The Expressions Of Nuclear Factor Kappa B In The Liver Of Obstructive Jaundice Rats And Interfering Effects Of Verapamil

OBJECTIVETo investigate the role of nuclear factor kappa B(NF-κB) in liver damage in rats with obstructive jaundice and the protective effect of verapamil.METHODS(1) Forty eight male Sprague-Dawley rats were randomly divided into three groups(16 rats each):bile duct-ligation(BDL) group,bile duct-ligation plus verapamil(BDL+V) group and sham-operation(Sham) group.(2)Rats were anesthetized with ketamine by intraperitoneal injection. In rats of BDL group and BDL+V group,common bile duct were ligated and sectioned.In sham group,rats were only exposed the common bile duct.(3) The rats in BDL+V group were daily intraperitoneally injected with verapamil(2 mg/kg/d).In Sham group and BDL group the rats were intraperitoneally injected with normal saline in the same period.(4) The rats were sacrificed at the 7th and 14th day post operation. Besides of hepatic pathological changes in hematoxylin and eosin(HE) stained sections,the following parameters were measured:expressions of hepatic NF-κB p65(by Wesrern Blotting and immunohistochemistry methods),hepatocellular apoptosis index(AI,by TUNEL method), contents of maleicdialdehyde(MDA) and superoxide dismutase(SOD) in hepatic tissue,as well as levels of total bilirubin(TB),alanine aminotransferase(ALT),aspartate aminotransferase(AST),tumor necrosis factor-α(TNF-α) and interleukin-6(IL-6) in serum.RESULTS(1) Pathological changes of the liver by optical microscope in HE staining:Small bile duct hyperplasia,inflammatory cell infiltration, degeneration and necrosis of liver cell in some region can be seen in BDL group and BDL+V group;but at the same time point,liver cell degeneration and necrosis in BDL+V rats were lighter than BDL group. No significant histopathologically hepatic changes observed in Sham group.(2) Expressions of NF-κB p65 in liver tissue:Significantly enhanced expressions of hepatic NF-κB p65 were showed in BDL and BDL+V group;but in BDL+V group,expressions of NF-κB p65 were obviously lower than BDL group(P＜0.01).(3) Apoptosis index(AI) of liver cells in BDL and BDL+V group were significantly higher than Sham group(P＜0.01),but the levels of AI in BDL+V group were obviously lower than BDL group(P＜0.01 to P＜0.05).(4) Contents of MDA and SOD in liver tissue:In BDL and BDL+V group,hepatic MDA were significantly higher than Sham group wheras SOD lower than Sham group.In BDL+V group,lower MDA(P＜0.01 to P＜0.05) and higher SOD(P＜0.05) were found compared with BDL group.(5) Changes in serum TNF-αand IL-6:Levels of serum TNF-αand IL-6 in BDL+V group and BDL group were significantly higher than those in sham group.Compared with BDL group,however,significantly lower levels were found in BDL+V group(P＜0.01 to P＜0.05).CONCLUSIONS(1) Hepatic NF-κB is activated in rats with obstructive jaundice.The activation of NF-κB is associated with the liver injury by upregulating expression of proinflammatory mediators.Target on the activity of NF-κB may be effective to reduce liver injury and other organ dysfunction in obstructive jaundice.(2) Administration of calcium channel blocker verapamil can inhibit expression of hepatic NF-κB,reduce hepatocellular apoptosis,as well as downregulate serum TNF-αand IL-6.(3) The effect of verapamil on expression of NF-κB may through reducing the generation of oxygen free radicals and inhibiting the degradation of IKB,thereby reducing the activation of NF-κB translocation.