Effects Of Intrathecal Injection Of Carbenoxolone On Spinal Astrocyte PX1 In Rats With Acute Incision Pain

Objective: To investigate the analgesic effect of intrathecal injection of carbenoxolone(CBX)on rat model of toe incision pain and the effect on gap junction protein pannexin 1(PX1),and to explore the mechanism of carbenoxolone in alleviating acute pain.Methods:102 male SD rats were randomly divided into control group(C group,n = 6),model group(IP group,n = 24),normal saline group(NS group,n = 24,NS,10 ?L),and carbenoxolone group(CBX group,n = 24,CBX,0.6 ug/10?L),inhibitor group(10panx group,n = 24,10 panx,1.25 ug/10?L).In addition to the control group,other models of incision pain were established and the corresponding drugs were injected intrathecally 30 mins pre-operation.The mechanical withdrawal threshold(MWT)and thermal withdrawal latency(TWL)were measured 30 min pre-operation and 2 h,4 h,6 h,and 24 h post-operation to determine the changes in pain behavior.Then the lumbar segment of the spinal cord was removed and stored,and the changes in the amount of PX1 in the rat spinal cord were measured by Western Blot,the co-expression of PX1 and glial fibrillary acidic protein(GFAP)were been recorded by immunofluorescence.Enzyme-linked immunosorbent assay(ELISA)was used to detect the concentrations of IL-1? and TNF-a in spinal cord of rats.Results: Compared with group C,the thresholds of mechanical pain and thermal pain in IP group and NS group decreased,the expression of PX1 protein in spinal cord increased significantly,the co-expression of PX1 and astrocytes in spinal cord increased 2 hours after operation,and the concentrations of IL-1? and TNF-a in spinal cord increased significantly at various time points.Compared with IP group,the pain threshold of CBX group was significantly increased at 2h and 4h after operation,andthe expression level of 2h,4h and 24 h PX1 after operation was significantly decreased,the co-expression of 2h PX1 and astrocytes after operation was less,and the concentrations of IL-1? and TNF-a were significantly decreased at 2h and 4h after operation.Compared with IP group,pain threshold of 10 panx group increased significantly at 2h and 4h after operation,expression of 2h,6h and 24 h PX1 decreased significantly after operation,co-expression of 2h PX1 and astrocytes was less after operation,and concentration of IL-1? and TNF-a decreased significantly at each time point after operation.Compared with CBX group,there was no significant difference in postoperative mechanical pain threshold between 10 panx group and CBX group.The thermal pain threshold increased significantly at 2h and 24 h after operation,PX1 expression decreased significantly at 2h and 6h after operation,PX1 expression increased significantly at 4h after operation,and IL-1? concentration increased significantly at 24 h after operation.Conclusion:The PX1 of rat spinal astrocytes plays an important role in the early stage of acute pain and and the maintenance of acute pain,and preoperative intrathecal injection of carbenoxolone can alleviate the hyperalgesia by inhibiting the expression of PX1 and the activation of astrocytes.