新生鼠缺氧缺血脑损伤脑细胞凋亡与钙超载的研究

目的　研究在新生大鼠缺氧缺血性脑损伤时脑细胞凋亡的规律；探讨细胞凋亡与钙超载的关系及钙离子通道拮抗剂对细胞凋亡的干预作用。方法　用流式细胞仪测定缺氧缺血（HI）后1h～10d内不同时间点脑细胞凋亡比例，并通过激光共聚焦扫描显微镜，观察硫酸镁和川芎嗪对由谷氨酸刺激造成的神经元细胞内Ca

The pattern of brain cells apoptosis, the relationship to Ca2+ overload and the drug intervention in newborn rats with hypoxic-ischemia

Objective　To explore the pattern of brain cells apoptosis in newborn rats after hypoxic-ischemia (HI), the relation to Ca2+ overload, and the effect of calcium channel antagonist on apoptosis.Methods The percentage of neuronal apoptosis was measured after 1 hour to 10 days of HI with the flow cytometry. The antagonism of MgSO4 and ligustrazin to the intracellular Ca2+ overload stimulated by the glutamate in the brain slice and neuron was also observed by laser confocal scanning microscopy (LCSM) in vitro. The newborn rats were randomly divided into 4 groups, normal control, HI group, HI with MgSO4 group and HI with ligustrazin group, respectively. Results　The apoptosis in neuron was observed in normal newborn rats of 7 days (12±7)%. The increase of apoptosis began after 12 hours of HI (20±7)%. After 5 days of HI, the percentage of apoptosis cells reached a peak level (69±10)%, which showed significantly differences from the percentage of apoptosis 72 hours and 7 days after HI(P＜0.01). The percentage of apoptosis decreased to (33±12)% 10 days after HI. Both MgSO4 and ligustrazin showed a positive effect on relieving Ca2+ overload induced by glutamate in vitro. The administration of both drugs after HI could effectively prohibit apoptosis, which decreased to 26.7% and 26.2%, respectively (F=18.86, q=4.34 and 4.25, P＜0.01 and ＜0.05).Conclusion　The best time of the treatment of HI might be 5 days after HI, because the peak level of apoptosis showed at the 5th day after HI in the experiment. The calcium channel antagonist MgSO4 and ligustrazin could reduce the neuron Ca2+overload, and therefore prohibit the apoptosis and protect brains from the HI damage.