[Effect of deep needling "Tianshu" (ST25) on colonic motility in rats with slow transit constipation].

To observe the effect of acupuncture of "Tianshu"(ST25) at different depths on colonic transportation function, expressions of colonic substance P (SP) and interstitial cells of Cajal (ICC) in rats with slow transit constipation (STC), so as to explore its mechanisms underlying improvement of STC．.Fifty male Wistar rats were selected and randomly divided into control，STC model，conventional acupuncture，deep needling group 1 and deep needling group 2 groups，with 10 rats in each group．The STC model was established by gavage of 1 mg/mL compound diphenoxylate suspension (10 mg/kg), once every other day for 21 days, and rats of the control group were given the same dose of distilled water by gavage．EA (2 Hz, 2 mA) was applied to "Tianshu"(ST25), with the acupuncture needle inserted to a depth of 3 mm for rats of the conventional acupuncture group, 4.5 mm for those of deep needling group 1, and 10 mm for those of the deep needling group 2. The acupuncture needle was twirled for 1 min, then retained for 15 min each time, once a day for 15 consecutive days．Following modeling, rats of the 4 groups and the control group received gavage of active carbon 2 mL (100 g/L) for observing the excretion time of the first black stool grain to assess the intestinal transit function. The colonic myoelectric activities (frequency and amplitude) were recorded by using BIOPAC multichannel physiograph. The immunoactivity of SP and c-kit (a transmembrane protein kinase for identification of ICC) of colonic musculature was detected by immunohistochemistry.Compared with the control group，the time of excretion of the first black stool grain, and the amplitude of colonic electromyogram (EMG) were significantly increased (P<0.01), while the frequency of EMG, expressions of SP and c-kit (ICC) were significantly decreased in the model group (P<0.01). In contrast to the model group, both deep needling group 1 and 2 had a decrease in the time of excretion of the first black stool grain, and amplitude of intestinal EMG, and an increase of frequency of intestinal EMG, and immunoactivity of SP and c-kit (P<0.01). The effect of deep needling 2 is superior to that of deep needling 1 in reducing the time of excretion of the first black stool grain (P<0.05), lowering the amplitude of EMG of the gut smooth muscle (P<0.05) and in increasing the frequency of EMG (P<0.05) and the expressions of SP and c-kit (P<0.05). No significant changes were found in the levels of frequency and amplitude of EMG, and expressions of SP and c-kit after routine needling in comparison with the model group (P>0.05), except the excretion time of the first black stool grain (P<0.05).Deep needling at ST25 at depth of 4.5 mm and 10 mm，especially at depth of 10 mm，has a significant effect in promoting gut motility to ameliorate constipation in rats with STC, which may be related to its function in up-regulating the expressions of SP and ICC activity.目的：观察针刺“天枢”不同深度对慢传输型便秘(STC)大鼠结肠传导功能及结肠P物质(SP)、Cajal间质细胞(ICC)表达的影响，探讨其作用机制。方法：将Wistar大鼠随机分为对照组、模型组、常规针刺组、深刺一组和深刺二组，每组10只。采用1 mg/mL复方地芬诺酯混悬液(10 mg/kg)灌胃复制STC大鼠模型。常规针刺组、深刺一组和深刺二组予“天枢”电针干预，分别直刺进针3、4.5、10 mm，每次15 min，每日1次，连续15 d。采用活性炭灌胃法检测大鼠首粒黑便排出的时间，多导生理记录仪检测大鼠结肠肌电频率和振幅，免疫组织化学法检测结肠组织中SP和ICC特异性标志蛋白酪氨酸蛋白激酶受体(c-kit)的阳性表达面积。结果：与对照组比较，模型组大鼠首粒黑便排出时间明显延长(P<0.01)，结肠肌电频率明显降低(P<0.01)、振幅明显升高(P<0.01)，结肠组织中SP、c-kit阳性表达面积明显缩小(P<0.01)；与模型组比较，常规针刺组、深刺一组和深刺二组首粒黑便排出时间明显缩短(P<0.01)，深刺一组和深刺二组结肠肌电频率明显升高(P<0.01)、振幅明显降低(P<0.01)，结肠组织中SP、c-kit阳性表达面积明显增加(P<0.05，P<0.01)；与常规针刺组比较，深刺一组和深刺二组首粒黑便排出时间明显缩短(P<0.05，P<0.01)，结肠肌电频率明显升高(P<0.01)、振幅明显降低(P<0.01)，结肠组织中SP、c-kit阳性表达面积明显增加(P<0.05，P<0.01)；与深刺一组比较，深刺二组首粒黑便排出时间缩短(P<0.05)，结肠肌电频率升高(P<0.05)、振幅降低(P<0.05)，结肠组织中SP、c-kit阳性表达面积增加(P<0.05)。结论：不同深度针刺大鼠“天枢”均对STC有治疗作用，可调节肠道功能，改善便秘症状，尤以针刺深度10 mm效果最显著，其作用机制与调节结肠肌电节律、促进结肠SP及ICC细胞的表达有关。.