瘦素对小鼠脑缺血/再灌注损伤神经元凋亡的影响

目的：研究Leptin在脑缺血性损伤神经元凋亡中的作用及其机制。方法：将75只雄性昆明小鼠完全随机分成3组，即假手术组、缺血/再灌注模型组、Leptin干预组；通过大脑中动脉栓塞（MCAO）复制小鼠局灶性脑缺血再灌注损伤模型，Leptin干预组在缺血0 min腹腔注射Leptin（1μg/g体重），TUNEL染色检测神经元凋亡，RT-PCR检测凋亡相关基因bcl-2和caspase-3 mRNA表达，免疫组化凋亡相关基因bcl-2和caspase-3蛋白水平的表达。结果：模型组脑缺血中心区神经元以坏死为主，与假手术组相比，其半影区神经元凋亡数量显著增多、促凋亡基因cas-pase-3和抑凋亡基因bcl-2的mRNA和蛋白表达水平均显著升高（P<0.01）；与模型组比较，Leptin干预组半影区凋亡神经元数量显著减少、caspase-3 mRNA和蛋白表达水平显著降低（P<0.01），抑凋亡基因bcl-2 mRNA和蛋白表达水平显著升高（P<0.01）。结论：Leptin能够通过上调抑凋亡基因bcl-2表达，下调促凋亡基因caspase-3表达抑制神经元凋亡，在脑缺血性损伤中发挥神经保护作用。

The effects of leptin on neuron apoptosis in mice with cerebral ischemia/reperfusion injury

Objective:To study the effect of leptin on neuron apoptosis in mice with cerebral ischemia injury. Methods:Seventy-five male Kuming mice were randomly divided into 3 groups:sham, model and leptin intervention group, respectively. Focal cerebral ischemia/reperfusion injury model in mice was established by middle cerebral artery occlusion. Leptin intervention group was injected with leptin (1μg/g weight, I. P.) at 0 min of ischemic injury. Neuron apoptosis was detected by TUNEL staining. The mRNA expression of apoptosis relative gene bcl-2 and caspase-3 were detected by RT-PCR. The protein expression of bcl-2 and caspase-3 were detected by immunohistochemistry. Results:In model group, most of the neurons in the central area of cerebral ischemia had necrosis obviously, and the amount of neuron apop-tosis was much higher than that in sham group (P<0.01). Compared with sham group, both expression of pro-apoptosis gene caspase-3 and anti-apoptosis gene bcl-2 increased significantly in model group (P<0.01). Compared with model group, the amount of neuron apoptosis and expression level of caspase-3 were decreased significantly (P<0.01), whereas the mRNA and protein expression of bcl-2 were increased sig-nificantly in leptin intervention group (P<0.01). Conclusion:Leptin could reduce neuron apoptosis through down-regulation the expression of caspase-3 and up-regulation the expression of bcl-2. It suggests that leptin could play a neuroprotective role in cerebral ischemia injury.