大黄素抑制背根神经节压迫小鼠模型STAT3、VEGFA、p-ERK蛋白表达及其镇痛作用研究

Inhibition of emodin on STAT3,VEGFA,and p-ERK protein expressions in mouse model of dorsal root ganglion compression and its analgesic effect

目的 研究大黄素(Emodin,ED)对背根节压迫小鼠模型的镇痛作用以及对STAT3/VEGFA/p-ERK信号通路的影响。方法 建立背根神经节慢性压迫(chronic compression damage,CCD)小鼠疼痛模型,随机分为空白组、模型组、普瑞巴林组及ED低、中、高剂量组。通过检测动物机械痛敏和热辐射痛敏阈值、醋酸扭体实验评价镇痛效果;ELISA检测小鼠L4-L5节段脊髓组织中白细胞介素-6(interleukin-6,IL-6)、肿瘤坏死因子(tumor necrosis factor-α,TNF-α)和CD18等炎症因子含量;Western blot和免疫荧光检测脊髓组织信号转导子和转录激活子3(signal transducer and activator of transcription 3,STAT3)、血管内皮生长因子(vascular endothelial growth factor,VEGF)和磷酸化细胞外信号调节激酶(phosphorylated extracellular signal-regulated kinases 1/2,p-ERK1/2)蛋白表达。结果 与空白组比较,模型组的机械痛敏、热辐射痛敏阈值显著降低(P<0.05),脊髓背角炎症因子表达显著增高(P<0.05),脊髓中VEGFA、STAT3、p-ERK的表达显著上调(P<0.05)。与模型组比,ED低、中、高剂量组CCD小鼠模型的机械痛敏、热辐射痛敏阈值升高(P<0.05);脊髓背角炎症因子表达降低(P<0.05);脊髓背角小胶质细胞STAT3、VEGFA、p-ERK的表达降低(P<0.05),醋酸诱导的小鼠急性疼痛中扭体次数减少(P<0.05)。结论 ED对背根节压迫小鼠模型有良好的镇痛作用,其机制可能与抑制脊髓背角炎症因子表达和STAT3/VEGFA/p-ERK介导的脊髓小胶质细胞活化有关。

Objective To study the analgesic effect of emodin(ED) on dorsal root ganglion compression mouse model and its impact on STAT3/VEGFA/p-ERK signaling pathway.Methods A chronic compression damage(CCD) pain mice model was established and the mice were randomized into blank group,model group,pregabalin group,low-,medium-,and high-dose ED groups.The mechanical and thermal radiation pain sensitivity thresholds of the animals were measured,and the analgesic effect was evaluated using the acetic acid writhing test;the levels of inflammatory factors such as Interleukin-6(IL-6),tumor necrosis factor-α(TNF-α),and CD18 in the spinal cord of mice at L4-L5 levels were checked by ELISA;the protein expressions of signal transducer and activator of transcription 3(STAT3),vascular endothelial growth factor(VEGF),and phosphorylated extracellular signal-regulated kinases 1/2(p-ERK1/2) in the spinal cord were determined by Western blot and immunofluorescence.Results Compared with the blank group,the model group showed significantly decreased mechanical and thermal radiation pain sensitivity thresholds,as well as significantly increased expression of inflammatory factors in the spinal dorsal horn(P<0.05),and the expressions of VEGFA,STAT3,and p-ERK in spinal cord were significantly up-regulated(P<0.05).Compared with the model group,the low-,medium-,and highdose ED groups of the CCD mouse model exhibited increased mechanical and thermal radiation pain sensitivity thresholds(P<0.05),decreased expression of inflammatory factors in spinal dorsal horn(P<0.05),reduced expressions of STAT3,VEGFA,and p-ERK in spinal dorsal horn microglia(P<0.05),and a decreased number of writhing in acute pain induced by acetic acid in mice(P<0.05).Conclusion ED has a good analgesic effect on dorsal root ganglion compression mouse model,and its mechanism may be related to the inhibition of inflammatory factor expression in the spinal dorsal horn and the activation of spinal microglia mediated by STAT3/VEGFA/p-ERK.