Experimental Study Of The Chemotaxis Effect Of Vegf In The Treatment Of Cerebral Ischemia With Bone Marrow Stromal Cells

Objective Bone marrow stromal cells (BMSCs) were separated and cultured in vitro, and was labeled by 5 - bromodeoxyuridine (BrdU). The labeled rate was observed at different time points; Rat model of middle cerebral artery occlusion (MCAO) was prepared using an intraluminal thread technique. TTC Staining and HE staining were applied to determine ischemic area and BMSCs and vascular endothelial growth factor (VEGF) were injected into the cisterna magna. In our study, it is aimed to explore chemotaxis effect of vascular endothelial growth factor (VEGF) in the therapy of bone marrow stromal cells (BMSCs) injection into rats with middle cerebral artery occlusion (MCAO).Methods Primary BMSCs, which were obtained from bone marrow in hindlimbs of two-month-old rats, were amplified in vitro culture and then identified and marked by 5-BrdU in vitro and the labeled rate was observed. The acute cerebral infarction model in rats (n=30), established by using Longa modified method of middle cerebral artery thread occlusion, were perfused 2 hours later. 24h later, 1×106 BMSCs were injected through cisterna magna in both BMSCs treated group (n=10) and BMSCs &VEGF treated group (n=10), while control group was given normal saline through cisterna magna. 20ng VEGF was injected through cisterna magna in the BMSCs & VEGF group, after 48h, 72h and 96h, respertively. Brain tissues were removed from 5 rats after cardiac perfusion in every group at the time of week 1 and week 4. Then these brain tissues were embedded with paraffin and 2 slices with 4um thick were cut near the fontanel area and were dyed by the method of HE staining and bromodeoxyuridine (BrdU) immunohistochemical staining. Positive cells surrounding the infarction areas in different groups by BrdU immunohistochemical staining were observed. Results The labeled rates of BrdU labeled BMSCs were 43%, 58% and 96% at 24h, 48h and 72h. No positive cells were observed at any point of time in the normal saline group. There were more BrdU positive cells surrounding the infarction areas at Week 1 than those at Week 4 in both experimental groups. At Week 1 and Week 4, the number of BrdU positive cells around the infarction areas in BMSCs & VEGF treated group was significantly larger than that in BMSCs treated alone group. P<0.001, with the statistical significance.Conclusion The labeled rate of BrdU labeled BMSCs was higher at 72h, as high as 96%.When BMSCs were injected through cisterna magna of rats with MACO, transplanted cells migrated towards cerebral ischemic areas and the use of exogenous VEGF might be of chemotaxis effect for BMSCs to migrate to cerebral infarction areas.