e0108 Estrogen induces recovery of injured artery endothelium by mobilising endothelial progenitor cell

Introduction Mobilization of endothelial progenitor cells (EPC) restores endothelial function, representing a novel therapeutic direction for injured blood vessel recovery. The present study was designed to determine the effect of oestrogen on EPC mobilisation and regeneration of endothelium in mice. Methods Variectomy is performed before treatment of 17β-oestradiol, 17β-oestradiol combination with oestrogen receptor agonist-ICI182780 and 17β-oestradiol with PI3K blockers- LY294002. Then, carotid artery injury was preformed and neointima was evaluated by H.E staining. 1 and 3 days later, mobilisation of EPCs was evaluated by FACS as double positive of Sca-1/VEGFR-2. Evens blue was injected and area of reendothelization was calculated after 7 days. To trace EPCs in vivo, 1×10 6 autologous spleen-derived EPCs were labelled with DAPI and transplanted through tail vein. Results 1 or 3 days after carotid artery injury, EPCs of peripheral blood were 0.42±0.135% (n=6), 1.47±0.38%(n=5) (ovariectomy+E2); 0.13±0.024% (n=6), 0.25±0.024% (n=6) (ovariectomy); 0.43±0.16%(n=6), 0.65±0.21%(n=4)(non-ovariectomy); 0.12±0.019% (n=6), 0.25±0.062% (n=6) (ovariectomy+E2+LY) and 0.12±0.019% (n=6), 0.24±0.067% (n=6) (ovariectomy+E2+ICI). Area of re-endothelization were (ovariectomy, 28.33±13.49%, n=5) vs (ovariectomy+E2, 69.53±14.14%, n=5) vs (non-ovariectomy, 83.11±7.94%, n=4) (p Conclusion Ooestrogen can induce EPCs mobilisation through ERs/PI3K pathway which is helpful to promote endothelium recovery of injured carotid artery.