脑源性神经营养因子对体外培养大鼠胚脑皮质神经元缺氧的保护作用

Neuroprotective Effect of BDNF on Hypoxia for Embryonic Rat Cortical Neurons in vitro

目的探讨脑源性神经营养因子（BDNF）对体外培养大鼠胚脑皮质神经元在低氧适应过程的保护作用。方法对胚鼠皮质神经元进行体外培养，观察透射电镜下缺氧诱导大鼠胚脑皮质神经元损伤的超微结构变化；采用MTT比色法检测正常对照组（A组）、不同缺氧时间点皮质神经元缺氧对照组（B组）及缺氧培养前24h和缺氧即刻加入不同剂量外源性BDNF实验组（C组）神经细胞存活率差别；4’、6-二脒基-2-苯基吲哚盐酸染色法结合凋亡细胞的原位末端标记法（TUNEL）检测细胞凋亡。结果遭受缺氧损伤的大鼠胚脑皮质神经元超微结构显示缺氧可以诱导神经细胞坏死、凋亡和混合型细胞死亡；以神经元缺氧最为敏感的0～10h为研究时间，C组在缺氧0～6h时细胞活性显著高于缺氧对照组B组（P〈0．05）。凋亡神经细胞百分率低于缺氧对照组B组（P〈0．05）。结论缺氧可诱导体外培养大鼠胚脑皮质神经元死亡，早期加入外源性BDNF可以使神经元对低氧的耐受性增强而发挥其对神经元的保护作用。

Objective To investigate the neuroprotective function of BDNF on hypoxic- cultured neurons in vitro. Methods The embryonic cerebral cortical neurons of rat were cultured in vitro in hypoxic and non-hypoxic environments and were observed under transmission electron microscope. MTT colorimetry was used to detect the viability of the neurons. Both DAPI colorated measurement and TUNEL methods were used to calculate the percentages of neuron apoptosis. Three groups were designed and compared： Group A - normal control; Group B - exposed to hypoxia; Group C-BDNF intervened （with different dosages and durations） and exposed to hypoxia. Results The ultrastructural alterations of the hypoxic cultured neurons indicated that hypoxia induced necrosis, apoptosis or both. The neurons were most sensitive to hypoxia at the initial 10 hours. At six hours after hypoxic cultures, Group C had significant greater livabillty of neurons and less percentages of neuron apoptosis than Group B （P〈0. 05）. Conclusion Hypoxia damages embryonic cerebral cortical neurons of rat in vitro. Extrinsic BDNF plays a neuroprotective role against hypoxic-induced neurotoxicity in vitro.