Hypoxia promotes the collagen synthesis in cultured cardiac fibroblasts of adult rat

Objective To observe the effects of hypoxia on collagen protein and total protein synthesis and the expression of collagen type Ⅰ and Ⅲ mRNA in cultured cardiac fibroblasts of male adult rat. Methods Cardiac fibroblasts (CFs) were isolated from adult Wistar rat ventricle and cultured in vitro either in normoxic or hypoxic condition. The changes of collagen protein and total protein synthesis were determined by measuring the collagenase sensitive ~3Hproline incorporation and the ~3Hleucine incorporation respectively. The changes of expression of proα1(Ⅰ) collagen and proα1(Ⅲ) mRNA were measured by RTPCR. Results The collagenase sensitive ~3Hproline incorporation of CFs was increased by 132%(P0.05)and 163%(P0.01) after 24hour and 48hour exposure to hypoxia (2% O_(2)) respectively. The level of proα1(Ⅰ) collagen mRNA and proα1(Ⅲ) mRNA was significantly elevated in the cells exposed to hypoxia for 12 h, 24 h, 48 h. Conclusion Hypoxia alone can upregulate collagen synthesis in cardiac fibroblasts of adult rat, which may be one of the important mechanisms that hypoxic myocardial fibrosis occurs.