Hepatic injury in rats with obstructive jaundice: roles of the protein kinase C signal pathway and cytoprotection of fructose.

Background: Fructose is cytoprotective during bile salt-induced apoptosis of hepatocytes by regulating protein kinase C (PKC). This study was undertaken to explore the regulating mechanism of hepatic injury in rats with obstructive jaundice, and to detect the PKC signal pathway.

Methods: Rat hepatocytes were isolated by in situ collagenase perfusion and primary culture, and pretreated with various concentrations of PKC agonist phorbol myristate acetale (PMA) and inhibitor chelerythrine for 20 minutes. After pretreatment, 50 mumol/L glycochenodeoxycholate (GCDC) was added for additional 24 hours. Subsequently, the cells were detected by FCM and TUNEL. After adding with different concentrations of fructose and 100 mumol GCDC, the hepatocytes were evaluated by FCM and TUNEL. Experimental obstructive jaundice was induced with fructose and without fructose via double ligation of the bile duct for 3, 7, 14, and 21 days. Apoptotic status in the liver of all rats was detected with TUNEL, and PKC protein in the liver of obstructive jaundice (OJ) with the immunohistochemistry method.

Results: PMA increased GCDC-induced apoptosis and chelerythrine decreased GCDC-induced apoptosis in a concentration-dependent manner. Adding with different concentration of fructose and 100 mumol GCDC, the decreased apoptotic rate was related to the concentration of fructose. The apoptotic rate of the liver was related to times of OJ. PKC and apoptosis index (AI) were the highest after a 14-day ligation of the bile duct without use of fructose. AI and PKC were decreasing from a 14-day ligation of the bile duct with fructose.

Conclusions: PKC takes part in the regulation, occurrence, and progression of hepatic injury in OJ. Fructose is cytoprotective during bile salt-induced apoptosis of hepatocytes by regulating PKC.