基于PI3K-Akt-mTOR信号通路探讨葛根素对大鼠神经病理性疼痛的影响

Protective effect of puerarin on neuropathic pain in rats based on the PI3K-Akt-mTOR pathway

目的基于PI3K-Akt-mTOR信号通路探讨葛根素对大鼠神经病理性疼痛的作用。方法取8只SD大鼠作为假手术组,将24只采用压迫损伤坐骨神经方法构建的神经病理性疼痛模型大鼠随机分为模型组、葛根素组、PI3K抑制剂组各8只。葛根素组给予葛根素注射液100 mg/kg腹腔注射,PI3K抑制剂组给予wortmannin 5 mg/kg腹腔注射,假手术组和模型组给予等量的生理盐水腹腔注射,均每天1次,连续1周。检测各组大鼠坐骨神经机械刺激缩足反射阈值、热缩足反射潜伏期以及冷缩足反射阈值,对L4~6段脊髓进行HE染色以及原位末端标记(TUNEL)检测,采用Western blot法检测各组大鼠脊髓组织中PI3K、Akt、mTOR蛋白表达水平。结果模型组大鼠的机械刺激缩足反射阈值和热缩足反射潜伏期均显著低于假手术组(P均<0.05),冷缩足反射阈值显著高于假手术组(P<0.05);葛根素组和PI3K抑制剂组大鼠的机械刺激缩足反射阈值和热缩足反射潜伏期均显著高于模型组(P均<0.05),冷缩足反射阈值均显著低于模型组(P均<0.05)。模型组大鼠脊髓组织细胞凋亡率和脊髓组织中PI3K、Akt、mTOR蛋白表达水平均显著高于假手术组(P均<0.05),葛根素组和PI3K抑制剂组脊髓组织细胞凋亡率和脊髓组织中PI3K、Akt、mTOR蛋白表达水平均显著低于模型组(P均<0.05)。葛根素组和PI3K抑制剂组各指标比较差异均无统计学意义(P均>0.05)。结论葛根素具有改善大鼠神经病理性疼痛的作用,作用机制可能与PI3K-Akt-mTOR信号通路密切相关。

Objective It is to investigate the effect of puerarin on neuropathic pain in rats based on PI3K-Akt-mTOR signaling pathway.Methods Eight SD rats were taken as the sham operation group,and 24 neuropathic pain model rats constructed by compressing the sciatic nerve were randomly divided into a model group,a puerarin group,and a PI3K inhibitor group with 8 rats in each group.The puerarin group was given puerarin injection 100 mg/kg by intraperitoneal injection,PI3K inhibitor group was given wortmannin 5 mg/kg by intraperitoneal injection,sham operation group and model group were given the same amount of normal saline by intraperitoneal injection,all the groups were treated once a day for 1 week.The the mechanical stimulation foot reflex threshold,thermal foot reflex shrinkage latency and cold foot reflex threshold of the sciatic nerve in each group of rats were measured.HE staining and TUNEL detection were performed on segment L4-L6 spinal cord.Western blot was used to detect the protein levels of P13K,Akt and mTOR in spinal cord tissues of rats in each group.Results Compared with sham operation group,the thermal shrinkage reflex latency and mechanical stimulation foot reflex threshold of the rats in the model group was significantly decreased(P<0.05),cold foot reflex threshold was increased significantly(P<0.05).Meanwhile,the thermal foot reflex shrinkage latency and mechanical stimulation foot reflex threshold of the puerarin group were significantly higher than those in the model group(P<0.05),cold foot reflex threshold was significantly lower than that in the model group(P<0.05).The apoptosis rate and the protein expressions of P13K,Akt and downstream kinase mTOR were significantly higher in the model group than those in the sham operation group(P<0.05).The apoptosis rate and the protein expressions of P13K,Akt and downstream kinase mTOR were significantly lower in the puerarin group and PI3K inhibitor group than those in the model group(P<0.05),but there was no significant difference in these indexes between puerarin group and PI3K inhibitor group.Conclusion Puerarin can improve neuropathic pain in rats,and the mechanism may be closely related to the PI3K-Akt-mTOR signaling pathway.