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 ThroughModulating the Voltage-gated Sodium and Potassium Current in DRGNeurons in Rats of Spared Sciatic Nerve Injury

Objective:To evaluate the effect of ginsenoside Rd on the mechanical pain hypersensitivity in rats with spared sciaticnerve injury and probe the potential underlying mechanism.Methods:7 day post SNI, the paw withdrawl mechanical threshold wasmeasured before and after intraperitoneal administration of ginsenoside Rd in rats with mechanical pain hypersentivity; the L4 and L5DRG 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 thevoltage-gated potassium current in small- and medium-sized DRG neurons in rats with SNI.Conclusion:Ginsenoside Rd could reversedthe mechanical pain hypersensitivity in rats with SNI, and the potential mechanism might relate to the modulating effect of ginsenosideRd on the voltage-gated sodiumcurrent and the voltage-gated potassiumcurrent.