慢性坐骨神经结扎神经痛大鼠脊髓nNOS阳性神经元的表达

THE EXPRESSION OF nNOS ON THE SPINAL CORD OF THE RATS FOLLOWING CHRONIC CONSTRICTION INJURY OF THE SCIATIC NERVE

目的:探讨慢性坐骨神经结扎(CCI)神经病理性疼痛大鼠脊髓背角nNOS阳性神经元的表达。方法:SD大鼠40只,随机分为五组,每组8只,即naive组、sham组、CCI5d组、CCI10d组;CCI15d组;测定各组大鼠机械缩腿阈值(MWT)和热缩腿潜伏期(TWL);同时sham组大鼠在术后5d、CCI各组分别在术后5d、10d、15d断头处死取脊髓腰膨大,采用免疫组化法测定脊髓背角nNOS阳性神经元的表达。结果:CCI大鼠在手术后形成稳定的痛敏,与naive组和sham组大鼠比较有显著差异;naive组大鼠和sham组大鼠脊髓背角仅见少量nNOS阳性神经元的表达,且两组间无统计学意义;CCI各组大鼠脊髓背角nNOS阳性神经元的表达明显增多,与naive组和sham组比较差异显著。结论:慢性坐骨神经结扎(CCI)神经痛大鼠脊髓背角nNOS阳性神经元的表达增加,脊髓背角nNOS可能参与了CCI大鼠神经病理性疼痛的形成。

Objective：To investigate the expression of nitric oxide synthase（nNOS） on the spinal cord of the rats following chronic constriction injury（CCI） of the sciatic nerve.Methods：Forty male Sprague-Dawley rats weighting 200～220 g were randomly divided into five groups（n=8）：naive group;sham operation group;CCI 5 d group;CCI 10 d group;CCI 15 d group.The mechanical withdrawal threshold（MWT） and thermal withdrawal latency（TWL） of rats in each group were measured by Von Frey hair and radiant thermal stimulator respectively.The expression of nNOS on the spinal cord of the rats in each group was detected with immunohistochemical staining at the 5th d,10th d,15th d after operation,and the number of the nNOS positive neurons was counted under microscope.Results：MWT and TWL of the rats in CCI 5d group;CCI 10d group;CCI 15d group were decreased significantly compared to the rats in naive group and sham group.The expression of nNOS on the spinal cord of the rats in CCI groups was markedly increased compared with naive group and sham group.Conclusion：These data shows that nNOS-positive neurons increase on the spinal cord of the rats following chronic constriction of sciatic nerve,the nNOS in the spinal cord possibly involves in the CCI-induced mechanical and thermal hyperalgesia.