Effects of angiotensin Ⅱ and its receptor blockers on migration and endothelin-1 expression of rat vascular adventitial fibroblast subpopulations

The study is to investigate the effect of angiotensin Ⅱ (Ang Ⅱ) and its receptor blockers on migration and endothelin-1 (ET-1) expression of rat vascular adventitial fibroblast subpopulations.  Vascular adventitial fibroblasts were individually expanded by using cloning rings, and the effects of Ang Ⅱ on the migration of adventitial fibroblast subpopulations were evaluated by Transwell.  Fluorescence quantitative-PCR detected the expression of preproET-1 mRNA induced by Ang Ⅱ, and its receptor antagonists losartan and PD-123319.  The concentration of ET-1 was determined by ELISA.  It showed that spindle shaped and epithelioid shaped cells were isolated by using cloning rings, named as spindle cells and round cells.  RT-PCR showed that fibroblast subpopulations did not have leukocytes, endothelial cells and smooth muscle cells, namely pure cell lines.  Compared with respective control cells, two subpopulations had transferring ability.  Ang Ⅱ significantly improved round cells migration in a concentration-dependent manner, and had no obvious influence on spindle cells migration.  Ang Ⅱ (1×10⁻⁸ − 1×10⁻⁶ mol·L⁻¹) significantly increased the expression of preproET-1 mRNA in round cells (P < 0.01), and had no significant effect on the expression of preproET-1 mRNA in spindle cells.  Losartan blocked the expression of preproET-1 mRNA induced by Ang Ⅱ in round cells, and had no significant effect on the expression of preproET-1 mRNA in spindle cells.  The effects of Ang Ⅱ and ET-1 receptor inhibitors on the release of ET-1 were similar to the expression of preproET-1 mRNA.  The results indicate that there are two cell subpopulations: round cells and spindle cells in rat vascular adventitial fibroblasts.  Ang Ⅱ significantly improved cells migration, and increased the expression of ET-1 in round cell subpopulation.  It suggested that there may be different migratory mechanisms in two cell subpopulations, and the two subpopulations may play a different role in vascular remodeling and reparative process.