Purified hepatitis B virus induces human Mesangial cell proliferation and extracellular matrix expression In Vitro

BACKGROUND: Hepatitis B virus (HBV) induces proliferation of human mesangial cells (HMCs), and extracellular matrix expression through the deposition of immune complexes in renal tissue. However, it is unclear whether HBV can directly affect HMCs. In this study, the effects of purified HBV on HMC proliferation and extracellular matrix expression in vitro was determined. FINDINGS: HBV was purified using sucrose density gradient centrifugation. HMCs were co-cultured with purified HBV (10(4)–10(6) copies/ml) for 48 h, and cell proliferation determined using 5-ethynyl-2′-deoxyuridine immunofluorescence assays. After HMCs were co-cultured with 10(6) copies/ml purified HBV for 0, 12, 24, 36 and 48 h, expression of type IV collagen and fibronectin was measured using enzyme-linked immunosorbent assays. Three titers of purified HBV (10(4), 10(5), and 10(6) copies/ml) induced HMC proliferation, with the proportion of increases in cell numbers at 24.7 ± 4.3, 31.2 ± 9.4, and 36.8 ± 7.5%, respectively. All these increases were significantly higher than those for the control group (13.6 ± 4.2%) (All p < 0.05). Purified HBV (10(6) copies/ml) significantly increased the levels of type IV collagen and fibronectin in supernatants compared with the control group at 12 and 48 h (All p < 0.05). CONCLUSIONS: Purified HBV can directly promote HMC proliferation and expression of type IV collagen and fibronectin, and could be involved in the pathogenesis of HBV-associated glomerulonephritis.