Effects Of Vagal Nerve Activity Regulation On Intestinal Barrier Function In Sepsis Rats

Objective:To observe the effects of vagus nerve activity regulation on intestinal barrier function,blood inflammatory factors in septic rats,and to explore the possible anti-inflammatory mechanisms.Methods:Sixty male rats（224.6±8.5g）were randomly divided into six groups（n=10）:shame control（group control）,sepsis（group sepsis）,sepsis+dexmedetomidine（group S+D）sepsis+methyllycaconitine（group S+M）,sepsis+vagal nerve stimulation（S+E）,sepsis+vagus nerve block（group S+B）.Sepsis rats modle was made by Cecal ligation and puncture（CLP）.Post operation rats in group S+D were treated with dexmedetomidine 5ug·kg^-1·h^-1 by continuous pump injection;group S+M were treated with methyllycaconitine 5mg·kg^-1 Intrper-itoneal injection;group S+E were treated withl eft cervical vagus nerve stimulation;group S+B were treated with left cervical vagus nerve block.All rats were treat with saline 5ml·kg^-1·h^-11 except the rats in group S+D.All rats were killed after CLP modle establishment.Rats’serum and small intestine tissue were collected.The pathological changes of rats’small intestine tissue were observed with microscope;serum levels of D-lactate,TNF-αand IL-6 in each group were detected by enzyme linked immunosorbent assay（ELISA）;the expressions of Occludin andα7 nicotinic acetylcholine receptor（α7nAChR）in small intestine were detected by Western blot（WB）.Results:（1）Compared with group control,rats’serum D-Lac、TNF-α、IL-6 level in group sepsis were significantly increased（P<0.05）and the expression of Occludin in the small intestine of group sepsis was decreased（P<0.05）;compared with group sepsis,rats’serum D-Lac、TNF-α、IL-6 level were significantly decreased in group S+D and group S+E（P<0.05）and the expression of Occludin in the small intestine of group S+D and S+E were up-regulated（P<0.05）;compared with group sepsis,rats’serum D-Lac、TNF-α、IL-6 level were significantly increased in group S+M and S+B（P<0.05）and the expression of Occludin in the small intestine of group S+M and S+B were decreased（P<0.05）.There was no significant difference in rats’serum D-Lac、TNF-α、IL-6 level between group S+D and group S+E（P>0.05）;there was no significant difference in rats’serum D-Lac、TNF-α、IL-6 level between group S+M and group S+B（P>0.05）.（2）Compared with group control,there is a significant intestinal pathological damage in group sepsis、group S+D、group S+E、group S+M、group S+E and group S+B.The intestinal tissue injury in group S+D and S+E were lighter than group sepsis;the intestinal tissue injury in group S+M and S+B were heavier than group sepsis.（3）Compared with the group control,the expression ofα7nAChR in the small intestine of group sepsis was decreased（P<0.05）;compared with the group control,the expression ofα7nAChR in the small intestine of groupS+D and S+E were up-regulated（P<0.05）;compared with the group sepsis,the expression ofα7nAChR in the small intestine of group S+M and S+B were decreased（P<0.05）.The expression ofα7nAChR in group S+D and group S+E had no significant difference（P>0.05）;the expression ofα7nAChR in group S+M and group S+B had no significant difference（P>0.05）.Conclusion:Increased vagal activity can protect intestinal barrier function in septic rats.Dexmedetomidine can activateα7nAChR to protect intestinal barrier function of sepsis rats by increasing vagal activity.