糖尿病大鼠周围神经病变时神经电生理及病理变化的关系

Relationship between electrophysiologic and pathologic changes in diabetic peripheral neuropathy rats

目的探讨糖尿病周围神经病变(DPN)时神经电生理改变与病理变化的关系以及病理、神经电生理检查对DPN诊断的意义。方法24只健康雄性SD大鼠经链脲佐菌素一次性腹腔注射方法诱导成DPN模型后,随机分为模型组,大、小剂量药物治疗组,后两组动物分别以通络方剂0.5g/kg和2g/kg加2ml双蒸水配制成的溶液灌胃治疗8周,另设正常对照组(n=8)。8周后检测运动神经传导速度(MCV)、感觉神经传导速度(SCV)及潜伏期、神经电位波幅的变化,并进行病理检查。结果与正常对照组比较,模型组大鼠尾神经传导潜伏期延长,MCV、SCV减慢,神经电位波幅下降。与对照组相比,大剂量治疗组SCV减慢无显著性,但小剂量治疗组SCV与对照组及大剂量治疗组均有统计学差异(P<0.05)。病理检查显示,模型组有髓纤维阳性面积与髓鞘、轴突面积均较正常对照组减少,治疗组均较模型组显著增加,有髓神经纤维阳性面积和髓鞘面积在各组间的变化趋势与SCV的变化趋势基本一致,但大剂量组髓鞘面积较正常组减小(P<0.05)。结论有髓纤维阳性面积、髓鞘面积是反映DPN病程、疗效的更敏感的病理指标;SCV与髓鞘病理改变的关系密切,可作为临床首选诊断DPN的电生理检测项目,但对亚临床或经足量药物治疗DPN患者的髓鞘病变敏感性尚存在不足。

Objective：To investigate the relationship between electrophysiology and pathology changes in diabetic peripheral neuropathy （DPN） rats and to assess the value of electrophysiology in diagnosis of DPN. Methods： Twenty-four healthy male SD rats were intraperitoneally injected with a single dose of streptozotocin to induce DPN models and the rats were subsequently divided into 3 groups, namely, the DPN model group, the low dose Tong-Luo composite recipe （TLCR） group, and the high dose TLCR group. Rats in the latter 2 groups were lavaged with 2 ml double-distilled water containing 0.5 g/kg and 2 g/kg TLCR for 8 weeks, respectively. Antotber 8 healthy rats were taken as normal controls. The motor conduction velocity （MCV）, sensory conduction velocity （SCV）, and potential latency and amplitude of caudal nerves were measured after 8 weeks in all rats. Morphometric quantitative analysis was also performed. Results.. Compared with normal control group, the MCV, SCV, and potential amplitude of the caudal nerve in DPN model group were decreased, but the potential latency was increased. After TLCR treatment, the above indices were significantly improved and were close to those of the normal control group. SCV of the low dosage group was still significantly lower than that of normal control group （P〈0.05）, that of high dose group was also lower than that of normal control group but with no statistical significance, and that of low dose group was significantly low than that of high dose group （P〈0.05）. Pathological examination showed that the myelinated nerve fiber positive area, myelin sheath area, and axon area in DPN model group were lower than those in the normal control group; the areas in treatment group were obviously increased compared with DPN model group. Compared with the low dose group, the high dose group had significantly larger myelinated nerve fiber positive area and myelin sheath area, but not axon area. The changes of the myelinated nerve fiber positive area and myelin sheath area were basically consistent to SCV changes in all groups, but the myelin sheath area of the high dose group were still smaller than that of the normal control group （P〈0. 05）. Condusion： Myelinated nerve fiber positive area and myelin sheath area are the more sensitive markers of the course and therapeutic outcome of DPN. SCV can be used for initial estimation of myelinated nerve fiber density. SCV is closely related to the pathological changes of myelin sheath and can be used for clinical diagnosis of DPN, but should be reserved for patients with subclinical DPN and patients who have received high dose drug treatment.