Effects of Nrf2 overexpression on proliferation,activation and collagen type I synthesis in cultured hepatic stellate cells stimulated by ethanol

AIM：To investigate the effects of nuclear factor E2-related factor 2 (Nrf2) overexpression on the proliferation, cell cycle distribution, collagen type I (Col I) synthesis and alpha-smooth muscle actin (α-SMA) expression in cultured hepatic stellate cell line HSC-T6 stimulated by ethanol. METHODS：Cultured HSC-T6 cells were transfected with pEGFP-Nrf2 or pEGFP-N1 (empty vector) plasmid by liposome transient transfection. The cells were divided into control group, ethanol group, ethanol+pEGFP-Nrf2 group and ethanol+pEGFP-N1 group. The mRNA expression of Nrf2, α-SMA and Col I was determined by RT-PCR, and their protein expression was detected by Western blotting. Cell proliferation was assessed by MTT assay, and cell cycle was detected by flow cytometry. RESULTS：The pEGFP-Nrf2 plasmid was successfully transfected into HSC-T6 cells, and the mRNA and protein expression of Nrf2 was higher than other three groups 48 h after transfection (P<0.05). Compared with control group, the cell proliferation and the mRNA and protein expression of α-SMA and Col I in ethanol group and ethanol+pEGFP-N1 group were significantly increased (P<0.05), and the numbers of HSC-T6 cells were decreased in G1 phase and increased in S phase (P<0.05), without significant differences between the two groups (P>0.05). Meanwhile, the cells in ethanol+pEGFP-Nrf2 group showed significantly decreased proliferation level, down-regulated mRNA and protein expression of α-SMA and Col I, higher numbers in G1 phase and lower numbers in S phase compared with ethanol group and ethanol+pEGFP-N1 group (P<0.05). CONCLUSION：Nrf2 overexpression could significantly down-regulate the expression of α-SMA and Col I and cause G1/S phase arrest in HSC-T6 cells cultured with ethanol, thus inhibiting the proliferation and activation of the cells.