Autologous bone marrow-derived endothelial progenitor cell transplantation improves neurological outcomes after cerebral ischemia-reperfusion in rats

Abstract

Objective To investigate the effect of autologous bone marrow-derived endothelial progenitor cell （EPC） transplantation on neurological outcomes in cerebral ischernia in rats and its poss le mechanisms.Methods Autologous bone marrow-derived EPC was cultured in vitro and it was labeled with 5-bromodeoxyuridine （BrdU）.A middle cerebral artery occlusion （MCAO） model was induced by the intraluminal suture method.The rats in a EPC group transplanted autologous EPC （106/ml/kg） via external jugular veins,those in a control group were injected with phosphate buffered saline （1 ml/kg）,and those in a sham operation group （n =15）were not treated.The modified neurological severity score （mNSS） was used to observe the neurological changes of the rats.BrdU immunohistochemical staining was used to evaluate EPC proliferation and differentiation.Three-dimensional confocal image analysis was used to detect the vascular structure and density in cerebral ischemic areas.TUNEL staining was used to detect the apoptotio cells in ischernic brain tissue.Enzyme-linked immunosorbent assay was used to detect the concentration of plasma vascular endothelial growth factor VEGF）.Results The mNSS in the EPC group was siginficantly lower than that in the control group （at day 8：6.43 ±0.69 vs.8.86 ±0.95,q =2.673,P=0.035; at day 14：4.55 ±0.89 vs.6.73 ± 1.06,q =5.360,P =0.035）.The number of BrdU positive cells in the EPC group was significantly higher than that in the control group （42.2±5.76 vs.25.67±5.49,q=4.020,P=0.030）.The capiilary diameter in the EPC group was significantly smaller than that in the control group （4.51 ± 0.21 μm vs.6.34 ± 0.24 μm,q =3.980,P =0.003）; the density of blood vessels （212.64 ± 8.02/0.002 mm3 vs.153.60 ± 7.21/0.002 mm3; q =9.670,P =0.001 ） and the total surface area of microvessel （92 013 ± 5 132 μm2/0.002 mm3 vs. 71 366 ±4 538 μm2/0.002 mm3; q=4.180,P=0.014） were significantly higher or more than those in the control group.The number of apoptotic cells in the EPC group was significantly less than that in the control group （36.26 ± 6.91 vs.78.34 ± 7.21; t =-4.834,P =0.003）.The plasma VEGF concentration in the EPC group was significantly higher than that in the control group （54.91 ± 5.71 pg/ml vs.13.81 ± 4.25 pg/ml,q =12.300,P=0.002）.Conclusions Autologous EPC transplantation has a protective effect on ischemic brain tissue in rats.It may be associated with VEGF related angiogenesis and neuroprotection.It has an important application prospect in the treatment of ischemic cerebrovascular disease. Key words: Brain ischemia; Stem Cells; Endothelium, Vascular; Cell Transplantation; Neovascularization, Physiologic; Vascular Endothelial Growth Factors; Apoptosis; Disease Models, Animal; Rats