Objective:To study the protective effect and the possible mechanisms of shenfu injection(SFI) on hepatic injury in rats with severe acute pancreatitis (SAP).Methods:Forty-two male Wistar rats were randomly divided into 3 groups. Sham operation group(SO, n=6) underwent laparotomy only; SAP group,the model was established by retrograde injection of 50% sodium taurocholate into the bili-pancreatic duct in Wistar rats; SAP+SFI group, SAP rats were given SFI 10 ml/kg body wt intraperitoneally 2 h before SAP model established. Rats were sacrificed at 3, 6 and 12 hours after operation. The liver and pancreas tissues were obtained to observe their pathological changes with light microscope. The quantity of ascites was also recorded. The serum levels of alanine aminotransferase (ALT) and amylase were determined at three time points (6 rats for each time point). The expression of tumor necrosis factor alpha(TNF-α) mRNA in the liver was detected by reverse transcription polymerase chain reaction(RT-PCR). The activity of NF-kappaB in liver was examined by immunohistochemical methods.Results:The serum levels of ALT and amylase increased significantly in groups SAP compared with those in group SO at all the three time points(P＜0.01). The expression of TNF-α mRNA in group SAP was increased significantly at 3 to 6 hours, and reached peak at 6 hours, and then decreasd at 12 hours. However, the level of TNF-α mRNA in groups SAP were still significantly higher than that in group SO at all the three time points(P＜0.01 or P＜0.05). The activity of NF-kappaB was higher in groups SAP than that in group SO at the 3 time points (P＜0.01 or P＜0.05). Liver and pancreas pathological damages were severer in groups SAP than in group SO. In SAP+SFI groups, the serum levels of ALT decreased significantly compared to that of groups SAP(P＜0.01 or P＜0.05), and the expression of TNF-α mRNA was also significantly lower than that in groups SAP at all the three time points(P＜0.01 or P＜0.05). The activity of NF-kappaB in groups SAP+SFI was lower than that in groups SAP at the 3 time points (P＜0.01 or P＜0.05). Liver and pancreas pathological damages were milder in groups SAP+SFI than that in groups SAP.Conclusions:These experimental results suggest that NF-kappaB and TNF-α play an important role in the pathogenesis of liver injury in rats with SAP. SFI can reduce pathological damage of SAP and SAP on the liver. Its mechanism might be related to inhibition of activity of NF-kappaB and to decrease in release of inflammatory mediators such as TNF-α.