Expression And Significance Of Sonic Hedgehog In Neuropathic Pain Model Rats

Objective : To analyze the activation of sonic hedgehog(Shh) signaling pathways in the rat model of Neuropathic pain and the dynamic changing regularity over time,and explore the role of Shh in the neuropathic pain.Methods: Eighty adult male SD rats were randomly allocated into two groups(n=40): CCI group and sham-operated group. Right sciatic nerve was ligated by4.0 silk suture in CCI group, only exposed in sham-operated group.General behavior of the two Groups respectively were observed to determined mechanical withdrawal threshold in rats after modeling 1,4,7,14,28d;The expression of Shh、Gli in the spinal cord of the rat lumbosacral enlargement were analyzed using Western-blot and immunohistochemistry.Results : The difference of preoperative MWT between CCI group and Sham group rats was not statistical significant(P = 0.832), the rest of all time points were significantly lower after the operation(P < 0.01);The MWT of CCI group began to decrease on the postoperative first day(P = 0.002), then achieved a minimum on the day 7(P = 0.027), and it was still in lower level on the day 28(P = 0.003). The protein expression of Shh 、Gli in CCI group rats was not significantly change than the Sh group on the postoperative first day(P = 0.215), and Shh 、 Gli in the CCI group were significantly increased on the rest of all time point(P < 0.01);The protein expression of Shh 、 Gli in the CCI group was upregulated seventh day after injury with maximal expression levels(P<0.01),This high level of expression was maintained up to at least 28 d after injury(P<0.01). Immunohistochemistry showed that the Shh and Gli protein displayed significantly increased in the corresponding region than the Sham group on the postoperative seventh day(P < 0. 01).Conclusion: Neuropathic pain can induce the expression of Shh signaling pathways. The expression of Related proteins reached the peak level on day 7 and maintained the high level till day 28.