鞘内给予氯胺酮通过抑制星形胶质细胞内STAT3的磷酸化改善大鼠神经病理性痛的研究

The inhibition of phosphorylation of astrocytic STAT3 alleviates neuropathic pain in rat via intrathecal injection of ketamine

目的:观察神经病理性痛大鼠鞘内给予氯胺酮对于脊髓背角星形胶质细胞内信号转导和转录活化因子3(STAT3)磷酸化水平的影响。方法:采用L5脊神经结扎(SNL)方法制作慢性神经病理性痛模型,利用机械刺激法和热板法连续观察造模后大鼠的痛行为变化;应用免疫组织化学染色和Western Blot方法观察大鼠腰膨大节段胶质纤维酸性蛋白(GFAP)和磷酸化STAT3(pSTAT3)的表达水平。结果:SNL模型大鼠机械性痛阈和热痛阈均明显降低,且术后一周内均保持在较低的水平(P<0.01),从术后第3 d起鞘内连续给予氯胺酮至第7 d能够明显缓解大鼠患侧后爪的机械性痛敏和热痛敏。免疫荧光组织化学染色显示:pSTAT3在星形胶质细胞上有表达,且SNL后pSTAT3与GFAP在脊髓背角的表达均升高。Western Blot结果显示:与对照组相比,SNL后第7 d脊髓背角的pSTAT3的表达明显上调(P<0.05),从术后第3 d鞘内连续给予氯胺酮至第7 d能够明显下调STAT3的磷酸化水平。结论:鞘内给予氯胺酮能够明显下调脊髓背角星形胶质细胞内STAT3的磷酸化水平从而达到缓解疼痛的目的。

Objective：To observe the effect of intrathecal injection of ketamine on the neuropathic pain by inhibition of the phosphorylation of astrocytic signal transducer and activator of transcription 3（STAT3）.Methods：Chronic neuropathic pain model was built by left L5 spinal nerve ligation（SNL） in rats,von Frey filament and hot plate tests were used to investigate the mechanical and thermal allodynia.Immunofluorescent histochemistry and Western Blot was applied to analyze the expression level of glial fibrillary acidic protein（GFAP） and pSTAT3 in spinal dorsal horn in lumbar enlarge segment after SNL.Results：Compared with sham group,the paw withdrawal threshold（PWT） and paw withdrawal latency（PWL） was significantly decreased（P 〈0.01）,and the mechanical and thermal allodynia was obviously attenuated after intrathecal administration of ketamine from post operation 3 d to 7 d.Immunofluorescent histochemical staining showed that pSTAT3 was expressed in astrocytes and the higher expression of GFAP and pSTAT3 after SNL.Western Blot results revealed that the expressions of both GFAP and pSTAT3 in spinal dorsal horn were significantly increased on post operational 7 d compared with the sham group（P〈 0.05）.And then,intrathecal administration of ketamine can inhibit the phosphorylation of astrocytic STAT3.Conclusion：Intrathecal injection of ketamine could inhibit the phosphorylation of astrocytic STAT3 obviously,so as to achieve the purpose of relieving neuropathic pain.