BACKGROUNDTo establish an immune complex induced rat liver fibrosis model by intraperitoneal injection of human serum albumin (HSA).

METHODSMale Wistar rats, weighting 110-120 g, were sensitized with HSA by subcutaneous injections at different sites for 4 shots at intervals of 14, 10 and 10 days. Ten days after the fourth injection, the peritoneal booster dose of HSA was administrated to rats twice weekly for 8 weeks with an initial dose of 5 mg, and progressive increase to 20 mg. Liver biopsy was performed at the beginning of HSA booster, 15, 30, 60 days after HSA booster, and 30, 60, 90, 120 days after discontinuation of HSA booster, respectively. Liver samples were examined for histological changes and liver hydroxyproline (HyP) was measured by biochemical method. Fibrosis serum markers hyaluronate acid (HA) and laminin (LN) were determined by RIA method.

RESULTSAfter intraperitoneal administration of HSA, the degree of liver pathological changes, the liver Hyp content and serum HA and LN increased (P<0.05). The longer the HSA administrated, the higher the liver pathological change degree (P<0.05) and the levels of liver Hyp and serum HA (P<0.01). After discontinuation of HSA, the levels of serum HA and liver Hyp decreased significantly (P<0.01) but were still significantly higher than those in the controls (P<0.01). The liver fibrosis formation rate was 100% and the fibrosis lasted more than 120 days.

CONCLUSIONIntraperitoneal administration of HSA to make rat immune complex induced liver fibrosis model is convenient with high liver fibrosis formation rate and long fibrosis lasting time. The model may be used to evaluate the therapeutic effect of antifibrotic drugs.