| [Background]The restenosis following angioplasty and stenting limited the long term outcome of endovascular therapy.Both endothelial cells(ECs)damage and vascular smooth muscle cells(VSMCs)proliferation are participated in pathological process of restenosis following angioplasty and stenting.Exosomes released from endothelial progenitor cells(EPCs)play a role of protection in various disease models.But the effect of exosomes on the restenosis following angioplasty and stenting,and on both ECs and VSMCs is still not too much.[Objective].In this study,we sought to investigate the effect of exosomes released by EPCs derived from human fetal aorta(HFA)to the rat carotid artery balloon injury model in vivo and to both ECs and SMCs in vitro.[Methods]Exosomes isolated from the conditioned media of EPCs derived from human fetal aorta(HFA)were confirmed by transmission electron microscopy and western blot.The in vivo model of restenosis following endovascular therapy was examined by the rat carotid balloon injury model.The exosomes were injected into that experimental animal model in the Exo group while the equal volume of saline was injected in the control group(Con group).Then the model rats were sacrificed on 2,4,14 and 28 days and the specimens of injured carotid artery were collected for Even blue examination,HE staining and immunohistochemistry.The in vivo effects of exosome on both re-endothelialization and neointimal formation were measured.The in vitro effect of exosomes on the proliferation and migration of both endothelial cells and vascular smooth muscle cells were investigated through CCK-8 cells proliferation assay and wound healing assay.[Results]Between the Con group and the Exo group,the Even blue results showed that the re-endothelial area was not significantly different on 2 days(5.64 ± 2.19%in Con group versus 6.06 ± 1.99%in Exo group;n=6;P=0.74)and 4 days(6.21 ± 2.03%in Con group versus 7.42 ± 2.6%in Exo group;n=6;P=0.4).While in the early time,the HE result showed that the intimal/medial area ration(I/M)was slightly higher in the Exo group on 2 days(0.44 ± 0.05%in Con group versus 0.56 ± 0.14%in Exo group;n=6;P=0.07)and 4 days(0.64 ± 0.15%in Con group versus 0.76 ± 0.30%in Exo group;n=6;P=0.36),although the difference was not significant.The integrated optical density(DOI)examined by immunohistochemistry showed that the proliferation of SMCs was slightly high in the Exo group on 2 days(7841.67±1994.22 in Con group versus 9212.51±2671.11 in Exo group;n=6;P=0.338)and 4 days(8834.26±1198.51 in Con group versus 10715.14±1782.43 in Exo group;n=6;P=0.058),but the difference was not significant.The re-endothelial area of Con group was significantly smaller than that of Exo group on 14 days(46.86 ± 12.89%in Con group versus 80.77 ± 13.42%in Exo group;n=6;P<0.05)while the re-endothelization of the carotid artery were well in both groups on 28 days(92.04 ± 5.91%versus 93.82 ± 5.29%;n=6;P=0.59).The I/M in Exo group was significantly smaller than that in Con group on 14 days(1.671±0.267 in Con group versus 0.836±0.298 in Exo group;n=6;P<0.05)and 28 days(2.152±0.212 in Con group versus 1.379±0.287 in Exo group;n=6;P<0.05).The immunohistochemistry result showed proliferation of VSMCs was significantly higher in the Exo group compared to the Con group on 14 days(35833.25±2971.31 in Con group versus 23942.52±2070.68 in Exo group;n=6;P<0.05)and 28 days(54313.50±5245.53 in Con group versus 30695.34±3795.34 in Exo group;n=6;P<0.05).In the in vitro study,the exosomes could significantly enhance the proliferation and migration of both ECs and VSMCs.[Conclusion]Exosomes derived from EPCs could inhibit neointimal hyperplasia following carotid artery injury in rats.The protective effect of exosomes may through the promotion of endothelial cell repair but not through the direct suppression of proliferation and migration of vascular smooth muscles cells. |
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