Hepatitis B virus directly promotes collagen I expression of LX‐2 cells without infection in vitro

Abstract

To investigate direct effects of hepatitis B virus (HBV) on collagen type I in vitro. Collagen type I were measured after LX-2 cell cultured with purified or serum HBV for 12, 24 and 48 h. Furthermore, evidence of HBV infection to LX-2 were detected, and different inhibitors were used to identify pathways regulating collagen I expression. The 3 × 10(5) IU/mL purified/serum HBV increased collagen type I mRNA expression by 2.2-/3.2- and 1.3-/1.5-fold at 24 and 48 h, respectively. Collagen type I protein in the supernatant of purified/serum HBV group also increased compared to the control group (408.0 ± 8.0/384.4 ± 6.8 vs 262.7 ± 15.7 ng/mL, P < 0.05). However, the 3 × 10(7) IU/mL purified/serum HBV increased collagen type I expression similar to that of 3 × 10(5) IU/mL, while 3 × 10(3) IU/mL group showed no effect. Human HBV immunoglobulin alleviated HBV-induced collagen I expression, but no evidence of HBV infection was found. Neutralization of transforming growth factor beta, tumor necrosis factor alpha, platelet-derived growth factor, extracellular signal-regulated kinase and TGF-β receptor had no obvious inhibitory effects; only inhibition of p38 mitogen-activated protein kinase decreased collagen type I mRNA expression by 0.5-/0.4- and 0.4-/0.3-fold at 24 and 48 h, respectively. It reduced collagen type I protein in the purified/serum HBV group for 48 h (252.1 ± 14.1/251.7 ± 18.8 vs 403.9 ± 4.9/385.0 ± 4.2 ng/mL, P < 0.05). HBV directly promotes collagen type I expression of LX-2 cells without infection in vitro.