[Effects of electroacupuncture at "Zhongliao" and "Xialiao" on serotonin signaling system and short-chain fatty acids in slow transit constipation rats].

To observe the effect of electroacupuncture (EA) at "Zhongliao" (BL33) and "Xialiao" (BL34) on the 5-hydroxytryptamine (5-HT) signaling system in colon tissue and short-chain fatty acids in feces of rats with slow transit constipation (STC), so as to explore the underlying mechanisms of EA in the treatment of STC.A total of 32 SD rats were randomly divided into normal, model, drug control and EA groups, with 8 rats in each group. The STC model was established by intragastric administration of loperamide for 14 days. The EA stimulation (2 Hz/15 Hz) was performed at bilateral BL33 and BL34 for 30 min, once a day for 14 days. The first black stool de-fecation time and fecal water content were detected after treatment. The expressions of 5-hydroxytryptamine 4 receptor (5-HT4R), tryptophan hydroxylase 1 (TPH1) and 5-HT transporter (SERT) in colon tissues were detected by Western blot. The contents of substance P (SP) and vasoactive intestinal peptide (VIP) in serum were detected by ELISA. The contents of 5-HT in colon tissue and short chain fatty acid (SCFA) in feces were detected by mass spectrometry.Compared with the normal group, the fecal water content, the expressions of 5-HT, 5-HT4R, TPH1 and SERT in colon tissue, the content of serum SP were significantly decreased (P<0.05), the first black stool de-fecation time, and the content of serum VIP was significantly increased (P<0.05), the contents of SCFA in feces were significantly decreased except isobutyric acid (P<0.05) in the model group. Compared with the model group, the fecal water content, the expressions of 5-HT, 5-HT4R, TPH1 and SERT in colon tissues, the contents of acetic acid and butyrate in feces were significantly increased (P<0.05) in the EA and drug control groups, the first black stool defecation time was decreased (P<0.05) in the EA and drug control groups, and the content of serum SP was increased and the content of serum VIP was decreased (P<0.05) in the EA group. Compared with the drug control group, the content of serum VIP was significantly decreased (P<0.05), and the expressions of TPH1 and SERT in colon tissue were significantly increased (P<0.05) in the EA group.EA at BL33 and BL34 can promote intestinal motility by intervening multiple links of 5-HT signaling system in treating STC.目的：观察电针“中髎”“下髎”对慢传输型便秘(STC)大鼠结肠5-羟色胺(5-HT)信号系统及粪便中短链脂肪酸(SCFA)的影响，探讨电针治疗STC的作用机制。方法：SD大鼠随机分为正常组、模型组、阳性药组及电针组，每组8只。采用洛哌丁胺灌胃建立STC大鼠模型。阳性药组予6 g/kg乳果糖灌胃治疗，电针组电针“中髎”“下髎”，每次30 min，两组均每日治疗1次，连续干预14 d。观察各组大鼠首粒黑便排出时间及粪便含水率；Western blot法检测各组大鼠结肠组织中5-羟色胺4受体(5-HT4R)、色氨酸羟化酶1(TPH1)、5-HT转运体(SERT)相对表达量；ELISA法检测各组大鼠血清P物质(SP)、血管活性肠肽(VIP)含量；高效液相色谱-质谱联用法检测各组大鼠结肠组织中5-HT含量及粪便中SCFA含量。结果：与正常组比较，模型组大鼠首粒黑便排出时间延长(P<0.05)，粪便含水率降低(P<0.05)；结肠组织中5-HT含量及5-HT4R、TPH1、SERT蛋白表达量降低(P<0.05)；血清SP含量降低(P<0.05)，VIP含量升高(P<0.05)；粪便SCFA含量（除异丁酸外）均显著降低(P<0.05)。与模型组比较，电针组和阳性药组大鼠首粒黑便排出时间缩短(P<0.05)，粪便含水量升高(P<0.05)；结肠组织中5-HT含量及5-HT4R、TPH1、SERT蛋白表达量升高(P<0.05)；粪便中乙酸及丁酸含量均明显升高(P<0.05)；电针组血清SP含量升高(P<0.05)，VIP含量降低(P<0.05)。电针组大鼠血清VIP含量较阳性药组显著降低(P<0.05)；结肠组织TPH1、SERT蛋白表达量较阳性药组显著升高(P<0.05)。结论：电针“中髎”“下髎”可以通过干预5-HT信号系统的多个环节促进肠道动力，从而缓解STC。.