OBJECTIVETo investigate the dynamic expression of PTEN in fibrogenic liver tissue of rats and its effect on the activation and proliferation of hepatic stellate cells (HSC).

METHODSA rat model of hepatic fibrosis was established by common bile duct ligation (BDL). The expressions of PTEN in the rat liver tissues were detected by immunohistochemical staining, Western blot and real-time PCR assay. The expressions of PTEN in activated HSC in the rat liver tissues were detected by immunofluorescence double labeling confocal laser scanning microscopy. The alpha-SMA in the rat liver tissues was determined by immunohistochemical staining.

RESULTSThe immunohistochemical staining indicated that there was extensive expression of PTEN in the liver tissues of normal rats, it was expressed mainly in the cytoplasm of the HSC. With the aggravation of hepatic fibrosis, the expression of PTEN in the hepatic tissues decreased gradually (P less than 0.01), while the alpha-SMA positive cells in the hepatic tissues increased significantly (P less than 0.01). The expressions of PTEN protein and mRNA in the rat liver tissues at week 1, 2, 3 and 4 after BDL were all lower than those in the sham operation group (P less than 0.01), and the expressions gradually decreased with the development of hepatic fibrosis (P less than 0.01). Immunofluorescence double labeling confocal laser scanning microscopy showed that PTEN were expressed extensively in activated HSC, especially in the cytoplasm, and with the development of hepatic fibrosis, the PTEN-expressing activated HSC accounted for an increasingly smaller percentage of total activated HSC.

CONCLUSIONThe expressions of PTEN mRNA and protein in rat fibrogenic liver tissues were downregulated, and their expressions in HSC in vivo also decreased. The dynamic expressions of PTEN in liver tissues had a significant negative correlation with the activation and proliferation of HSC.