Effects of Angiotensin(1-7) on Cell Proliferation and Collagen Synthesis of Cardiac Fibroblasts Induced by Angiotensin II

Aim To investigate the effect of Angiotensin(1-7) (Ang(1-7) on cell proliferation and collagen synthesis of cardiac fibroblasts(CF) induced by Angiotensin Ⅱ (Ang Ⅱ). Methods CF were isolated and cultured from Neonatal SD rats. Cell number and cell cycle were evaluated by MTT assay and flowcytometry technique. Type and Ⅲ collagen mRNA expressions in CF were analyzed by RT-PCR. Results ①1 μmol/L Ang Ⅱ significantly increased absorption value of CF(0.24±0.01)compared with control group (0.14±0.01, P0.01), 0.001～1.0 μmol/L Ang(1-7) attenuated the absorption value of Ang Ⅱ group in a concentration dependent manner (0.22±0.01, 0.21±0.01, 0.18±0.01 and 0.16±0.01, P0.01). ②Compared to the control (5.4%±0.7%, 10.8±2.4), cells in S stage (14.0%±0.9%) and proliferatiion index (23.4±1.8), they were markedly increased in 1 μmol/L Ang Ⅱ group (P0.01). In the presence of 0.1 μmol/L Ang(1-7), cells in S stage (8.5%±0.7%) and the proliferatiion index (16.2±2.0) were significantly lower than that of Ang Ⅱ group (P0.01). ③mRNA expressions of typeⅠand Ⅲ collagen in Ang Ⅱ group were significantly higher than those of the control (P0.01), and in the presence of 0.1 μmol/L Ang(1-7), mRNA expressions were reduced in a concentration dependent manner (P0.05). Conclusion The results indicate that Ang(1-7) could inhibi the proliferation of CF and the synthesis of type Ⅰand Ⅲ collagen.