Human Umbilical Cord Blood Mesenchymal Stem Cells Transplantation Improves Inflammatory Responses In Ischemic Stroke Rats

Objective To investigate the effect of human umbilical cord blood mesenchymal stem cells(h UCB-MSCs) on expression of inflammatory cytokine, regulatory T cell(Treg), and neurologic deficits in ischemic stroke rats.Methods In total of forty male SD rats were randomly assigned into four groups: ischemia-reperfusion group, h UCB-MSCs transplanted group, normal saline-treated group, sham group, ten in each group. 100 ml cord blood from full-term inants who were informed maternal consent was collecting in aseptic conditions. h UCB-MSCs were separated in vitro. The rat ischemic model was created by middle cerebral artery occlusion(MCAO). 1×106 h UCB-MSCs were injected slowly via the tail vein in the h UCB-MSCs group. For the saline group, 1ml saline without h UCB-MSCs were injected in the same way. To assess the effect of h UCB-MSCs on inflammatory response, their serum levels of IL-6, IFN-γ, IL-10 and TGF-β were measured before ischemia, 30 min after ischemia, and 2,3,6 h after reperfusion. Their nerve function was scored and expression of regulatory T cells in peripheral blood was detected on days 1,3,7 and 14 respectively after reperfusion.Results The serum IL-6 and IFN-γ level increased and reached its peak at 2h after reperfusion and 30 min after ischemia respectively, and was significantly lower in IR+h UCB-MSCs group than in IR group and IR+NS group. The serum IL-10 and TGF-β level decreased in IR group and IR+NS group and increased in IR+h UCB-MSCs group after reperfusion. The nerve function defect score was significantly lower in IR+h UCB-MSCs group than in IR group and IR+NS group on days 3,7 and 14 after reperfusion. The regulatory T cells increased significantly in IR group and IR+NS group than SH group on days 7 and 14 after reperfusion, while the expression of Treg was higher in IR+h UCB-MSCs group than in IR group and IR+NS group on days 3,7 and 14 after reperfusion(P<0.05).Conclusion h UCB-MSCs transplantation can ameliorate ischemic brain injury by promoting the recovery of neurologic deficits, inducing the proliferation of CD4+CD25+ regulatory T cells, decreasing the IL-6 and IFN-γ level, and increasing the IL-10 and TGF-β level.