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目的 探讨新生鼠脑缺氧缺血再灌注后的神经保护机制。方法7d龄SD新生鼠7窝(每窝选用8只,共56只),随机分为假手术对照组、缺氧缺血脑损伤组。经弹性管穿线阻断右颈总动脉3h,低氧(8％O_2和92％N_2混合气)1h,制备HIBD模型。3h后剪开扎线予再灌注,彩色多普勒监测右侧颈总动脉血流。免疫组化检测磷酸化的CREB和c-fos在不同时间点(再灌注3h,6h,12h,24h,48h,72h和7d及假手术后24h)海马区的表达。Thionin染色观测神经元凋亡情况。结果 HIBD再灌注3h,24h新生鼠右侧海马p-CREB表达达高峰,7d后下降至假手术组水平;c-fos表达6h达高峰,24h稍降,48h又升高,7d后显著降低但仍高于对照组(P< 0.01)。Thionin染色发现:再灌注24h右侧海马CA1区已有明显的凋亡,但7d后神经元无明显丢失。结论 缺氧缺血再灌注后CREB磷酸化可能经信号转导调节c-fos的表达,这对保护损伤侧海马锥体神经元,尤其是敏感的CA1区神经元是非常重要的。 [中国当代儿科杂志,2003,5(1):12—16]
Objective To investigate the neuroprotective mechanism after cerebral ischemia-reperfusion in neonatal rats. Methods Seven SD neonatal 7-day-old mice were randomly divided into sham operation control group and hypoxic-ischemic brain injury group. HIBD model was prepared by threading the right common carotid artery for 3 h and hypoxia (8% O 2 and 92% N 2 mixture) for 1 h. After 3h cut open the nodal line for reperfusion, color Doppler monitoring right common carotid artery blood flow. Immunohistochemistry was used to detect the expression of phosphorylated CREB and c-fos in hippocampus at different time points (3h, 6h, 12h, 24h, 48h, 72h and 7d after reperfusion and 24h after reperfusion). Thionin staining observed neuronal apoptosis. Results The expression of p-CREB in the right hippocampus reached a peak at 3h and 24h after HIBD reperfusion, and dropped to the level of sham-operation group on the 7th day after reperfusion. The expression of c-fos peaked at 6h, decreased slightly at 24h and then increased at 48h, Still higher than the control group (P <0.01). Thionin staining showed that there was obvious apoptosis in hippocampal CA1 region right after reperfusion 24h, but there was no obvious loss of neurons after 7 days. Conclusions Phosphorylation of CREB may regulate the expression of c-fos by signal transduction after hypoxic-ischemia and reperfusion, which is very important for the protection of pyramidal neurons in the injured side, especially the neurons in CA1 area. [Chinese Journal of Contemporary Pediatrics, 2003,5 (1): 12-16]