Transplantion Of Bone Mesenchymal Stem Cells Combinated With Endothelial Progenitor Cells For Treatment Of Rat's Cerebral Ischemia Injury

ObjectiveTo compare the transplantation of BMSCs combinated with EPCs with the transplantation of BMSCs or EPCs for treatment of ischemic cerebrovascular disease, in order to investigate the effect of BMSCs combinated with EPCs transplantation on promoting functional improvement for treatment of rat's cerebral ischemia injury and its mechanism of action.MethodsWe obtain BMSCs by entire medulloculture and cell adherence culture, and gain EPCs by density gradient centrifugation and cell adherence culture. Rat middle cerebral artery occlusion (MCAO) model was established. A total of 80 SD rats were divided into model group, PBS group, BMSCs group, EPCs group and cell combination group at random. Through external carotid artery 24 hours after transient MCAO, 2 x 10(6) BMSCs combinated with 2 x 10(6) EPCs were transferred into cell combination group, 2 x 10(6) BMSCs was transferred into BMSCs group, 2 x 10(6) EPCs was transferred into EPCs group, and the same volume of PBS was transferred into PBS group, respectively.In addition, sham operated group had 8 rats. Behavioral tests, cell morphosis and infarction volume were investigated at 4 weeks after MCAO. The expression of Brain-derived neurotrophic factor(BDNF) in ischemic border zone was evaluated by immunohistochemistry. Results1. The scores of neurologic function: The sham operated group was the same as normal SD rats. The score of model group, PBS group, BMSCs group, EPCs group and cell combination group were 3.56±0.37, 3.71±0.18, 2.34±0.10, 2.41±0.06, 1.12±0.29, respectively. Cell transplantation groups of the scores of neurologic function was markly different to model group or PBS group(P<0.05). The score of cell combination group was significantly fewer than that in the other group(P<0.05).2. Infarction volume: The infarction volume of model group, PBS group, BMSCs group, EPCs group and cell combination group were 199.38±15.67 mm3, 192.12±17.63mm3, 141.00±12.51mm3, 108.12±9.54mm3, 84.75±12.85 mm3. Cell transplantation groups of reducing infarction volume was markly different to model group or PBS group(P<0.05). The cell combination group reduced infarction volume significantly more than that in the other group(P<0.05).Compared with BMSCs group's infarction volume, that of EPCs group had statistical significance (P<0.05).3. The expression of BDNF in ischemic border zone: The cell number of expressing BDNF of model group, PBS group, BMSCs group, EPCs group and cell combination group was 3.51±0.54, 5.10±0.39, 32.46±3.11, 16.32±2.84, 58.69±8.37. By statistical analysis, The cell transplantation group of increasing expression of BDNF was markly different to model group or PBS group(P<0.05). The cell combination group increased expression of BDNF significantly more than that in the other group(P<0.05). Compared with BMSCs group's expression of BDNF, that of EPCs group had statistical significance(P<0.05).Conclusion1. Compared with BMSCs group and EPCs group, cell combination group has an advantage on the treatment of cerebral ischemia injury.2. The treatment for cerebral ischemia injury though transplanting BMSCs combinated with EPCs may had two possible protective mechanism. On one hand, transplanted BMSCs increased the expression of BDNF, which participate brain cell's regeneration in ischemic region; On The Other Hand, transplanted EPCs promote the increase of vascular angiogenesis in ischemic border zone, which improved ischemic region's blood supply.