17β-雌二醇对大鼠神经病理性疼痛阈值的影响

Effects of 17β-estradiol on threshold of rat neuropathic pain

目的探讨17β-雌二醇对神经病理性大鼠疼痛阈值的影响。方法 SD雌性大鼠50只,采用随机数字表法分5组,假手术组(分离暴露左侧坐骨神经但不结扎,注射生理盐水),其余4组建立坐骨神经慢性压榨损伤(CCI)模型,CCI组(注射生理盐水),雌二醇组(注射17β-雌二醇),拮抗剂组(注射AP-5),复合组(注射17β-雌二醇+AP-5),每组10只。采用机械刺激缩足反射阈值(PWMT)检测大鼠的机械痛阈值,热刺激缩足反射潜伏期(PWTL)检测大鼠的热痛阈值,免疫组织化学法和Western blot法测定脊髓背根神经节N-甲基-D-天冬氨酸受体1(NMDARl)蛋白的表达。结果与假手术组比较,CCI组和雌二醇组大鼠PWMT降低(P<0.05),PWTL缩短(P<0.05),NMDARl蛋白的表达显著增加(P<0.05)。与CCI组比较,雌二醇组大鼠PWMT降低(P<0.05),PWTL缩短(P<0.05),NMDARl蛋白的表达显著增加(P<0.05)。结论 17β-雌二醇可以通过增加NMDARl的表达,降低神经病理性大鼠的疼痛阈值。

Objective To investigate the effect of 17β-estradiol on the pain threshold in neuropathic rats.Methods Fifty female SD rats were divided into five groups by adopting the random number table method,the sham operation group(separating and exposing the left sciatic nerve without ligation and giving the saline injection),the other four groups were established as chronic compression injury(CCI)model of sciatic nerve:CCI group(saline injection),estradiol group(17β-estradiol injection),antagonist group(AP-5 injection)and composite group(17β-estradiol and AP-5 injection),10 cases in each group.The rat mechanical pain threshold value was examined by adopting the paw withdrawal mechanical threshold(PWMT),the rat thermal threshold was examined by adopting the paw withdrawal thermal latency(PWTL),and the expression of NMDAR1 protein was determined by immunohistochemistry and Western blot.Results Compared with the sham operation group,PWMT in the CCI group and estradiol group was decreased(P<0.05)and PWTL was shortened(P<0.05),while the expression of NMDAR1 protein was significantly increased(P<0.05).Compared with the CCI group,PWMT in the estradiol group was decreased(P<0.05)and PWTL was shortened(P<0.05),while the expression of NMDAR1 protein was significantly increased(P<0.05).Conclusion 17β-estradiol can decrease the pain threshold of the neuropathic pain rats by increasing the NMDAR1 expression.