Endostar,a novel human recombinant endostatin,attenuates liver fibrosis in CCl 4 -induced mice

Abstract

Decreasing hepatic fibrosis remains one of the major therapeutic challenges in hepatology. The present study aims to evaluate the effect of Endostar on both CCl₄-induced liver fibrosis in mice and a hepatic stellate cell (HSC) line. Two main models were studied: (i) a liver fibrosis model was induced in BALB/c mice using CCl₄ by intraperitoneal injection for six weeks. Six animal groups were studied: group 1: normal animals; group 2: CCl₄-induced liver fibrosis; group 3: CCl₄ + Endostar 20 mg/kg/d, six weeks; group 4: CCl₄ + Endostar 10 mg/kg/d, six weeks; group 5: CCl₄ + Endostar 20 mg/kg/d, four weeks; group 6: CCl₄ + Endostar 10 mg/kg/d, four weeks corresponded to different Endostar doses and duration of administration. Liver fibrosis was evaluated by histopathological staining and liver hydroxyproline content. Expressions of collagen type I, α-smooth muscle actin (α-SMA), TGF-β1 and VEGFR were measured by real-time polymerase chain reaction (PCR). (ii) A liver cell model. HSC-T6 cells were cultured with or without Endostar for 12 h or 24 h. Expressions of collagen type I, α-SMA, and TGF-β1 were measured by real-time PCR. Collagen I and transforming growth factor β1 (TGF-β1) contents in cell supernatant were measured by enzyme-linked immunosorbent assay. As compared to the group without Endostar, liver fibrosis scores and hydroxyproline content were decreased in both Endostar groups (P < 0.05). Moreover, Endostar inhibited the hepatic expression of α-SMA, TGF-β1, Collagen-1, VEGFR1, and VEGFR2 mRNA (P < 0.05). In the HSC-T6 cell line model, Endostar profoundly inhibited the expression of α-SMA, Collagen-1, and TGF-β1 mRNA. Expressions of Collagen-1 and TGF-β1 protein were decreased in the Endostar group as compared to the normal controls in the supernatant of HSC-T6 cells (P < 0.05). Endostar decreased both liver fibrosis in CCl₄-induced mice and collagen synthesis in HSCs in vitro. Therefore, this recombinant human endostatin is a promising compound for counteracting liver fibrosis.