The Effect and Mechanism of Sancao Lichang Decoction on Diarrhea- Predominant Irritable Bowel Syndrome by Regulating Tlr4/Myd88/Nf-Κb Pathway

Objective: To evaluate the effect of Sancao Lichang decoction as traditional Chinese medicine on diarrhea-predominant irritable bowel syndrome (IBS-D) and TLR4/MyD88/NF-κB pathway. Background: Traditional Chinese medicine has made significant progress in preventing and treating irritable bowel syndrome, and its efficacy has been validated by clinical practice. Sancao Lichang decoction is an empirical prescription developed by professor Tang Decai that has been used for many years to treat chronic diarrhoea with good curative effec. Still, its mechanism of action on IBS-D is unknown. Methods: The study sample of Fifty SD rats was randomly divided into a blank group, model group, low-dose group, medium-dose group, and high-dose group (n = 10). The IBS-D rat models were established by restraining stress method and acetic acid enema. After different treatments, defecation frequency, fecal water content (FWC), serum IL-6 and TNF-α contents, and protein level of TLR4/MyD88/NF-κB in colon tissues were detected separately. Results: The indexes of rats in each group were significantly different. The increase in body weight in the medium-dose and high-dose groups was significantly higher than that in the model group (p < 0.05). Compared with the model group, the medium and high dose groups had lower diarrhea frequency, FWC, interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-α) (p < 0.05). The expression levels of TLR4, MyD88, and NF-κB protein in the colon of the three groups treated with Sancao-Lichan decoction were significantly lower than those in the model group (p < 0.01). After different treatments, the colonic mucosa of rats in each group was stained with HE, which proved that the structural damage of colonic mucosa was improved after treatment with Sancao Lichang decoction, and the improvement effect was dose-dependent. Conclusion: Sancao Lichang decoction may reduce IBS-D by inhibiting TLR4/MyD88/NF-κB pathway, inhibiting the inflammatory response, and improving intestinal mucosal barrier function.