鞘内注射ω-芋螺毒素SO3对CCI大鼠脊髓及坐骨神经iNOS蛋白表达的影响

Effect of intrathecal injection of ω-conopeptide SO3 on inducible nitric oxide synthase expression in spinal cord and chronically constricted sciatic nerve in rat

目的通过检测鞘内注射ω-芋螺毒素SO3对坐骨神经慢性挤压伤(CCI)模型大鼠脊髓及坐骨神经诱生型一氧化氮合酶(iNOS)蛋白表达的影响,探讨慢性神经痛发展过程中Ca2+对iNOS的作用。方法雄性SD大鼠40只,随机分为4组(n=10):N组为正常对照组,C组为CCI后14天组,CN组为CCI7天后连续鞘内注射生理盐水7天组,CS组为CCI7天后连续鞘内注射ω-芋螺毒素SO3(30ng/h)7天组。用Western blot方法检验各组动物脊髓及坐骨神经结扎部位中段和远端iNOS蛋白表达量的变化。以GAPDH表达量作为内参照。结果正常大鼠脊髓及坐骨神经标本未见iNOS表达,CCI大鼠结扎侧坐骨神经及同侧脊髓均有较强的iNOS表达,持续鞘内注射ω-芋螺毒素SO3后此种表达减弱。结论CCI大鼠脊髓和受损坐骨神经iNOS表达增加,鞘内注射ω-芋螺毒素SO3可降低CCI大鼠上述部位iNOS表达。在慢性神经痛的发展过程中,Ca2+通道阻滞剂对iNOS的表达有一定作用。

Objective To evaluate the effect of intrathecal administration of ω-conopeptide SO3 on inducible nitric oxide synthase （iNOS） expression of spinal cord and the ligated sciatic nerve in a rat model with chronic constriction injury （CCI）. Methods 40 male SD rats were randomly divided into 4 groups of 10 animals each. Rats in the N group served as controls; in group C 4 loose ligatures were placed around the right sciatic nerve for 14 days; in group CN, normal saline 1μl/h was injected intrathecally slowly for 7 days seven days after the ligation; in group CS, ω-conopeptide SO3 30ng/h was administered intrathecally slowly for 7 days seven days after the ligature. Local expression of iNOS was assayed in samples taken from injured nerves （between and distal to the CCI site） and the spinal cord using Western blotting analysis, with GAPDH as an internal reference. Results A 130 kDa band, corresponding to iNOS protein was detected in the middle and distal sections of the injured nerves and the spinal cord. The iNOS immunoreactivity was inhibited by continuous intrathecal injection of ω-conopeptide SO3. There was no difference in the expression of iNOS between group CN and group C. Conclusion The expression of iNOS in the spinal cord and injured nerves of CCI rats was enhanced. Intrathecal injection of ω-conopeptide SO3 can inhibit the expression of iNOS. The data suggested that N-type calcium channel blocker took part in the expression of iNOS.