LAUSR

Objective To observe the effects of electroacupuncture (EA) of different frequencies on transmission function, electromyography, nitric oxide synthase (NOS) content and interstitial cells of Cajal (ICC) expression of colon in rat models with slow transit constipation (STC). Methods Of the 50 healthy male Wistar rats, 10 were randomly selected as a normal group and fed with ordinary diet, and the remaining 40 rats were fed with the diet added with the compound diphenoxylate at a dose of 8 mg/(kg·bw) each day for continuous 120 d. The 40 successfully established STC rat models were randomly divided into a model group, a low-frequency EA group (2 Hz), a high-frequency EA group (100 Hz), and a variable-frequency EA group (2 Hz/100 Hz), with 10 rats in each group. Rats in the normal and the model groups were not given any treatment; the low-frequency EA and the high-frequency EA groups were given EA at Tianshu (ST 25), Zusanli (ST 36) and Zhigou (TE 6) with continuous wave at the designated frequency, and the variable-frequency EA group received sparse-dense wave (2 Hz/100 Hz) EA at the same acupoints, once a day for a total of 15 d. After treatment, the colonic transmission function, electromyography, NOS content and ICC expression (calculated by the difference in the area of the C-kit positive cells) of the rats in each group were measured. Results For the colonic transmission function, compared with the normal group, the first black stool excretion durations of rats in the other groups were significantly prolonged (all P <0.05); compared with the model group, the first black stool excretion durations of rats in the three EA groups were significantly shortened (all P <0.05), which was significantly shorter in the variable-frequency EA group than in the low-frequency EA and high-frequency EA groups (both P <0.05). For the colonic electromyography, compared with the normal group, the amplitude was significantly increased and the frequency was accelerated in rats of the other groups (all P <0.05); compared with the model group, the amplitude was significantly reduced and the frequency was slowed down in the three EA groups (both P <0.05); compared with the low-frequency EA and the high-frequency EA groups, the amplitude was reduced and the frequency was significantly reduced in rats of the variable-frequency EA group (both P <0.05). Compared with the normal group, the colonic NOS contents were significantly increased in the other groups (all P <0.05); compared with the model group, the NOS contents were significantly reduced in the three EA groups (all P <0.05); compared with the low-frequency EA and the high-frequency EA groups, the content was significantly reduced in the variable-frequency EA group (all P <0.05). For the area of rat colonic C-kit-positive cells, compared with the normal group, the areas were significantly reduced in rats of other groups (all P <0.05); compared with the model group, the areas were increased significantly in the three EA groups (all P <0.05); compared with the low-frequency EA group, the area was increased significantly in the variable-frequency EA group ( P <0.05). Conclusion EA, especially EA at the 2 Hz/100 Hz variable-frequency, has a positive treatment effect on the STC model rats. It may improve rats’ colonic function by regulating the electromyography, NOS content and ICC expression of colon. 目的 观察不同频率电针对慢传输型便秘(STC)模型大鼠肠道传输功能、结肠肌电、结肠一氧化氮合酶(NOS) 含量和大鼠Cajal间质细胞(ICC)表达的影响. 方法 选择健康雄性Wistar大鼠50只, 随机选取10只为正常组, 饲以普通饲料, 其余40只在饲料中添加复方苯乙哌啶, 剂量为每日8 mg/(kg·bw), 连续给药120 d, 40只大鼠均成功建立 STC大鼠模型, 并随机分为模型组、低频电针组(频率为2 Hz)、高频电针组(频率为100 Hz)和变频电针组(频率为 2 Hz/100 Hz), 每组10只.正常组和模型组不进行任何治疗, 低频电针组和高频电针组分别给予相应频率的连续波电针刺激天枢、足三里和支沟, 变频电针组接受相应频率的疏密波电针刺激相同穴位, 每日1次, 共治疗15 d.治疗后测定各组大鼠肠道传输功能、结肠肌电、结肠NOS含量和结肠C-kit阳性细胞面积, 以面积的数值差异来表示 ICC的表达. 结果 在 肠道传输功能方面, 与正常组大鼠比较, 其余各组大鼠首粒黑便排出时间均明显延长(均 P <0.05); 与模型组比较, 三个电针组大鼠首粒黑便排出时间明显缩短(均 P <0.05); 变频电针组首粒黑便排出时间明显短于低频电针组和高频电针组(均 P <0.05).在结肠肌电方面, 与正常组大鼠比较, 其余各组大鼠结肠肌电振幅明显变大, 频率加快(均 P <0.05); 与模型组比较, 三个电针组的振幅明显缩小, 频率减慢(均 P <0.05); 与低频电针组和高频电针组比较, 变频电针组振幅缩小, 频率明显降低(均 P <0.05).结肠NOS含量方面, 与正常组大鼠比较, 其余各组大鼠NOS含量明显增加(均 P <0.05); 与模型组比较, 三个电针组NOS含量明显降低(均 P <0.05); 与低频电针组和高频电针组比较, 变频电针组NOS含量明显降低(均 P <0.05).各组大鼠结肠C-kit阳性细胞面积方面, 与正常组大鼠比较, 其余各组大鼠C-kit阳性细胞面积明显减少(均 P <0.05).与模型组比较, 三个电针组C-kit阳性细胞面积明显增加(均 P <0.05); 与低频电针组比较, 变频电针组C-kit阳性细胞面积明显增大( P <0.05). 结论 电针, 特别是2 Hz/100 Hz变频电针治疗STC模型大鼠疗效肯定, 可能是通过调节大鼠结肠肌电、结肠NOS含量和ICC表达改善其肠道功能.