ABSTRACT
To investigate the molecular mechanism of hydroxycamptothecin (HCPT)-mediated anti-hepatic fibrosis by evaluting its effects on expression of tumor growth factor-beta 1 (TGFb1), alpha-smooth muscle actin (a-SMA) and collagen I (Col I) in hepatic satellite cells (HSCs). Cultured HSCs were treated with different concentrations of HCPT: low-dose group, 0.25 mg/L; middle-dose group, 0.5 mg/L; high-dose group, 0.75 mg/L; and control group, 0 mg/L. Cell proliferation was assessed by the MTT assay. The mRNA expressions of TGFb1, a-SMA and Col I were determined by reverse transcription-polymerase chain reaction. The protein expressions of TGFb1 and a-SMA were detected by Western blot. The content of Col I in the cultured HSCs' supernatant was measured by enzyme-linked immunosorbent assay. The MTT absorbance values of the low-dose group (0.631+/-0.074), middle-dose group (0.469+/- 0.012) and high-dose group (0.204+/- 0.001) were significantly lower than that of the control group (0.793+/-0.098; F = 82.86, P less than 0.01). Compared with the control group, the HCPT-treated groups showed significantly down-regulated gene expressions of TGFb1 (control: 0.716+/-0.064 vs. low: 0.611+/-0.040, middle: 0.510+/-0.014, high: 0.403+/-0.026), a-SMA (control: 0.696+/-0.075 vs. low: 0.579+/-0.037, middle: 0.470+/-0.024, high: 0.299+/-0.017), and Col I (control: 1.019+/-0.056 vs. low: 0.835+/-0.022, middle: 0.696+/-0.055, high: 0.322+/-0.104) (all, P less than 0.01). Meanwhile, HCPT-treated HSCs showed significantly reduced protein expressions of TGFb1 (control: 0.872+/-0.053 vs. low: 0.654+/-0.047, middle: 0.545+/-0.042, high: 0.436+/-0.039) and a-SMA (control: 0.858+/-0.050 vs. low: 0.620+/-0.045, middle: 0.525+/-0.042, high: 0.434+/-0.052) (all, P less than 0.01). The Col I levels secreted by HSCs were significantly lower in the HCPT-treated groups (low: 168.367+/-16.453 ng/ml; middle: 141.284+/-11.731 ng/ml; high: 132.910+/-10.048 ng/ml) than in the control group (188.733 +/-18.299 ng/ml) (all, P less than 0.01). The mechanism of HCPT-mediated anti-hepatic fibrosis may involve down-regulation of TGFb1 expression to inhibit HSC proliferation and activation, as well as reduction of Col I synthesis and secretion.