ABSTRACT
OBJECTIVE: To observe the effect of acupoint application at bilateral "Tianshu" (ST25) on intestinal mobility and immunoactivity of vasoactive intestinal peptide (VIP) and substance P (SP) in colonic myenteric plexus of rats with functional constipation (FC), so as to analyze its mechanisms underlying improving FC. METHODS: Forty male SD rats were randomly divided into 4 groups, namely normal control, model, acupoint application and medication, with 10 rats in each group. The FC model was established by gavage of Loperamide Hydrochloride suspension fluid (0.5 mg/mL, 3 mg·kg-1·d-1) for 7 days. Herbal medicine paste (composed of Rheum Officinale, Sodium Sulfate, Mangnolia Officinalis, etc.) was applied to bilateral ST25 for 6 h, once daily for 4 weeks. Rats of the medication group were treated by gavage of Mosapride suspension fluid (0.15 mg/mL, 1.58 mg·kg-1·d-1) for 4 weeks. After the treatment, the rats were deprived of water for 12 hours, and then treated by gavage of 2 mL of activated carbon suspension, followed by recording the first black defecation time and the number of fecal particles and water content of feces within 6 h so as to assess the intestinal mobility. The immunoactivity and average surface density of VIP and SP positive granules in the colonic myenteric plexus were detected by immunohistochemistry. RESULTS: Compared with the normal control group, the first black defecation time was significantly prolonged, and the number and water content of fecal particles within 6 h, and the expression and the average surface density of VIP and SP were significantly reduced in the model group (P0.05). CONCLUSION: Acupoint application may improve the intestinal motility in FC rats, which may be asso-ciated with its effects in up-regulating the immunoactivity of VIP and SP in colonic myenteric plexus of the large intestine.