Effects Of Sinomenine On Expression Of GLT-1 And GLAST MRNA In Spinal Cord Of Neuropathic Pain In Rats

Objective:The aims of this article are to investigate the effects of Sinomenine (SIN) on the expressions of GLT-1 and GLAST mRNA in spinal cord of chronic constrictive injury modle in rats of sciatic nerve,and to value the curative effects and propose the potential mechanism of Sinomenine to neuropathic pain,so that we may provide a new way for the treatment of neuropathic pain.Methods:Seventy two male Wistar rats whose weight ranges from 180g to 220g,whose age ranges from 6 to 8 weeks,were randomly distributed into 3 groups (24 each):sham operation group (group S),Neuropathic Pain(NP) group; group SIN.The animals received anesthesia with intraperitoneal 10% chloral hydrate 350 mg/kg. In groups NP and SIN,in accordance with the method described by Bennett et al,4 ligatures were placed on the right sciatic nerve at 1 mm intervals with 4-0 silk thread.In group S,we only expose the right sciatic nerves,but not ligate them.In group SIN, rats was injected intraperitoneally once daily with Sin 40 mg/kg until the day when the animals were sacrificed,the first time of the injection was performed immediately after the chronic constrictive injury(CCI)operation.Meanwhile,the rats received equal volume of normal saline by the same means in groups S and NP.Six animals in each group were chosen to measure mechanical paw withdrawal threshold to von Frey stimuli(MWT)and paw withdrawal latency to thermal nociceptive stimulus(TWL)at 1 day before operation and 1,3,7 and 14 days(T1-4) after CCI,and then the six rats in each group were sacrificed,and their lumbar segments(L4-6)of the spinal cord were immediately removed for determination of GLT-1 and GLAST expression in spinal dorsal horn(by real-time fluorescent quantitative PCR).Results:Compared with group S,PWT was "significantly decreased,PWL was shortened,the expression of GLT-1 and GLAST mRNA in group NP was up-regulated on T1 and T2,the expression of GLT-1 and GLAST mRNA in group SIN was up-regulated from T1 to T3(P<0.05).Compared with group NP,PWT was increased remarkablely,PWL was prolonged,the expression of GLT-1 and GLAST mRNA was up-regulated from T1 to T3 in group SIN(P<0.05).Conclusion:SIN can mitigate neuropathic pain in rats and the possible mechanism may be its up-regulating effect on spinal GLT-1 and GLAST mRNA expression.