目的:探讨单唾液酸神经节苷脂(GM1)对体外循环大鼠海马神经元凋亡的影响及机制.方法:18只健康成年雄性SD大鼠,随机分为3组:正常对照组、CPB组和GM1组.经右颈静脉插管引流,右颈动脉插管灌注建立CPB,转流时间60 min,建立CPB动物模型.CPB后3h时处死大鼠,4％多聚甲醛灌注固定后取左侧大脑组织,利用TUNEL法观察海马神经元凋亡,免疫组化法检测海马神经元Caspase-3蛋白表达,并用电子显微镜观察神经元超微结构变化.结果:与正常组比较,GM1组和CPB组海马神经元凋亡细胞平均积分光密度(IA)、Caspase-3蛋白表达均增强(P＜0.01).GM1组海马神经元凋亡细胞平均积分光密度(IA)为8.94±0.42,与CPB组(14.87±0.70)相比明显降低(P＜0.01);GMI组海马Caspase-3阳性神经细胞平均积分光密度比CPB组降低了38.84 ％(P＜0.01).电镜下CPB组海马可见异染色质明显边集、凝聚,线粒体嵴减少或空泡变性,细胞器消失等不可逆性的损伤改变；GM1组神经元细胞核圆形,线粒体嵴少量减少,细胞器仍可见.结论:单唾液酸神经节苷脂对体外循环大鼠海马神经元凋亡具有明显的抑制作用,其机制与抑制Caspase-3的表达有关.%Objective: To investigate the effect of monosialoganglioside 1 (GM1) on the neuronal apoptosis of the hippocampus after cardiopulmonary bypass (CPB) in rats. Methods: Eighteen healthy adult male SD rats were randomly divided into 3 groups; control group, CPB group and GM1 group. Blood was drained from the right atrium via jugular vein multiorificed catheter into the CPB circuit and return to the right carotid artery. Sixty minutes cardiopuhnonary bypass was performed on the rat. 3 h after CPB 4% polymerized formaldehyde was injected via the right carotid artery. The left brains were immediately removed. Caspase-3 positive neurons were detected by irnmunohistochemistry and neuronal apoptosis was observed with TUNEL. Ultrastructural changes were examined by electron microscope. Results: (1) Compared with that in the control group, Caspase-3 positive neurons and the integrated OD average of hippocampus apoptosis were significantly higher in CPB group and GM1 group. The integrated OD average of hippocampus apoptosis in GMlgroup was 8.94± 0.42, and which was significantly lower (P<0.01) compared with that in CPB group (14.87±0.70). The number of Caspase-3 positive neurons in GM1 group was 38.84 % which was less than that in CPB group (P<0.01). (2) Electron microscopy showed that there were heterochromatin marginating, vacuolar degeneration or cristae disappearing of mitochondria, cell organelles disappearing in CPB group and in GM1 group there were round nucleus, a little disappeared cristae of mitochondria and organelles were still visible. Conclusion: Monosialoganglioside 1 efficiently inhibited the neuronal apoptosis of hippocampus after cardiopuhnonary bypass in rats, and inhibited expression of Caspase-3 in apoptosis.
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