银杏内酯B抗缺血神经元凋亡的预适应作用

The preconditioning effect of ginkgolide B against ischemia-induced apoptosis in cultured cortical neurons

目的研究银杏内酯B(Ginkgolide B,GB)对缺血引起的神经元凋亡的影响,并从预适应角度探讨其可能的机制。方法原代培养的小鼠皮层神经元,经过短时缺血预适应(1%O2,无糖DMEM)或GB预处理(120μmol/L,24h)后,再进行严重缺血损伤,通过MTT比色法观察细胞的活性,Hoechst 33342荧光染色检测细胞的凋亡;Western-blot分析磷酸化糖原合成酶激酶-3β(phosphorylated glycogen synthase kinase-3β,p-GSK-3β)和活化的Caspase-3蛋白表达量的变化。结果神经元缺血后活性下降,凋亡比率增高;缺血预适应或银杏内酯B预处理可提高缺血神经元p-GSK-3β的表达,抑制Caspase-3的活化,提高缺血神经元的活性,降低凋亡比率。结论银杏内酯B对缺血诱导的神经元凋亡具有拮抗作用,其作用机制与缺血预适应相似,两者均能提高p-GSK-3β的表达,抑制Caspase-3的活化,银杏内酯B对神经元可发挥药理性预适应作用。

Objective To observe the effects of ginkgolides B （GB） on the ischemia-induced neuronal apoptosis and explore its mechanisms in the aspect of the preconditioning. Methods Primary cultured cortical neurons were pre-treated with GB （120μmol/L） for 24h or ischemia（ DMEM without glucose, 1% O2 ） for 1 h and then exposed to 21% O2 and complete DMEM for 24h before the cells were treated with ischemia for 5h. Neuronal viabilities were assessed by MTT assay. Apoptosis was determined by Hoechst 33342 fluorescent staining to the nuclei of cuhured neurons. The phosphorylated gly- cogen synthase kinase-3 β （p-GSK-3β） and active Caspase-3 proteins in neurons were measured by Western blot analysis. Results GB and IP significantly reduced ischemia-induced neuronal injury. GB and IP obviously increased cell viabilities and expression of p-GSK-3β ,markedly decreased levels of active Caspase-3 and percentage of apoptosis in ischemic neurons. Conclusion GB is capable of preconditioning like IP against ischemia-induced apoptosis in neurons by increasing the expression of p-GSK-3β and decreasing the level of active Caspase-3. The study implies GB have the role of pharmacological preconditioning in preventing high-risk disease such as stroke.