中文摘要：

目的：利用N-甲基-D-天门冬氨酸（NMDA）诱发新生小鼠脑皮质神经元损伤模型,探讨神经活性甾体别孕烯醇酮对脑皮质神经元的保护作用及其机制。方法：应用RT-PCR和Western blot法检测别孕烯醇酮对β2-γ-氨基丁酸受体（β2-GABA-R）表达和对蛋白激酶B（PKB,又称为Akt）磷酸化的影响。应用Western blot和DNA-Ladder方法检测NMDA诱发的神经元凋亡及别孕烯醇酮对NMDA诱发凋亡的影响。结果：Western blot和RT-PCR分析表明0.5×10-6mol/L-5×10-6mol/L别孕烯醇酮使Akt磷酸化增加并促进β2-GABA-R mRNA的表达。1×10-6mol/L别孕烯醇酮预处理小鼠脑皮质神经元有抗凋亡作用,但5×10-6mol/L别孕烯醇酮预处理小鼠脑皮质神经元使NMDA诱发的DNA-Ladder减弱明显,并能有效抵抗NMDA诱发的活化型PRAP、Caspase-3、Caspase-9的增加。结论：别孕烯醇酮可通过促进β2-GABA-R表达和增加Akt磷酸化抵抗NMDA诱发的脑皮质神经元凋亡。

英文摘要：

Objective：To investigate the protective mechanism of neuroactive steroid allopregnanolone on N-methyl-D-aspartate（NMDA） induced toxicity in primary mouse cortical neurons.Methotls：Primary cultured mouse cortical neurons were subjected to allopregnanolone,the expression of β-aminobutyric acid receptor β2 subunit（β2-GABA-R） mRNAs was detected by RT-PCR and Akt phosphorylation was assayed by Western blot using Akt-phosphoserine 473-specific antibody.After the cultured mouse cortical neurons were pretreated with or without allopregnanolone prior to treatment with NMDA,DNA isolated was analyzed by agarose gel electrophoresis and proteins collected were analyzed by Western blot with anti-cleaved-PARP,anti-cleaved caspase-3,and anti-cleaved caspase-9 antibodies.Results：When cultured mouse cortical neurons were exposed to allopregnanolone both the expression of β2-GABA-R mRNAs and Akt phosphorylation increased.Allopregnanolone inhibited the NMDA-induced apoptosis and decreased the level of active-PARP,active-caspase-3 and active-caspase-9 notably at a final concentration of 5×10-6mol/L.Conclusion：Pretreatment with allopregnanolone may be neuroprotective on NMDA-induced neuronal cells apoptosis by increasing β2-GABA-R expression and Akt phosphorylation.