脉冲射频对大鼠痛行为及背根神经节电压门控性钠离子通道的影响

THE EFFECT OF PULSED RADIOFREQUENCY ON PAIN BEHAVIOR AND FUNCTION OF VOLTAGEGATED SODIUM CHANNELS OF DORSAL ROOT GANGLION NEURONS IN NAIVE RATS

目的：探讨脉冲射频（pulsed radiofrequency,PRF）对正常大鼠痛行为的影响以及对背根神经节（dorsal root ganglion,DRG）神经元电压门控性钠离子通道（voltage-gated sodium channels,VGSC）的电流密度和动力学特性的影响。方法：80~100 g雄性SD大鼠63只,随机分为对照组,sham组及PRF组。对照组不做任何处理,将sham组及PRF组大鼠经腹腔麻醉后暴露其右侧坐骨神经,PRF组坐骨神经接受2 Hz,2 min,42℃的脉冲射频处理,而sham组不接受脉冲射频处理。在脉冲射频前2 h,脉冲射频后1 d,3 d,5 d,7 d分别测定各组大鼠的机械刺激缩足反射阈值（paw withdrawal mechanical threshold,PWMT）和热辐射缩足反射潜伏期（paw withdrawal thermal latency,PWTL）。脉冲射频后1 d取L4~5段DRG细胞,应用单细胞膜片钳技术检测大鼠DRG细胞钠电流密度和动力学特性的改变。结果：sham组和PRF组大鼠术后不同时间点的PWMT值和PWTL值与自身手术前的基础阈值相比无差异,各组大鼠之间相同时间点的PWMT值和PWTL值均无统计学差异。PRF组大鼠DRG细胞电压依赖性钠电流密度、半数激活电压（V1/2act）、半数失活电压（V1/2inact）与sham组和对照组相比也均无显著差异。结论：该参数的脉冲射频未影响正常大鼠痛行为。DRG神经元钠电流密度以及通道动力学特性也未受该参数脉冲射频的影响,提示该参数的脉冲射频可能并不影响大鼠生理状态下伤害性感觉传导功能。

Objective： To investigate the effect of pulsed radiofrequency（PRF） on pain behavior as well as the current density and kinetic properties of the voltage-gated sodium channels（VGSC） in dorsal root ganglion（DRG） neurons in naive rats. Methods： Sixty-three male SD rats weighing 80~100 g were randomly divided into control, sham, and PRF groups. The rats in control group received no treatment. The right sciatic nerves of rats in sham group and PRF group were exposed after intraperitoneal anesthesia, then the rats in PRF group received PRF treatment of 2 Hz, 2 min, 42℃. Paw withdrawal mechanical threshold（PWMT） and paw withdrawal thermal latency（PWTL） were measured 2 h before and 1, 3, 5, and 7 days after PRF operation. At day 1 after PRF treatment, L4~5 DRG neurons were collected for whole-cell patch clamp recordings to examine the current densities and kinetic properties of VGSCs. Results： Compared with the basic foot withdrawal threshold before the operation, there was no significant difference of PWMT and PWTL at the different time points measured. There was no significant difference in PWMT and PWTL among each group at the same time point, also, the current densities and kinetic properties in three groups were not changed in DRG neurons after PRF treatment. Conclusion： PRF treatment didn＇t produce any measurable effects on PWMT and PWTL as well as the current density and kinetic property of VGSCs, indicating that PRF treatment with the parameters may not influence nociceptive sensory conduction in naive rats.