Role Of Transforming Growth Factor Beta 1 In The Distribution Of Messenchymal Stem Cells And Neointima Formation Following Vascular Injury

Objective: Morphology of neointima,expression of MSCs markers in neointima were observed and the number of MSCs in peripheral blood and bone marrow in common carotid artery balloon injured model of rats,to explore the role of transforming growth factor beta 1 in the distribution of messenchymal stem cells and neointima formation following vascular injury for further studying mechanism of TGF-β1 affecting the development of neointimal after vascular injury.Methods: Common carotid artery balloon injured model of rats were built.72 male SD rats weighted350g-400 g were randomly assigned into 3 groups: injured common carotid of SB-treated,rh TGFβ1-treated rat and vehicle-treated rat respectively.Every group was randomly assigned into 8 groups underwent left carotid artery balloon injury(0h,8h,1d,3d,7d,14 d,21d,28d).HE staining of vascular injury was used to observe the neointima morphology,immunofluorescence staining and western blotting analysis to observe protein expression of MSCs markers(nestin,CD29),flow cytometry analysis was used to detect the number of MSCs in peripheral blood and bone marrow.Results:(1)The neointima formation in all groups: There were no significant in control,0h,1d,3d groups,obvious neointima were observed in 7d,14,21 d and 28 d groups.The TβRI inhibitor SB-5051242 and active TGFβ1(rh TGFβ1)can inhibite the neointima formation.(2)nestin and CD29 were tested as MSCs markers by immunofluorescence,in the group of injured common carotid of vehicle-treated rat,a greater number of nestin-positive cells observed at 14 days compared to 7 days and 21 days samples.In the group of injured common carotid of SB-treated rat,a small amount of positive cells observed at 21 days and 28 days.In the group of injured common carotid of rh TGFβ1-treated rat,a greater number of positive cells observed at 28 days compared to 14 days and 21 days samples.The result of western blotting about nestin was consistent with immunofluorescence.(3)The numbers of MSCs were significantly elevated in peripheral blood and bone marrow compared to 0 h group in 1 days post injury,and the elevation lasted for14 days.Blocking of TβRI almost abolished the increase in MSCs in peripheral blood at every point post arterial injury.However,in bone marrow the numbers of MSCs were significantly elevated in bone marrow compared to 0 h group within 1 days post injury,and the elevation lasted for 21 days.In the group of injured common carotid of rh TGFβ1-treated rat,the numbers of MSCs were significantly elevated in peripheral blood and bone marrow compared to 0h group in 1 days post injury,and the elevation lasted for14 days.Compared to the vehicle-treated rat,the number of MSCs in 3d and 7d were significantly declined in SB-treated rat in peripheral blood.Conclusion:(1)MSCs can be proliferated and mobilized to peripheral blood and recruited to the remodeling arteries in response to vascular Injury;(2)The SB505124 can inhibit MSCs were mobilized to peripheral blood and the neointima formation;(3)The mechanism of rh TGFβ1 in the recruitmen of MSCs and neointima formation may be different by topical and systemic injection.