Intervention Effect of Simo Decoction on Rats with Constipation-predominant Irritable Bowel Syndrome

Objective To investigate the intervention effect and the possible therapeutic mechanism of Simo Decoction( SD) for constipation-predominant irritable bowel syndrome( IBS-C). Methods SD rats were randomly divided into 6 groups, normal group, model group, western medicine control group( treated with Trimebutine 0.1 g·kg-1·d-1), and low-, middle- and high-dose SD groups(in the dosage of 3.6, 1.8, 0.9 g· kg-1·d-1, respectively). IBS-C model was established by tail-clamping method combined with rectal stimulation method. The content of corticotropin-releasing hormone(CRH) in the hypothalamus and brainstem, substance P(SP) in lumbar spinal cord, C-fos mRNA expression in activated distal colonic mucosal mast cells of all the groups were observed. Results On week 2 after treatment with SD, visceral hypersensitivity in low-, middleand high-dose SD groups was significantly decreased( P 0.05 compared with that in the model group). Compared with the normal group, CRH content was increased( P 0.05), SP content and the count of distal colonic mucosal mast cells with positive c-fos mRNA expression were significantly decreased(P 0.05) in the model group. Compared with the model group, CRH content was decreased(P0.05), and SP content and the count of distal colonic mucosal mast cells with positive c-fos mRNA expression were significantly increased(P 0.05) in the four medication groups. Conclusion Th e therapeutic mechanism of Simo Decoction for IBS-C is probably related with the decrease of CRH content in the hypothalamus and brainstem, and with the increase of spinal SP content and c-fos mRNA expression.