RESUMO
OBJECTIVE: To investigate the effects and mechanisms of rosuvastatin on angiotensin -converting enzyme 2 (ACE2) in the process of neointimal formation after vascular balloon injury in rats, and to explore the effects of ACE2 and rosuvastatin in restenosis. METHODS: Thirty-six Wistar rats were randomly allocated into three groups: control group (n = 12), surgery group (n = 12), and statin group (n = 12). Aortic endothelial denudation of rats was performed using 2F balloon catheters. At days 14 and 28 after injury, aortic arteries were harvested to examine the following. Intimal thickening was examined by hematoxylin and eosin staining. We measured angiotensin II (Ang II) and angiotensin 1-7 (Ang-[1-7]) levels by a radioimmunological method or enzyme-linked immunosorbent assay. Protein and mRNA expression of ACE2 and Ang II type 1 receptor (AT1) were investigated by immunohistochemistry, Western blots, and Reverse transcriptase-polymerase chain reaction (RT-PCR). We measured changes in proliferating cell nuclear antigen (PCNA) by immunohistochemistry. The level of phosphorylated extracellular signal regulated kinase 1/2 (P-ERK1/2) was evaluated by Western blotting. RESULTS: Proliferation of vascular smooth muscle cells (VSMC) and intimal thickening were higher at day 14 after vascular balloon injury in the surgery group compared with the control group. Proliferation of VSMC was decreased by day 28 after injury, while intimal thickening continued. With rosuvastatin treatment, the extent of VSMC proliferation and intimal thickening was reduced at day 14 and 28 after injury. Ang II and P-ERK levels were significantly increased, Ang-(1-7) levels were significantly decreased, mRNA and protein expressions of ACE2 were significantly decreased, and AT1 expression was significantly increased at days 14 and 28 after vascular balloon injury in the surgery group compared with the control group. PCNA expression was higher in the surgery group than in the control group, and it was significantly decreased after being given rosuvastatin. Expression of ACE2 mRNA and protein, and Ang-(1-7) levels were significantly increased, while AT1 expression and levels of Ang II and P-ERK were significantly decreased in the statin group compared with the surgery group. CONCLUSIONS: Expression of ACE2 mRNA and protein is decreased in the process of intimal thickening after balloon injury. The inhibitory effect of rosuvastatin on intimal thickening is related to upregulation of ACE2, an increase in Ang-(1-7), downregulation of AT1, and activation of the P-ERK pathway.
RESUMO
OBJECTIVE: To investigate the process and mechanism of neointimal formation, the level of angiotensin II and angiotensin (1-7), the expression of angiotensin converting enzyme 2(ACE2), angiotensin II type 1 receptor (AT(1)R), extracellular signal regulated kinase (ERK) and the effects of valsartan on them after aortic balloon injury in rats. METHODS: Aortic endothelial denudation of rats was induced by 2F balloon catheter. Thirty-six rats were randomly allocated into three groups: Group 1 (n = 12): controls; Group 2 (n = 12): aortic balloon injury; Group 3 (n = 12): valsartan (20 mg×kg(-1)×d(-1)) given from 1 day before injury to 14 and 28 days after aortic injury. The expression of ACE2 and AT1, the level of P-ERK, AngII, Ang(1-7) and intimal thickening were investigated by RT-PCR technique, immunohistochemistry, Western blot, radioimmunological method, enzyme linked immunosorbent assay (ELISA) and HE stain, respectively. RESULTS: (1) The proliferation of vascular smooth muscle cells (VSMC) and the intimal thickening were evidenced at day 14 and 28 after aortic balloon injury. (2) The mRNA and protein expressions of ACE2 decreased significantly, but AT(1)R mRNA and protein expression increased significantly at day 14 and 28 after balloon injury. (3) The level of AngII and p-ERK increased and Ang(1-7) reduced after balloon injury. (4) Valsartan not only attenuated the proliferation of VSMC and the intimal thickening but also upregulated the expression of ACE2 and the level of Ang(1-7) and downregulated the expression of AT(1)R and the level of AngII, p-ERK in this model. CONCLUSION: Intimal thickening after balloon injury is linked with reduced expression of ACE2.Valsartan can inhibit the intimal thickening possibly by upregulating ACE2 and Ang(1-7) and downregulating AT(1) in this model.
