Zuojin Pill ameliorates inflammation in indomethacin-induced gastric injury via inhibition of MAPK pathway

Zuojin Pill (ZJP) has been a classic prescription for the treatment of gastrointestinal diseases in China since ancient times. But its effect on non-steroidal anti-inflammatory drugs (NSAIDs) induced gastric injury (GI) is still uncharted. This study aims to investigate the therapeutic effect and molecular mechanism of ZJP on indomethacin (IDO) induced gastric injury. GI was induced in rat by oral administration of 5 mg/kg IDO. Then the rats were treated with ZJP (1.26, 2.52, 5.04 g/kg, ig). The changes of food intake, body weight, gastric pH and general state observation were carried out to determine the improvement of ZJP in IDO-induced GI: HE staining and AB-PAS staining was analyzed to characterize the thickness of gastric mucosa and micro mucosal injury; in order to elucidate the effect of ZJP on IDO-induced inflammatory injury, the inflammatory infiltration of gastric tissue was observed by MPO immunohistochemical method, and the contents of TNF-α, IL-6 and IL-10 were measured. Furthermore, the regulatory mechanism of ZJP in treating IDO-induced GI was predicted with the help of network pharmacology, and the expression levels of key proteins ERK, p-ERK, P38, p-P38, JNK, p-JNK were determined to elucidate the molecular mechanism of ZJP. Current data strongly demonstrated that ZJP alleviated food intake reduction, weight loss and gastric injury caused by IDO and made gastric pH and mucosal thickness return to normal. In addition, ZJP could reduce the level of MPO to alleviate the inflammatory infiltration of gastric tissue. Simultaneously, ZJP could down regulate the expression of TNF-α and IL-6 and up regulate the expression of IL-10 to reduce the damage caused by inflammatory, and create a healing environment. Furthermore, ZJP could significantly inhibit the phosphorylation of ERK, p38 and JNK, which leaded to the increase of inflammatory factors and the damage of gastric mucosa. ZJP improved local inflammation by inhibiting MAPK signaling pathway, and had a good therapeutic effect on IDO-induced GI. This study has reference significance for the study of ZJP in the prevention and treatment of NSAID induced gastric injury. In addition, ZJP may be a new treatment option for the prevention and treatment of NSAID induced gastric disease.