Wei Chang An pill regulates gastrointestinal motility in a bidirectional manner

Wei Chang An (WCA) is a commercial prescription developed for the coordination of gastrointestinal movement.

To investigate the role of WCA in the regulation of diarrhoea and constipation in rats.

The diarrhoea and constipation models were prepared by gavage of Folium senna and diphenoxylate hydrochloride. Rats were randomized equally (n = 6) into the normal group given saline daily, the positive group given Pinaverium Bromide (13.5 mg/kg) or Sennoside A (0.1 mg/kg) and three WCA-treated groups (22, 44, and 88 mg/kg) by gavage daily for 7 consecutive days. The effects of WCA were assessed by a series of faecal symptoms and histopathology. Gastrointestinal parameters were determined by ELISA. The effect of WCA on gastrointestinal tissues was evaluated by strip assay. Expression of ROCK-1 and MLCK was measured by RT-PCR and Western blotting.

Data from Bristol stool form scale, diarrhoea index, visceral sensitivity, defaecation time, and intestinal propulsive rate showed that WCA protected rats against diarrhoea and constipation (p < 0.01). The up-regulation of Substance P and 5-hydroxytryptamine in diarrhoea rats and down-regulation of Substance P and vasoactive intestinal polypeptide in constipation rats were inhibited by WCA (p < 0.05). WCA stimulated the gastrointestinal strip contractions but inhibited ACh-induced contractions (p < 0.01). The decreased ROCK-1 and MLCK expression in diarrhoea rats and increased in constipation rats were suppressed by WCA (p < 0.01).

WCA has both antidiarrhea and anti-constipation effects, suggesting its bidirectional role in gastrointestinal modulation, and providing evidence of WCA for irritable bowel syndrome treatment.