不同剂量血管内皮生长因子在低氧环境下可保护神经干细胞

Protective effects of different doses of vascular endothelial growth factors on neural stem cells under hypoxic environment

背景:血管内皮生长因子是一种可以促进血管形成的细胞因子,近来有动物实验及临床研究显示其在急性缺血性卒中以及脊髓损伤组织中表达增加,可抑制细胞凋亡,但具体作用机制尚不明确。目的:以不同剂量血管内皮生长因子干预低氧环境诱导的神经干细胞,观察其保护作用,并探索其作用机制。方法:分离培养胎鼠大脑皮质神经干细胞,随机分为空白对照组、缺氧组以及低、中、高剂量血管内皮生长因子组。空白对照组在体积分数35%氧气环境培养24 h,缺氧组以及低、中、高剂量血管内皮生长因子组在体积分数3%氧气环境培养24 h,低、中、高剂量血管内皮生长因子组培养基中分别加入20,40和80μmol/L血管内皮生长因子。CCK-8法、TUNEL法检测各组细胞增殖和凋亡情况,Western blot检测神经细胞凋亡相关蛋白的表达水平。结果与结论:与空白对照组相比,缺氧组神经干细胞增殖能力下降,凋亡细胞数量明显增加,且细胞中Bcl-2和核因子κB表达水平下降,Bax和TWIK相关的酸敏感钾离子通道蛋白表达水平增加,而不同剂量的血管内皮生长因子都能抑制上述现象,其中40μmol/L血管内皮生长因子的作用效果最为显著。结果说明血管内皮生长因子能通过干预凋亡相关蛋白表达而影响细胞凋亡,进而发挥神经保护作用,且40μmol/L血管内皮生长因子效果最强。

BACKGROUND: Vascular endothelial growth factor(VEGF) is a cytokine which can promote angiogenesis.Recently, some animal experiments and clinical studies have shown that VEGF expression is increased in acute ischemic stroke and spinal cord injury, which can inhibit cell apoptosis, but the mechanism is not clear.OBJECTIVE: To intervene in hypoxic-induced neural stem cells with different doses of VEGF, and to explore the protective effects and mechanism of VEGF.METHODS: Neural stem cells was obtained from the cerebral cortex of a fetal rat, which were randomly divided into blank control group, hypoxia group and low-, medium-and high-dose VEGF groups. The cells in the blank control group were cultured for 24 hours under 35% oxygen. The cells in the other four groups were cultured for 24 hours under 3% oxygen. In the low-, medium-and high-dose VEGF groups, 20, 40 and 80 μmol/L VEGF were supplemented into the medium, respectively. The proliferation and apoptosis of the cells were detected by cell counting kit-8 method and TUNEL method. The expression level of nerve cell apoptosis related proteins was detected by western blot.RESULTS AND CONCLUSION: Compared with the blank control group, the proliferation of neural stem cells decreased, the number of apoptotic neural stem cells was increased significantly, the expression levels of Bcl-2 and nuclear factor κB in the cells were decreased, and the expression levels of Bax and TWIK were increased in the hypoxia group. VEGF at all the three doses could inhibit these phenomena, and 40 μmol/L VEGF showed the best efficacy. These results indicate that VEGF can affect cell apoptosis by interfering with the expression of apoptosis-related proteins, and then exert neuroprotective effects, especially at 40 μmol/L.