缺氧条件下间充质干细胞以旁分泌方式影响脑微血管内皮细胞的功能

目的：探讨缺氧条件下间充质干细胞（MSCs）以旁分泌方式对脑微血管内皮细胞（BMECs）的增殖、迁移和细胞单层通透性的影响。 方法:分离、培养并鉴定人MSCs和大鼠BMECs，ELISA检测细胞条件培养基中VEGF和MMP-9的含量，跨内皮电阻（TEER）检测反映脑BMECs单层通透性的变化，观察不同条件培养基对缺氧BMECs增殖、迁移和通透性的影响。结果:VEGF和MMP-9在MSCs条件培养基中的含量显著高于BMECs条件培养基，缺氧处理的MSCs条件培养基中VEGF和MMP-9含量比正常MSCs条件培养基显著增高；MSCs条件培养基能明显促进BMECs在缺氧条件下的增殖和迁移，但也使BMECs的TEER显著降低（50.5％±2.6％，P<0.05），这些作用在不同程度上能被VEGF抗体和MMP-9抑制剂所抑制。结论:缺氧条件下MSCs可通过旁分泌方式促进BMECs增殖和迁移，但同时也增加了BMECs单层的通透性。

Paracrine actions of mesenchymal stem cells to the function of brain microvascular endothelial cells in hypoxic conditions

AIM: To investigate the paracrine actions of mesenchymal stem cells (MSCs) to brain microvascular endothelial cells (BMECs) in hypoxic conditions. METHODS: Human bone marrow MSCs and rat BMECs were isolated, cultured and identified. The contents of VEGF and MMP-9 were confirmed using ELISA assays of the conditioned media. The transendothelial electrical resistance (TEER) was detected to reflect the permeability of the BMECs monolayer. The effects of different conditioned media on BMECs were investigated in hypoxic conditions. RESULTS: The contents of VEGF and MMP-9 in conditioned media were induced to increase significantly by the hypoxic stress, which were much lower in BMECs conditioned media than that in MSCs conditioned media. Hypoxia induced a significant increase in VEGF and MMP-9 in MSCs conditioned media collected in comparison to those in normal conditions. In hypoxic conditions, MSCs conditioned media enhanced the proliferation (optical density values: 0.947±0.103 vs 0.254±0.024, P<0.01, n=6) and migration (migration cells number: 238±27 vs 95±17, P<0.01, n=6) of BMECs significantly, simultaneously decreased the TEER of the BMECs monolayer strikingly (50.5％±2.6％of original, P<0.05,n=3). These effects were partly inhibited by both anti-VEGF antibody and MMP-9 inhibitor. CONCLUSION: In hypoxic conditions, MSCs enhance the proliferation and migration of BMECs significantly through paracrine, simultaneously increase the permeability of the BMECs monolayer strikingly.