat shock protein27.Conclusions:1, compared with control groups, the level of heat shock protein27was obviously up-regulated in facial motor nucleus on the1st day post-facial nerve axotomy, peaked on the2nd day post-facial nerve axotomy, and then gradually declined, but still remained higher than the level pre-facial nerve axotomy.2, heat shock protein27was an effecter (maybe one of the effecters) of the stress reaction of facial motor neurons in the facial motor nucleus in response to the injury of facial nerve axotomy.3, But the exact time of up-regulation of heat shock protein27and the exact time of its peaking in facial motor nucleus after facial nerve axotomy were unclear, nor was duration of the elevated level of heat shock protein27, all of which needed further exploration.