Expression of caveolin-1 and extracellular matrix induced by transforming growth factor beta1 in human fetal lung fibroblasts]

To investigate the expressions of caveolin-1, collagen-I and alpha-SMA in human fetal lung fibroblasts induced by transforming growth factor beta(1) (TGF-beta(1)).Human fetal lung fibroblasts (HFLF) were cultured in vitro, and exposed to TGF-beta(1) with different final concentrations (2, 5, 10 microg/L). Cells without TGF-beta(1) exposure served as the control. Caveolin-1 mRNA and protein, collagen-I and alpha-SMA proteins in cell (at least 5 x 10(8)) lysates, were detected at different points after the treatment of TGF-beta(1), by RT-PCR, Western blot and Immunohistochemistry. Each experiment was repeated 3 times. One-way analysis of variance (ANOVA) was used to compare data among groups, and linear regression was established for correlation analysis.TGF-beta(1) reduced caveolin-1 mRNA and protein expressions in a dose- and time-dependent manner, measured by integral optical density. Compared with the control group (1.22 +/- 0.12 and 1.45 +/- 0.06), caveolin-1 mRNA and protein expressions (0.59 +/- 0.06 and 0.53 +/- 0.04) were significantly reduced, with statistical significance (F = 29.279 and F = 95.786, P < 0.01), in cells exposed to TGF-beta(1) (5 microg/L) for 12 h. The collagen-I and alpha-SMA protein expressions (1.35 +/- 0.09 and 0.75 +/- 0.06) measured by integral optical density increased after stimulation, peaked at 24 h in 5 microg/L TGF-beta(1) group. At that time point, the collagen-I and alpha-SMA protein expressions were 4.2 and 4.8 times of the control group (0.28 +/- 0.04 and 0.18 +/- 0.04), F = 81.221 and F = 65.477, P < 0.01. Caveolin-1 expression had a negative correlation with collagen-I (r = -0.923, P < 0.05) and alpha-SMA protein expression (r = -0.793, P < 0.05).The reduced caveolin-1, which was negatively correlated with expressions of collagen-I and alpha-SMA proteins in HFLF cells exposed to TGF-beta(1), may be related to the development and progress of pulmonary fibrosis.