Role of PPARγ in Ulcerative Colitis and Traditional Chinese Medicine Intervention： A Review / 中国实验方剂学杂志

ABSTRACT

Ulcerative colitis （UC） is a chronic inflammatory bowel disease primarily affecting the colon and rectum， with the typical symptoms such as abdominal pain， bloody diarrhea， and tenesmus. The pathogenesis of UC remains to be fully elucidated. The disease is prone to recurrence， seriously affecting the patients' quality of life. Conventional therapies for UC have limitations， including unsatisfactory clinical efficacy， lengthy courses， and adverse reactions. Therefore， there is an urgent need to explore new therapeutic agents. Peroxisome proliferator-activated receptor gamma （PPARγ）， a ligand-dependent nuclear receptor protein that plays a crucial role in maintaining intestinal homeostasis， is closely associated with the onset and development of UC. Traditional Chinese medicine （TCM） has advantages such as multi-targeting and mild side effects in the treatment of UC. Recent studies have shown that TCM can exert the therapeutic effects on UC by modulating PPARγ. The TCM methods for regulating PPARγ include clearing heat， drying dampness， moving Qi， activating blood， resolving stasis， invigorating the spleen， warming the kidney， and treating with both tonification and elimination. On one hand， TCM directly activates PPARγ or mediates signaling pathways such as nuclear factor-κB （NF-κB）， mitogen-activated protein kinase （MAPK）， Toll-like receptor 4 （TLR4）， and regulates helper T cell 17 （Th17）/regulatory T cell （Treg） balance to promote macrophage polarization from the pro-inflammatory M1 phenotype to the anti-inflammatory M2 phenotype， thereby inhibiting intestinal inflammation. On the other hand， TCM regulates the intestinal metabolism to activate PPARγ， lower the nitrate level， and maintain local hypoxia. In this way， it can restore the balance between specialized anaerobes and facultative anaerobes， thereby improving the gut microbiota and treating UC. This article summarizes the role of PPARγ in UC and reviews the research progress of TCM in treating UC by intervening in PPARγ in the last five years， aiming to give insights into the treatment and new drug development for UC.