Inhibition of high-mobility group box 1 expression by siRNA in rat hepatic stellate cells

Figure 1 High-mobility group box 1 protein was upregulated after dimethylnitrosamine injection. A: Immunohistochemical study of high-mobility group box 1 (HMGB1) distribution and expression in liver fibrosis specimens (original magnification, × 400). Brown color displays the positive expression. a: There was no immunoreactivity in the normal liver tissue; b: Weak staining in liver fibrosis tissue at 1 wk after the first dimethylnitrosamine (DMN) injection; c: Moderate staining in liver fibrosis tissue at 2 wk after the first DMN injection; d: Strong staining in liver fibrosis tissue at 3 wk after the first DMN injection; B: Immunohistochemical study of collagen type Iin liver fibrosis specimens (original magnification, × 400). Brown color displays the positive expression. Collagen type I was markedly increased during liver fibrogenesis; C: Immunohistochemical study of collagen type III in liver fibrosis specimens (original magnification, × 400). Brown color displays the positive expression. Collagen type III was markedly increased during liver fibrogenesis; D: The amount of HMGB1, collagen types I and III staining in liver tissue was measured using an image analyzer during liver fibrosis. HMGB1 was markedly increased during liver fibrogenesis, correlated with the expression of collagen types I and III (r = 0.90, P < 0.05 and r = 0.89, P < 0.05).