Genomics Division, Biologics and Genetic Therapies Directorate, Health Canada, 251 Sir Frederick Banting Driveway, A/L 2201E, Ottawa, ON, K1A 0K9, Canada.
J Mol Neurosci. 2011 Mar;43(3):428-42. doi: 10.1007/s12031-010-9461-7. Epub 2010 Oct 15.
Preconditioning and postconditioning are mild ischemic exposures before or after severe injurious ischemia, respectively, that elicit endogenous neuroprotective responses. Molecular mechanisms of neuroprotection through preconditioning and postconditioning are not completely understood. Here we optimized the in vitro oxygen and glucose deprivation (OGD) models of preconditioning and postconditioning in primary cortical neuron cultures that allow the studies of the corresponding molecular mechanisms of neuroprotection. We found that the cortical cells preconditioned with a single 45-min OGD treatment administered 24 h prior to injurious 2 h OGD were robustly protected after both 3 h and 16 h of reperfusion. For the postconditioning treatment, we found that three cycles of 15 min OGD followed by 15 min reperfusion, applied immediately after injurious 2 h OGD and prior to complete reperfusion, resulted in effective neuroprotection at both 3 h and 16 h of reperfusion. Using real-time RT-PCR arrays focused on genes of the apoptosis and PI3K-Akt pathways, we found that injurious OGD mainly induced apoptosis-related and repressed PI3K-Akt pathway-related genes after either 3 h or 16 h of reperfusion. Preconditioning treatment resulted in the activation of both pro-survival and anti-apoptotic pathways after 3 h of reperfusion and mainly anti-apoptotic pathway after 16 h of reperfusion. In contrast, the activation of PI3K-Akt pathway mainly contributed to the neuroprotective effect by the postconditioning treatment after 3 h of reperfusion, but differential gene expression likely contributed minimally, if at all, to the neuroprotection observed after 16 h of reperfusion. Among the novel markers of neuroprotection, Nol3 gene upregulation was observed after 3 h of reperfusion following either preconditioning or postconditioning treatments and after 16 h of reperfusion following preconditioning treatment.
预处理和后处理分别是指在严重损伤性缺血之前或之后进行的轻度缺血暴露，它们可以引发内源性神经保护反应。预处理和后处理的神经保护分子机制尚未完全阐明。在这里，我们优化了原代皮质神经元培养物中的体外氧葡萄糖剥夺（OGD）预处理和后处理模型，从而可以研究相应的神经保护分子机制。我们发现，皮质细胞在损伤性 2 小时 OGD 前 24 小时进行单次 45 分钟 OGD 预处理后，在 3 小时和 16 小时再灌注时均得到了强烈的保护。对于后处理治疗，我们发现，在损伤性 2 小时 OGD 后立即并在完全再灌注之前，进行三个循环的 15 分钟 OGD 随后 15 分钟再灌注，可在 3 小时和 16 小时再灌注时均有效保护神经。使用针对凋亡和 PI3K-Akt 途径的基因的实时 RT-PCR 阵列，我们发现，在 3 小时或 16 小时再灌注后，损伤性 OGD 主要诱导凋亡相关基因的表达下调和 PI3K-Akt 途径相关基因的表达下调。预处理处理在 3 小时再灌注后导致了促生存和抗凋亡途径的激活，而在 16 小时再灌注后主要是抗凋亡途径的激活。相比之下，PI3K-Akt 途径的激活主要在 3 小时再灌注后通过后处理治疗对神经保护产生作用，但基因表达的差异可能在 16 小时再灌注后对观察到的神经保护作用贡献极小，甚至没有贡献。在神经保护的新标记物中，在预处理或后处理后 3 小时再灌注后观察到 Nol3 基因上调，在预处理后 16 小时再灌注后也观察到 Nol3 基因上调。
