Effect of reduced glutathione on proliferation of rat hepatic stellate cells and the Nrf2/HO-1 signaling pathway

Abstract

To explore the effects of reduced glutathione (GSH) on the proliferation of hepatic stellate cells and the nuclear factor erythroid 2-related factor 2 (Nrf2)/heme oxygenase-1 (HO-1) signaling pathway. The rat HSC-T6 cell line was activated by lipopolysaccharide (LPS; 0.1 mug/ml) and incubated with various concentrations of GSH (0, 1, 2, 5 and 10 mmol/L) for 24 h. Cell proliferation was evaluated by the MTT colorimetric assay. Collagen IV and hyaluronic acid (HA) contents were measured by chemiluminescence immunoassay of cell supernatants. Nrf2 and HO-1 protein expression was observed by immunohistochemistry. Nrf2 and HO-1 mRNA expression was assessed by semi-quantitative reverse transcriptase-polymerase chain reaction (RT-PCR). HO-1 activity was analyzed by spectrophotometer. GSH treatment inhibited HSC-T6 proliferation and decreased the secretion of HA and collagen IV (P less than 0.05); GSH treatment of HSC-T6 cells also led to increased expression of Nrf2 and HO-1, and increased activity of HO-1 (P less than 0.05). GSH can inhibit the proliferation of hepatic stellate cells in vitro and reduce secretion of hyaluronic acid and collagen IV. The underlying mechanism in HSC-T6 cells may involve regulation of the Nrf2/HO-1 signaling pathway.