Effects of insulin-like growth factor binding protein-related protein 1 in mice with hepatic fibrosis induced by thioacetamide

Background Insulin-like growth factor binding protein-related protein 1 (IGFBPrP1) can activate hepatic stellate cells and increase extracellular matrix (ECM) in vitro. However, the effects of IGFBPrP1 in mice with hepatic fibrosis, and the mechanisms of these effects, are currently unknown. We aim to address these issues in this study. Methods Intraperitoneal injection of thioacetamide (TAA) is a classic method for establishing a mouse model of hepatic fibrosis. Using this model, we administered anti-IGFBPrP1 antibody, again via intraperitoneal injection. The morphological changes of liver fibrosis were observed with both HE and Masson stainning. The immunohistochemical assays and Western blotting were used to measure changes in IGFBPrP1, alpha-smooth muscle actin (alpha-SMA) and ECM in liver tissues, and the expression of transforming growth factor-beta 1 (TGF-beta 1) and Smad3. Data were statistically analyzed using one-way analysis of variance (ANOVA), the SNK-q test for inter-group differences. Results The Masson staining analysis showed that compared with normal control group, content of collagen fiber in TAA5w group was significantly increased (P<0.01), and it was significantly decreased in TAA5w/aIGFBPrP1 group compared with in TAA5w group (P <0.01). The expression of hepatic IGFBPrP1, alpha-SMA, TGF-beta 1, Smad3, collagen I and fibronectin (FN) was significantly up-regulated in the TAA5w group (P <0.01). Anti-IGFBPrP1 treatment reversed these changes (P <0.01). Conclusions IGFBPrP1 plays an important role in the development of hepatic fibrosis. Anti-IGFBPrP1 prevents fibrosis in mice by suppressing the activation of hepatic stellate cells, inhibiting the synthesis of major components of the ECM (namely, collagen I and FN). The mechanism for this suppression of fibrosis is associated with the TGF-beta 1/Smad3 signaling pathways. Chin Med J 2010;123(18):2521-2526