亚低温减轻氧糖剥夺所致的大鼠海马神经元损伤

Mild hypothermia protects against injury of rat hippocampal neurons induced by oxygen-glucose deprivation

目的:研究亚低温(31～32℃)对氧糖剥夺(OGD)损伤的大鼠海马神经元的保护作用并探讨其保护机制。方法:本实验通过体外培养大鼠海马神经元并予以OGD处理,建立了模拟大脑缺血、缺氧的神经元OGD模型;将实验细胞随机分为正常对照组、单纯亚低温组、单纯OGD组以及亚低温+OGD组,通过形态学观察、神经元凋亡率检测以及胞浆内caspase-3活性检测,研究亚低温对神经元OGD的保护作用及其机制。结果:神经元OGD后出现明显的细胞损伤,凋亡率明显升高(P<0.01);与单纯OGD组比较,亚低温+OGD组细胞损伤明显改善,细胞形态学改善,凋亡率下降(P<0.05),同时caspase-3活性亦下降(P<0.05);神经元OGD后caspase-3活性升高,与凋亡率呈正相关(r=0.823,P<0.05),神经元经过亚低温和OGD后caspase-3活性与凋亡率亦呈正相关(r=0.841,P<0.05)。结论:OGD可使caspase-3的活性升高及神经元凋亡率增加。亚低温对神经元OGD的保护作用可能与其抑制caspase-3的活性有关。

AIM： To study the protective effect of mild hypothermia（31 ～32 °C） on rat hippocampal neurons against oxygen-glucose deprivation（OGD）-induced injury and its possible mechanisms.METHODS： An OGD experimental model of rat hippocampal neurons in vitro was established to simulate cerebral ischemic-hypoxic injury.The rat hippocampal neurons were randomly divided into 4 groups： control group,mild hypothermia group,OGD group and mild hypothermia ＋ OGD group.The cell morphology was observed under light and electron microscopes.The neuronal apoptosis was detected by flow cytometry.The activity of caspase-3 in the cytoplasm was measured by colorimetry.RESULTS： The neuronal injury was apparent after OGD,with a great increase in apoptotic rate（P 0.01）.Compared with OGD group,the morphology of neuronal injury in mild hypothermia ＋ OGD group was attenuated,and the neuronal apoptotic rate and the activity of caspase-3 in the cytoplasm decreased.The activity of caspase-3 in the cytoplasm increased after OGD,and was positively correlated with the neuronal apoptotic rate（r = 0.823,P 0.05）.The activity of caspase-3 in the cytoplasm also increased after mild hypothermia and OGD,and was also positively correlated with the neuronal apoptotic rate（r = 0.841,P 0.05）.CONCLUSION： OGD can increase caspase-3 activity in the neuronal cytoplasm and induce neuronal apoptosis.Restraint on caspase-3 activity in the neuronal cytoplasm may be the mechanism by which mild hypothermia protects against neuronal injury induced by OGD.