聚焦式低强度脉冲超声治疗对大鼠坐骨神经损伤后神经病理性疼痛的影响

Effects of focused low-intensity pulsed ultrasound treatment on neuropathic pain after sciatic nerve injury in rats

目的:观察聚焦式低强度脉冲超声(focused low-intensity pulsed ultrasound,FLIPUS)对坐骨神经损伤模型(spared nerve injury,SNI)大鼠的镇痛作用,以及对脊髓神经重塑的影响。方法:建立SNI神经病理性疼痛大鼠模型。将30只雄性SD大鼠随机分成3组,假手术组、模型组和治疗组各10只。治疗组大鼠造模后第3天开始脊髓腰膨大FLIPUS治疗,分别于术前、术后3、10、17、24、30天测量各组大鼠患侧后爪机械性刺激缩爪阈,采用Western Blot与免疫荧光技术检测脊髓神经突起标志物(MAP2)蛋白的表达水平。结果:SNI大鼠术后第3天开始患侧后爪明显下降且至少维持至术后第30天(P<0.01),提示出现机械痛觉过敏;FLIPUS治疗组SNI大鼠术后第10天机械性刺激缩爪阈开始升高,在术后第24和30天机械性刺激缩爪阈显著高于模型组(P<0.01);SNI大鼠术后脊髓MAP2蛋白表达显著上调(P=0.004),而FLIPUS治疗可显著降低治疗组脊髓MAP2蛋白的表达量(P<0.01)。结论:FLIPUS可缓解SNI诱导的机械痛敏症状,其机制可能与抑制脊髓的神经重塑有关。

Objective:To observe the analgesic effect of focused low-intensity pulsed ultrasound(FLIPUS) on spared nerve injury model(SNI) rats and its effect on spinal nerve remodeling.Method:Establish a rat model of SNI neuropathic pain. Thirty male SD rats were randomly divided into 3 groups: the sham operation group,the model group and the treatment group(10 rats in each group). The rats in the treatment group started the FLIPUS treatment of spinal lumbar enlargement at the 3rd day after the modeling,and the paw withdrawal threshold of the affected hind paw was measured before and 3, 10, 17, 24,and 30 days after the operation. Western Blot and immunofluorescence techniques were used to detect the level of spinal cord neurite marker(MAP2) protein.Result:The paw withdrawal threshold of the hind paw on the affected side of SNI rats decreased significantly at the 3rd day after surgery and maintained at least until the 30th day after surgery(P<0.01),indicating mechanical hyperalgesia. The paw withdrawal threshold of the SNI rats in the FLIPUS treatment group exhibited increased trend at the 10th day after the operation,and the paw withdrawal threshold was significantly higher than that of the model group at the 24th and 30 th day after the operation(P<0.01). The expression of MAP2 protein in the spinal cord of SNI rats was significantly up-regulated(P=0.004), and FLIPUS treatment could significantly reduce the expression of MAP2 protein in the spinal cord of the treatment group(P<0.01).Conclusion:FLIPUS can alleviate the symptoms of mechanical hyperalgesia induced by SNI,and its mechanism may be related to the inhibition of spinal cord nerve remodeling.