| Background and Objectives:Hepatic fibrosis(HF) caused by various liver diseases is characterized by accumulation of extracellular matrix(ECM),mainly consisting of collagens.HF is an indispensable way of many chronic liver diseases leading to cirrhosis,and some cases may eventually develop to hepatoma.Recent researches showed that HF is a dynamic process,and also the only pathological stage that is reversible in the development of liver cirrhosis.HF can be lessen or recovered completely by an ideal therapy.Unfortunately,up to now,a recognized effectively anti-hepatic fibrosis drug has not been clinically available.Therefore,researches on prevention and therapeutic methods for hepatic fibrosis remain one of the hot and difficult topics.Pirfenidone(PFD) is a micromolecule compound,which was firstly synthesized in 1970s.Initial studies found that PFD had anti-inflammatory actions.Recently,more and more data have validated that PFD has significant therapeutic effects on anti-fibrosis,especially,for pulmonary fibrosis.The clinical therapeutic effects are superior to other commonly used medicine,and little side effects are recorded.The anti-fibrosis mechanism of PFD is still on research,but some studies reported that PFD is a cytokine inhibitor,which can inhibit the biologic activity of fibroblastic cells by regulating some cytokines to suppress cells proliferation and matrix synthesis.The main targets for PFD consist of transforming growth factor-β1(TGF-β1), platelet-derived growth factor(PDGF),tumor necrosis factor-a(TNF-α),connective tissue growth factor(CTGF) and other inflammatory factors.An American obtained the patent of PFD for anti-fibrosis in 1994.The invention of PFD might start a new era of prevention and treament for fibrous degeneration,and PFD had a very good prospect for development.However,there is rarely report on PFD for anti-hepatic fibrosis.This study was designed to investigate PFD effects on hepatic fibrosis in experimental rats induced by dimethylnitrosamine(DMN).Methods:Forty-five male Wistar rats were randomized into three groups i.e.normal group,model group and interventional group.The model group and the interventional group were both intraperitoneally injected with 1%DMN 10 mg/kg per day on the first three days of each week for 4 weeks.The interventional group was given orally PFD 500 mg/kg daily for 4 weeks starting on the day of the first injection of DMN. The normal group was given normal saline instead.At the end of the 4th week,all rats were anaesthetized and weighed,blood samples were obtained immediately from the heart before rats were killed,and then livers and spleens were excised;liver histological observation was performed after hematoxylin and eosin stain(HE)staining and Masson trichrome stain;the ultramicrostructure of hepatic cell,hepatic stellate cell(HSC),sinusoidal endothelial cell(SEC) were observed with transmission electron microscope(TEM);serum hyaluronic acid(HA),laminin(LN),typeⅢprocollagen(PCⅢ),typeⅣcollagen(Ⅳ-C)and TGF-β1 were detected with enzyme linked immunosorbent assay(ELISA);and liver function indicators such as alanine aminotransferase(ALT),aspartate aminotransferase(AST),serum total bilirubin (TBIL) and serum albumin(ALB) were examined by full-automatic biochemistry instrument.Results:1.Compared with the normal group,the model group's bodyweight decreased significantly(P＜0.05);and indices of liver and spleen were higher(P＜0.05); there were no difference between the interventional group and normal group (P＞0.05).Compared with the model group,the interventional group had higher bodyweight(P＜0.05) and splenohepatomegalia was less(P＜0.05).2.Histological examination:HE and Masson stain showed that the hepatic lobules of rats in normal groups exhibited normal structure,no degeneration and necrosis was observed in hepatic cells.The hepatic lobules of rats in model group were destroyed significantly,fibrous connective tissue hyperplasyed obviously extending into the hepatic lobules and pseudo-lobule emerged,inflammatory infiltrated obviously in portal tract.For interventional group,slight disorder was observed in hepatic lobule structure,no typical pseudo-lobule was found,little inflammatory infiltration was noticed in portal tract.The grade of liver inflammation and stage of hepatic fibrosis in interventional group is better than that in model group significantly(P＜0.05).3.Transmission electron microscope demonstrated that hepatic cell damage in interventional group lessened significantly compared with that in model group. The structure of cytoplasmic organoids was still intact,and similar to normal group,and slight collagen fiber was observed in sinus hepaticus and Disse space.4.The serum levels of HA,LN,PCⅢandⅣ-C in interventional group (145.3±14.12ng/mL,97.8±7.22ng/mL,38.1±4.37ng/mL and 52.8±4.62ng/mL respectively) were slightly higher than in normal group(P＜0.05),but significantly lower than that of model group(178.9±20.46ng/mL, 124.1±19.82ng/mL,40.4±3.23ng/mL and 82.5±10.56ng/mL respectively) (P＜0.05,P＜0.05,P＞0.05,P＜0.05).5.Compared with the model group,the interventional group had lower ALT,AST and TBIL levels(P＜0.001),and higher ALB levels(P＜0.001),and there is no difference of ALB between the interventional group and the normal group.6.The content of serum TGF-β1 in the interventional group was significantly lower than that in model group(P＜0.001).Conclusions:1.PFD is able to decrease the levels of serum HA,LN andⅣ-C,and improve stage of hepatic fibrosis;2.PFD is able to decrease transaminase and bilirubin,lessen the grade of liver inflammation,and improve liver function;3.PFD has a determinate protection to parenchymal liver cells,which may induce liver parenchyma reconstitution;4.PFD has significant anti-fibrosis effects by inhibiting synthesis of ECM and secretion of HA in experimental rats,which was presumably caused by inhibition to the production of TGF-β1.5.The model of HF induced by DMN is suitable for studies on efficacy of anti-hepatic-fibrosis agent. |
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