| Objective: Postoperative pain is the pain that patients feel in different degrees after operation.At present,the current treatment situation is not optimistic,because its pathophysiological mechanism is not particularly clear.And in many studies,we have found that the multifunctional differentiation factor activin-A,which can play an important role in the inflammatory response.Therefore,this experiment intends to observe the changes of activin-A,p38 MAPK,inflammatory factors(TNF-α,IL-1β)and heat shrinkable foot latency(TWL)in the spinal cord at different time points before modeling,2h,6h and 24 h after modeling through the rat incision pain model proposed by Brennan et al.To explore whether activin-A can play a role in the inflammatory response of spinal cord to incision pain in rats by mediating p38 MAPK pathway,so as to provide a new idea for the treatment of postoperative acute pain.Methods: A total of Forty-eight 1-month-old SD rats were randomly divided into four groups(n=12): sham-operation group(S group),incision group(I group),sham-operation+ antagonist group(SA group)and incision pain + antagonist group(IA group).The rats were injected with an antagonist(Follistatin 5ug/kg)30 minutes before the model was established,and then injected with 10% Chloral hydrate 400mg/kg into the abdominal cavity to make the model of incision pain.At before modeling(T0),2 h,6 h and 24h(T1-3)after the establishment of the model,the latent period of thermolysis foot(TWL)was measured.After the determination of behavioral heat pain threshold,they were anesthetized with an intraperitoneal injection of 10% Chloral hydrate,then the L4-6 segment of spinal cord was harvested.Finally the expression levels of activin-A and p38 MAPK in spinal cord were detected by q PCR,and the expression levels of activin-A,TNF-α,IL-1β in spinal cord were detected by Elisa.Results:1.Animal behavior test results: The difference was not statistically significant in TWL before modeling in every group;TWL In group I and group IA decreased significantly at all time points,and lasted until 24 h after model establishment;In comparation with S group,there was no statistical significance in TWL at all post-operative time points in SA group,but TWL in I group and IA group decreased significantly;Compared with group I,the TWL in group IA was significantly longer at2,6 and 24 hours after operation.2.Elisa results: The difference was not statistically significant in the expression of activin-A,TNF-α and IL-1β in spinal cord of rats in each group before operation;The expression of activin-A and inflammatory factor(TNF-α,IL-1β)in the spinal cord of group I and group IA were significantly higher than that of preoperation,Moreover,the expression of TNF-α and IL-1β in the spinal cord was significantly increased at 6h in group I and IA;Compared with S group,The difference between S group and SA group were not statistically significant,however,at2 h,6h and 24 h after operation,the expression of activin-A and inflammatory factor(TNF-α,IL-1β)in the spinal cord of group I and group IA was markedly increased;Compared with group I,the expressions of activin-a,TNF-α and IL-1β in spinal cord of rats in group IA were significantly decreased.3.q PCR Results: The m RNA expression of activin-A and p38 MAPK in spinal cord of each group was not significant;The m RNA expression of activin-A and p38 MAPK in the spinal cord of group I and group IA was increased at each time point;Compared with group S,the expressions of activin-A and p38 MAPK in spinal cord of group I and group IA were significantly increased;Compared with group I,the expression of activin-A and p38 MAPK in spinal cord of group IA was significantly decreased at 2,6 and 24 h,and the difference was not statistically significant between group S and group SA.Conclusion: 1.In the rat model of incisional pain,Activin-A may induce pain by mediating p38 mitogen-activated protein kinase(p38MAPK)pathway to stimulate the spinal inflammatory response.2.Follistatin,an activator-a antagonist,relieves inflammatory response to partial incisional pain. |
PDF Full Text Request