The Influence of Angiotensin II Receptor Blockade on the Expressions of ColIand TIMP-1 mRNA in Cardiac Fibroblast of Adult Rat

Objective To investigate the role of angiotensin Ⅱ receptor type 2 (AT2) on collagen metabolism in cardiac fibroblast, and the difference between AT2 and angiotensin Ⅱ receptors type 1(AT1). Methods Adult rat cardiac fibroblasts were isolated and cultured. The cells were divided into 4 groups: Angiotensin Ⅱ (AngⅡ), AngⅡ+Losartan, AngⅡ+PD123319, AngⅡ+Losartan+PD123319. Semi-quantitative reverse transcription PCR was used to determine the mRNA levels of collagenⅠ(ColⅠ) and tissue inhibitor of metalloproteinase 1 (TIMP-1). Results Losartan-treatment making AT1 blockade decreased ColⅠmRNA to 71.8% in cardiac fibroblasts, AT2 blockade from PD123319-treatment decreased ColⅠmRNA to 81.5%, co-treatment of both AT1 and AT2 blockade decreased ColⅠmRNA to 50.9%; the AT1 blockade with Losartan-treatment decreased TIMP-1 mRNA to 88.1% in cardiac fibroblasts, AT2 blockade by PD123319-treatment decreased TIMP-1 mRNA to 75.4%, Both AT1 and AT2 blockade by co-treatment decreased TIMP-1 mRNA to 44.1%. Conclusion AT2 receptor is involved in collagen metabolism in cardiac fibroblast by regulating the levels of ColⅠand TIMP-1 mRNA.