Bone Marrow Mesenchymal Stem Cell Exosomes Promote Brain Microvascular Endothelial Cell Proliferation and Migration in Rats

  Objective  To study the effect of bone marrow mesenchyml stem cell (BMSC) exosomes (Exo) on the proliferation and migration of brain microvascular endothelial cells in rats.

  Methods  BMSCs were extracted from rats and identified. The BMSCs were co-cultured with bEnd.3 cells in Transwell chamber for 24 h (BMSCs group). Extracted and identified the BMSCs exosomes (BMSC-Exo). Observed and qualitatively evaluated the cells’ abilities on swallowing the BMSC-Exo under a fluorescence microscope. The optimal work concentration of BMSC-Exo was selected by detecting the cell vitality under different BMSC-Exo concentrations by CCK8 method. bEnd.3 cells were co-cultured with BMSC-Exo for 24 h (BMSC-Exo group). bEnd.3 cells cultured alone was set as control group. The proliferation and migration of bEnd.3 cells in the three groups were respectively detected by EDU and cell scratching experiment after 24 h of culture.

  Results  Flow cytometry showed that P3 BMSCs were CD90 and CD29 positive and CD45 negative, with osteogenic differentiation and adipogenesis differentiation, indicating the extracted BMSCs high purity. The BMSC-Exo under transmission electron microscopy was round-shaped with a diameter of about 100 nm; NTA analysis found the diameter distribution of BMSC-Exo ranged from 50 to 600 nm, with a peak size of 150 nm. Immunofluorescence showed that the endothelial cells could swallow BMSC-Exo. CCK8 showed that supplement of 20 μg/mL BMSC-Exo had the best effect on cell proliferation. EDU results showed that BMSCs group and BMSC-Exo group could promote the proliferation of bEnd.3 cells compared with the control group (P<0.05), and there was no difference between BMSCs group and BMSC-Exo group (P>0.05). Cell scratch test showed that the cell mobility of the BMSC-Exo group was higher than that of the control group (P<0.05), but there was no significant difference between the BMSC-Exo group and the BMSCs group (P>0.05).

  Conclusion  BMSC-Exo can replace BMSCs in effectively promoting the proliferation and migration of cerebral microvascular endothelial cells, which provide a new potential treatment for angiogenesis after stroke.