人参皂甙Rd通过调节SNI大鼠背根神经节钠、钾电流抑制痛敏

目的：观察人参皂甙Rd（ginsenoside Rd）对大鼠坐骨神经分支选择性损伤（spared sciatic nerve injury,SNI）引起的痛敏的影响及其作用机制。方法：坐骨神经分支选择性损伤术后7天,观察腹腔注射不同浓度人参皂甙Rd后大鼠后足的机械性缩足反应阈值（paw withdrawl mechanical threshold,PWMT）的变化;在术后7天,急性分离并取出大鼠腰4和腰5段背根节,对整节DRG上的中小型神经元运用全细胞膜片钳技术进行记录。结果：坐骨神经分支选择性损伤术后7天,大鼠出现明显的机械性痛敏,腹腔注射5 mg/ml和10 mg/ml的人参皂甙Rd能剂量依赖性的翻转大鼠机械性痛敏;坐骨神经分支选择性损伤能明显地增大SNI大鼠DRG中小型神经元上的钠电流以及减小电压依赖性钾电流,而100μM人参皂甙Rd能有效翻转该钠、钾电流的变化。结论：人参皂甙Rd能有效地改善坐骨神经分支选择性损伤引起的机械性痛敏,其机制可能与人参皂甙Rd明显地调节SNI大鼠DRG中小型神经元上的电压依赖性钠、钾电流有关。

Ginsenoside Rd Inhibits Mechanical Pain Hypersensitivity Through Modulating the Voltage-gated Sodium and Potassium Current in DRG Neurons in Rats of Spared Sciatic Nerve Injury

Objective：To evaluate the effect of ginsenoside Rd on the mechanical pain hypersensitivity in rats with spared sciatic nerve injury and probe the potential underlying mechanism.Methods：7 day post SNI,the paw withdrawl mechanical threshold was measured before and after intraperitoneal administration of ginsenoside Rd in rats with mechanical pain hypersentivity;the L4 and L5 DRG were isolated acutely,and whole-cell recording patch clamp were performed on small- and medium-sized DRG neurons.Results：Ginsenoside Rd could dose-dependently reduce mechanical pain hypersentivity induced by spared sciatic nerve injury;electrophysiological recordings showed that ginsenoside Rd could decrease the voltage-gated sodium current and increase the voltage-gated potassium current in small- and medium-sized DRG neurons in rats with SNI.Conclusions：Ginsenoside Rd could reversed the mechanical pain hypersensitivity in rats with SNI,and the potential mechanism might relate to the modulating effect of ginsenoside Rd on the voltage-gated sodium current and the voltage-gated potassium current.