Background: Cholelithiasis, known as gallstone, was a common and frequently occurring disease worldwide. Mucus was a viscoelastic protective layer lining the surface of mucosa and synthesized by specialized epithelial cells. Yinchenhao decoction was a classic prescription, first documented in Treatise on Febrile Disease. It had a definite and significant therapeutic effect on cholelithiasis, used as a complement to surgery. Our study aimed to investigate the pathological mechanism of cholelithiasis and the therapeutic mechanism of yinchenhao decoction via mucin from gallbladder-intestine.
Methods: The solubility of cholesterol in fasted state simulated intestinal fluid (FaSSIF) without and with mucin was tested. The experiment of supersaturation stability was designed by solvent-shift method. The animal experiment was performed by cholelithiasis model of high cholesterol diet. The stones were observed and the related lipid was tested by automatic biochemical analyzer. The mucin was detected by PCR and western blot. Statistics was analyzed using χ2-tests and t-tests.
Results: There was no significant difference in the solubility of cholesterol between FaSSIF without and with mucin. Tss or AUC significantly increased with addition of mucin to FaSSIF (p<0.05). A significant difference was observed in stone rate between the normal group and the model group (p<0.05). Stone rate in the model group showed a significant difference from the yinchenhao decoction group (aspirin group) (p<0.05). The level of related lipid showed a significant increase between the normal group and the model group (p<0.05), while there was a significant decrease between the model group and the yinchenhao decoction group (aspirin group) (p<0.05). A significant increase in the MUC5AC or MUC2 expression was observed between the normal group and the model group (p<0.01). The yinchenhao decoction group (aspirin group) caused a significant decrease in the MUC5AC or MUC2 expression, compared with the model group (p<0.01).
Conclusions: In cholelithiasis, the mucin in gallbladder (MUC5AC) highly expressed, shortened cholesterol supersaturation, and promoted cholesterol crystallization; the mucin in small intestine (MUC2) highly expressed, prolonged cholesterol supersaturation, and promoted cholesterol absorption. The yinchenhao decoction inhibited the expression of mucin from gallbladder-intestine for the treatment of cholelithiasis.