Effect of TGF-β1 on the expression of collagen in rat atrial and ventricular fibroblasts / 解放军医学杂志

ABSTRACT

Objective To observe the effect of transforming growth factor beta 1 (TGF-β1) on the expression of collagen in rat atrial and ventricular fibroblasts, and to investigate its specific molecular mechanisms. Methods Tissue explant attachment was used to culture fibroblasts obtained from the atrium and ventricle of rat heart, and they were identified with SABC immunocytochemical staining, and then the following experiments were carried out. (1) Hydroxyproline digestion was performed to study the effects of TGF-β1, within different concentrations (0, 5, 10ng/ml) and different action time (6, 12, 24, 48h) on the content of hydroxyproline in rat's atrial and ventricular fibroblasts. (2) Rat's atrial and ventricular fibroblasts were stimulated with TGF-β1 in optimal concentration and action time, the expression of α-smooth muscle actin (α-SMA) was determined with Western blotting, and the expressions of typeand III collagen mRNA were evaluated with reverse-transcription PCR. The contents of hydroxyproline in the respective cells were measured with hydroxyproline determination. Western blotting was used to measure the protein expression of Smad2/3, p-Smad2/3 and Smad7. Results (1) TGF-β1 was shown to stimulate the collagen synthesis in rat's atrial and ventricular fibroblasts, and the optimal stimulus was TGF-β1 concentration 5ng/ml with action time of 24h. (2) After being stimulated by optimal stimulation effect of TGF-β1, the expression of typeand III collagen and p-Smad2/3 increased, while that of Smad7 decreased significantly only in atrial fibroblasts (P1 under optimal stimulating conditions. Conclusion TGF-β1 can induce dysbolism of collagen of cardiac fibroblasts with abnormal expression of cytoskeletal protein, which may occur more obviously in rat's atrial fibroblasts than in ventricular fibroblasts, and its mechanism may be related with TGF-β1/SMAD pathway.