Bone Marrow Mesenchymal Stem Cells To Promote Endothelial Repair After Balloon Injury

Objectives To investigate the effect of Mesenchymal stem cells transplation on reparing endothelium injured by the balloon inflation.Methods 24 male Sprague-Dawley(SD)rats underwent balloon overstretch injury in the right common carotid artery.Treatment group: 1ml 5-Brdu labeling MSCs suspension(10~6 cells/ml)were injected into the injuried right common carotid in 12 SD rats.Control group:1ml of phosphate buffered solution(PBS)were injected into injuried right common carotid.Animals were killed at 14 and 28 days after injury in the treatment and control group to assess vessel morphometry and histology.Results:By H-E staining,morphometric analysis at 14 and 28 days showed that MSCs injection after balloon injury significantly reduced neointimal thickening compared with PBS injection after balloon injury (0.57±0.06cm vs 1.09±0.07cm at 14 days,p＜0.05;0.43±0.09cm vs 4.72±0.15cm at 28 days,p＜0.05).Reendothelialization indices were determined by FLK-1 immunohistochemical staining. Reendothelialization was significantly accelerated in the treatment group compared with that in the control group at 14 days and at 28 days ((70.8±1.3)%vs(20.4±1.1)%at 14days,p＜0.05;(90.2±1.3)%vs (10.7±0.4)%at 28 days,p＜0.05).FLK-1 /5-Brdu double masculine cells were 50%in the treatment group.There were significant differences of Reendothelialization in the treatment group at the 14 and 28 days.So were there in the control group.Compared with the control group,the neointima/lumen andα-SMA~+ cells in the neointima was decreased in the treatment group((20.2±0.9)%vs(50.4±1.3)%,(20.2±1.2)%vs (30.7±1.4)%at 14 days;(18.2±0.3)%vs(80.2±1.7)%,(10.1±0.7)%vs (60.9±1.9)%at 28 days).The SMC score statistics difference presented at the 28 days between the treatment and control group,but not at the 14 days.The statistics difference presented in the control group between the 14 days and the 28 days,but not in the treatment group.Conclusion:MSCs has the character of homing to the injured intimal,decreasing the neointima,restraining the transmigration and proliferation of vessel smooth musle cells(VSMC),accelerating the integrity repairing of endothelium.