Experimental Study On The Treatment Of Brain Infarction By Mobilizing Endothelial Progenitor Cells

Objective: To establish mouse focal MCAO/R model by the method of thread thrombus. To observe the change of number of endothelial progenitor cells(EPCs) in peripheral circulation after acute MCAO/R and evaluate treatment of mouse brain infarction after acute MCAO/R by VEGF through mobilizing bone marrow-derived EPCs.Methods: After establishing mouse MCAO/R model, we injected VEGF intraperitoneally to mobilize bone marrow-derived EPCs once a day for one week. On the first, fourth and seventh day during mobilization, neurological functions were evaluated before mice were sacrificed, thereafter, blood samples were taken from angular vein. Then we detected the number of EPCs in peripheral circulation in MCAO/R+VEGF group and MCAO/R group using flow cytometry. Finally, mice were decapitated and brains sliced and stained with TTC. Infarct volumes were calculated and compared among groups.Results: MCAO/R increased the number of EPCs in peripheral circulation, which had significant difference between MCAO/R group and control group on the first day after operation(p＜0.01), but the number of EPCs decreased gradually; EPCs in MCAO/R+VEGF group began to increase on the first day after treatment, and reached its peaked on the fourth day and sustained to the seventh day, while number of EPCs in MCAO/R+VEGF group had significant difference between the other groups(p＜0.01). Neurological functions improved significantly in both MCAO/R+VEGF group and MCAO/R group on the seventh day compared with that on the fourth day (p＜0.05), and the neurological functions improved significantly as early as the fourth day after operation in MCAO/R+VEGF group compared with that on the first day after operation(p＜0.05). It showed significant difference when neurological functions were compared between MCAO/R+VEGF group and MCAO/R group on the fourth day and seventh day respectively(p＜0.05). After TTC staining, infarct volume was calculated using specific image analyzing system. Infarct volume decreased significantly in MCAO/R+VEGF group on the fourth day compared with that on the first day (p＜0.01) and as is the case on the seventh day compared with that on the day fourth day (p＜0.01). It showed significant difference when infarct volumes were compared between MCAO/R+VEGF group and MCAO/R group on the fourth day and the seventh day respectively(p＜0.01), infarct volume in MCAO/R+VEGF group was smaller than that in MCAO/R group.Conculsions: The ischemia and reperfusion time of the mouse focal MCAO/R model established by the method of thread thrombus can be controlled accurately. This model can imitate the pathophysiology of ischemia-reperfusion in the middle cerebral artery of human ischemic cerebrovascular disease. In the state of acute MCAO/R, bone barrow-derived EPCs can be mobilized to help the recovery of injury. VEGF can mobilize EPCs in mouse bone barrow. The mobilized EPCs can increase angiogenesis to decrease infarction area and treat brain infarction.