The Study Of The Mechanism JAK2/STAT3 Signaling Pathway On Neural Function Recovery In Rats With Spinal Cord Injury

Background Spinal cord injury(SCI)is a serious injury of the central nervous system,which leads to sensory deprivation below the level of the injured segment,motor function and incontinence and brings heavy economic burden to society and families.After spinal cord injury,JAK2/STAT3 signaling pathway can be activated instantly,which can participate in the regulation of inflammation and apoptosis of spinal cord injury.Therefore,it is great necessary to study the JAK2/STAT3 signal pathway after spinal cord injury.JAK2 phosphatase inhibitor AG490 was used to interfere with the phosphorylation of JAK2 and block the transduction of JAK2/S.TAT3 signal pathway.Observe the gene and protein changes of P-JAK2,P-STAT3,IL-6 and Bcl-2.To explore the role of JAK2/STAT3 signal pathway in spinal cord injury and provide theoretical clinical treatment.Objective:1.To investigate at different time the expression of JAK2/STAT3 signaling pathway after spinal cord injury.2.The study of the mechanism JAK2/STAT3 signaling pathway on neural function recovery in rats with spinal cord injury.Method:1.The rat spinal cord injury model was established by clamping spinal cord.2.Detection gene expression of JAK2,STAT3,Bcl-2 and IL-6 by RT-PCR.3.The protein expressions of P-JAK2,P-STAT3,Bcl-2 and IL-6 were detected.4.BBB Score was used to detect the behavior of rats.5.Paraffin sections of spare spinal cord tissue were made and Tunel staining was performed to detect the apoptosis of spinal cord neurons and immunohistochemical quantitative analysis of paraffin sections.6.The data was processed by using SPSS20.0 software(IBM Corp.);One-way analysis of variance was used for comparison between groups.AP-value of less than 0.05 was considered statistically significant.Result:1.Spinal cord injury rats crawl only by the forelimbs,which ankles,knees and hip joints can not move independently and the tail can not swing independently.2)JAK2/STAT3 signaling pathway was activated immediately after spinal cord injury.JAK2 and STAT3 genes were significantly increased compared with Sham group.3)BBB score,the Sham group 1,3,7,14 days to maintain healthy state averaged 20.75 points;SCI group 1 day score were 0 points,3 days score averaged 1.78 points,7 days score averaged 3.41 points,14 days score averaged 4.95 points.2.The protein expression of P-JAK2 and P-STAT3 was detected by Western blot immediately after pinal cord injury,Compared with SCI group,the expression of P-JAK2 and P-STAT3 in SCI+AG490 group decreased significantly on the 1st,3rd and 7th day after using JAK2 phosphatase inhibitor.The expression of IL-6 protein in SCI group was significantly higher than that in Sham group at day 1 and 3,and significantly lower than that in SCI+AG490 group compared to SCI group.The expression of Bcl-2 protein in SCI group was higher than that in Sham group from day 1,but in SCI+AG490 group,the expression of Bcl-2 protein decreased significantly.After the success of the four groups,BBB score was used to detect the behavior of rats the average score of Sham group was 20.75,Vehicle group was 20.87,SCI group was 3.33 and SCI+AG490 group was 2.14.Immunohistochemical results showed that the expression of P-JAK2,P-STAT3 and IL-6 in SCI group and SCI+AG490 group increased significantly after spinal cord injury,and the number of positive cells reached the maximum on the third day.The expression of P-JAK2 and P-STAT3 protein in SCI+AG490 group was significantly lower than that in SCI group.On the contrary,the number of BCL-2 positive cells in SCI group was significantly higher than that in SCI+AG490 group.Tunel staining of paraffin sections of spinal cord showed that the number of positive neurons in SCI+AG490 group was significantly higher than that in SCI group after blocking JAK2/STAT3 signaling pathway with AG490.Conclusion:1.The results of spinal cord injury in rats after spinal cord injury showed that P-JAK2 and P-STAT3 functional proteins increased significantly in the injured group and reached the peak on the third day,indicating that JAK2/STAT3 signaling pathway is closely related to the process of spinal cord injury.2.After activation of JAK2/STAT3 signaling pathway in spinal cord injury,the expression of JAK2 and STAT3 was positively correlated with the expression of IL-6,and positively correlated with the expression of Bcl-2 could inhibit the expression of inflammatory factor IL-6,increase the expression of Bcl-2,reduce neuronal edema and inhibit neuronal apoptosis.