Liver samples of patients were screened from the Tissue Bank of the China-Japan Union Hospital of Jilin University. Mice liver fibrosis model was performed using intraperitoneal injection of carbon tetrachloride (CCl4) for 12 weeks. Serum IGF-1 levels were detected by enzyme-linked immunosorbent assays (ELISA). Microscopical examination of liver parenchyma was performed using conventional H&E and Masson's staining. Moreover, we investigated the IGF-1 receptor (IGF-1R) signaling pathway at different period after CCl4 administration.
Serum IGF-1 levels were significantly decreased in patients with liver cirrhosis, which is concomitant with the declined circulating levels of IGF-1 in 8 to 12 weeks CCl4-treated mice. Furthermore, the expression of IGF-1R was significantly higher at 12 w compared with control group. In addition, activation of the GSK-3β and FOXO3a were activated during the process of murine chronic liver injury.
The present study demonstrates that decreased circulating IGF-1 levels are involved in human and murine chronic liver disease. Interestingly, overexpression of the IGF-1R, and activation of GSK3β and FOXO3a might be the molecular mechanisms underlying the development of liver cirrhosis.