经典瞬时感受器电位通道在炎性痛及神经病理性痛大鼠背根神经节表达水平的差异

目的 探讨背根神经节细胞经典瞬时感受器电位通道家族（TRPC）各亚型在炎性痛及神经病理性痛中表达是否存在差异性.方法 选用Sprague-Dawley雄性大鼠,随机分为两大组：炎性痛组和神经病理性痛组.炎性痛组又随机分为：空白对照组,生理盐水对照组,蜜蜂毒炎性痛模型组;神经病理性痛组又随机分为：空白对照组,假手术组,坐骨神经分支选择性结扎模型组.测定各组大鼠机械刺激缩足反射阈值和热刺激缩足潜伏期;然后分别于蜜蜂毒处理后2h及神经结扎后1周,检测各组大鼠背根神经节细胞内TRPC家族各亚型mRNA表达水平和各组背根神经节细胞内TRPC家族相应亚型蛋白表达水平.结果 实时定量基因扩增荧光检测技术显示,背根神经节细胞TRPC3、4、5亚型的mRNA表达水平在蜜蜂毒炎性痛组显著增加（P＜0.001）;而在神经病理性痛组背根神经节细胞TRPC2 mRNA表达水平显著提高（P ＜0.001）,同时TRPC3 mRNA表达水平却显著降低（P＜0.05）.免疫组化结果显示蜜蜂毒炎性痛组大鼠背根神经节内TRPC3、4、5免疫阳性细胞数显著增加;而神经病理性痛组大鼠背根神经节内TRPC2免疫阳性细胞数显著增加.结论 蜜蜂毒炎性痛模型及坐骨神经分支选择性结扎模型大鼠背根神经节细胞TRPC通道各亚型基因及蛋白表达水平存在差异,提示TRPC通道各亚型在炎性痛及神经病理性痛的发病中可能发挥着不同的作用.

Differential mRNA expression levels of transient receptor potential canonical subtype in dorsal root ganglion of inflammatory pain rats and neuropathic pain rats

Objective To investigate whether the transient receptor potential canonical （TRPC） subtype expression level difference between inflammatory pain and neuropathic pain in dorsal root ganglion cell.Methods Male Sprague-Dawley rats were randomly divided into two groups：inflammatory pain group （rats in which were randomly divided into blank saline group,Bee Venom-induced inflammatory pain group） and neuropathic pain group （rats in which were randomly divided into blank sham operation group,spared nerve injury group）.Measuring paw withdrawal thermal latency （s） and paw withdrawl mechanical threshold （g）.The L4-5 dorsal root ganglion of different groups were obtained at different times （Bee Venom-induced inflammatory pain group 2 h after injection of Bee Venom,nerve injury group 1 w after nerve injury） and then the mRNA and protein expression levels of TRPC subtype were detected.Results Real-time quantitative PCR detecting found that the mRNA expression levels of TRPC3,4,5 were significantly increased along with the others remaining almost unchanged in Bee Venom-inflammatory rats （P ＜ 0.001）.While,in the rats with neuropathic pain,the mRNA expression level of TRPC2 was significantly increased （P ＜ 0.001） along with a significant decrease in the mRNA expression level of TRPC3 （P ＜ 0.05）.The results of immunohistochemistry and immunofluorescence showed that the number of dorsal root ganglion cells immunoreactive TRPC3,4,5 significant increased in bee venom inflammatory pain rats; whereas neuropathic pain group TRPC2 immunoreactive cells were significantly increased in rat dorsal root ganglion.Conclusion There were some differences in TRPC subtype mRNA and protein expression level in dorsal root ganglion neurons between Bee Venominflammatory pain and spared nerve injury neuropathic pain,which hinted that different TRPC subtype channels may play distinct role in the onset of inflammatory pain and neuropathic pain.