慢性低O2高CO2对大鼠海马Bcl-2、Bax基因表达和细胞凋亡的影响

目的：探讨慢性低O2高CO2对大鼠海马神经细胞凋亡的诱发作用及对Bcl-2、Bax基因表达的影响。方法：雄性SD大鼠50只,随机均分成5组：正常对照组（NC）、低O2高CO21周组（1HH）、2周组（2HH）、3周组（3HH）和4周组（4HH）。采用TUNEL法检测海马神经细胞凋亡;以RT-PCR检测海马Bcl-2mRNA和BaxmRNA的表达。结果：随着低O2高CO2时间延长,凋亡指数（AI）及BaxmRNA水平进行性升高;Bcl-2mRNA先升高后下降（均P〈0.01）。AI与BaxmRNA之间呈显著正相关（r=0.814,P〈0.01）,而与Bcl-2mRNA/BaxmRNA比值之间呈显著负相关（r=-0.405,P〈0.01）。结论：慢性低O2高CO2可以诱发大鼠海马神经细胞凋亡,Bcl-2/Bax比值下降是促进凋亡的重要因素。

Effect of Chronic Hypoxic Hypercapnia on the Expression of Bcl-2 and Bax Genes and Apoptosis in Rat Hippocampal Cells

Objective: To explore the inducing effect of chronic hypoxic hypercapnia on the apoptosis of rat neural cells in the hippocampus, and the relationship between the apoptosis and Bcl-2 as well as Bax gene expression. Methods: Fifty male spragu-dawley rats were randomly divided into five groups: normal control group (NC), hypoxic hypercapnia 1-week (1HH), 2-week (2HH), 3-week (3HH) and 4-week (4HH) group. The in situ cell apoptosis in the hippocampus was detected with TUNEL staining. The expression of Bcl-2 and Bax mRNA in the hippocampus were examined with RT-PCR. Results: Apoptosis index (AI) and the expression Bax mRNA were progressirely increased with the prolongation of duration of hypoxic hypercapnic exposure, and the expression of Bcl-2 mRNA was increased at first, then declined. There was a significant positive correlation between AI and the expression of Bax mRNA (r=0.814, P<0.01), and there was a significant negative correlation between AI and the ratio of Bcl-2 mRNA/ Bax mRNA (r=-0.405, P<0.01). Conclusion: Apoptosis can be induced by chronic hypoxic hypercapnia in rat hippocampus. The ratio of Bcl-2/Bax decline accelerates the occurrence of apoptosis.