Angiotensin-(1-7) Suppresses The Number And Function Of The Circulating Fibrocytes By Upregulatin Endothelial Nitric Oxide Synthase Expression

Objective The purpose of this study was to examine the direct effect of Angiotensin-(1-7)[Ang-(1-7)] on CFs.Method Total mononuclear cells (MNCs) were isolated from peripheral blood by Ficoll density gradient centrifugation. Using laser scanning confocal microscopy, CFs were identified as adherent cells that stained positive for both CD34and collagen-Ⅰ. After14days of culture, CFs were stimulated with Ang-(1-7) at concentrations of10nM,100nM,1μM or10μM, in the absence and presence of pretreatment with A-779, NG-nitro-L-arginine methyl ester (L-NAME) or both, for24,48or72h. The number of cells, cellular proliferation and level of apoptosis were determined by hematoxylin and eosin staining, the Cell Counting Kit-8(CCK8) assay and the annexin V/propidium iodide binding assay, respectively. The collagen content of CFs was measured by the concentration of hydroxyproline, which was detected using the enzymatic digestion method. The expression of endothelial nitric oxide synthase (eNOS) was assayed by western blot analysis, while nitric oxide (NO) generation was detected using the Griess method.Results We found that Ang-(1-7) increases apoptosis and eNOS/NO production in CFs. In addition, Ang-(1-7) decreases the number, proliferative capacity and collagen-secretion of CFs in a concentration-and time-dependent manner.Conclusion These data suggest that Ang-(1-7) suppresses the function of CFs possibly by increasing eNOS/NO production in the CFs.