一氧化氮合酶与缺氧复氧所致神经细胞凋亡及银杏叶提取物的保护作用

目的　探讨一氧化氮 (NO)在缺氧复氧诱导神经细胞凋亡中的作用及中药银杏叶提取物的保护机制。方法　实验使用胎龄 16～ 17日Wistar大鼠的大脑皮层神经细胞进行原代分离培养 ;采用Wright Giemsa染色 ,光镜、透射电子显微镜观察 ;原位末端标记法确立缺氧复氧神经细胞凋亡病理模型 ;应用NADPH d组织化学方法检测神经细胞一氧化氮合酶 (NOS)的表达并用计算机图像分析系统进行定量检测。　结果　缺氧复氧可以使大鼠大脑皮层神经细胞发生凋亡 ,随缺氧时间的延长 ,凋亡细胞数渐多 ,至缺氧 8h复氧 18h达高峰 ;在缺氧 2h(H2 R0 组 )和缺氧 8h复氧 18h(R8R1 8)组中神经细胞NOS表达均显著增高 ,与正常对照组比有显著性差异 (P <0 0 1;P <0 0 5 )。EGB能显著抑制此双时相NOS活性的增强 ,并明显降低神经细胞凋亡率。　结论　缺氧复氧损伤可诱导培养的大鼠大脑皮层神经细胞发生凋亡。NOS表达增强从而使NO产生增加可能是缺氧复氧诱导神经细胞凋亡的机制之一。银杏叶提取物 (EGB)经下调NOS表达活性 ,抑制NO的产生保护培养的大鼠大脑皮层神经细胞免于凋亡。

THE EXPRESSION OF NOS IN THE APOPTOSIS OF NEURONS FOLLOWING HYPOXIA/REOXYGENATION AND THE PROTECTIVE EFFECT OF EGB

Objective To investigate the dynamic expression of nitric oxide synthase(NOS) in the apoptosis of primary cultured rat cortical neruons following hypoxia/reoxygenation(H/R) and the protective role of extract of ginkgo biloba(EGB). Methods The cortical neurons of E16-17 days fetal rat were primarily cultured.The apoptosis model of primary cultured cortical nurons following H/R was established by using W-G staning,electromicroscopy,TUNEL staining.The dynamic expression of NOS different H/R times was investigated with NADPH-diaphorase histochemical method. Results H/R can cause apoptosis of primary cultured rat cortical neurons.In the experiment of H-2R-0,H-4R-0, H-6R-0,H-8R-0 and H-2R 18,H-4R 18,H-6R 18 H-8R 18,the apoptosis cells occurred after 4 hour hypoxia.The increasing of apoptosis cell acted as time-dependence and the peak value was at H-8R 18.The expression of NOS increased both after 2 hour hypoxia and reoxygenation 18 hour after 8 hour hypoxia compared with the normal control group.EGB could inhibit the increasing and decrease the percentage of apoptosis.Conclusion The apoptosis of primary cultured rat cortical neurons could be induced by H/R.The increasing of NO might be one of the mechannisms of apoptosis.EGB could singnificantly inhibit the apoptosis by means of inhibiting the expression of NOS and reducing the production of NO.;