糖皮质激素加剧缺血诱导神经细胞损害的研究

Influence of glucocorticoid on ischemia-induced neuronal damage in gerbil hippocampus

目的 观察糖皮质激素对神经细胞缺血性损害的影响。方法 2 1只雄性沙士鼠随机分为 3组 ,未缺血组 (A组 ,n =7) ,缺血组 (B组 ,n =7)和实验组 (C组 ,n =7)。A和B组脑室内给予生理盐水 10 μl,而C组给与地塞米松 3μg。A组未作缺血处理 ,B组和C组 1h后阻断双侧颈总动脉 ,2 5min后恢复血流。实验过程中控制脑温度在 37 5℃± 0 2℃。 1周后将动物脑组织取出 ,做 5 μm厚的脑组织切片 ,经苏木素 -伊红染色后计数海马CA1区 1mm长度内残存的锥体细胞数。结果 (1)与A组相比 ,B组和C组残存细胞数明显减少 (P <0 0 1) ;(2 )C组的残存细胞数明显少于B组 (P <0 0 1)。结论 (1)前脑缺血 2 5min可致海马CA1区的锥体神经细胞的明显损害 ;(2 )地塞米松明显加剧缺血时的脑细胞死亡。

Objective To investigate the effect of glucocorticoid on ischemia-induced neuronal damage in gerbil hippocampus with forebrain ischemia model.Methods Twenty-one gerbils were randomly assigned to 3 groups (7 animals each). The animal was anesthetized and both common carotid arteries were exposed and separated. Silk threads were looped around these arteries. In group A and group B ,10 μl saline was given and in group C dexamethasone-water soluble ( 3μg dissolved in 10 μl saline ) was administered intracerebroventricularly. After a stabilization period of 60 min, transient forebrain ishcmia for 2.5 min was induced in group B and group C by pulling the arteries with 8g weights under the brain temperature of 37.5℃±0.2℃. Seven days after the ischemia, the brains were taken out and fixed with 10% buffered formalin. Brain slices, 5 μm thick, were stained with hematoxylin and eosin. The numbers of preserved pyramidal cells in the hippocampal CA1 field per 1 mm length of stratum pyramidal were counted.Results (1) Compared with those in group A, the preserved pyramidal cells in hippocampal CA1 field were reduced in group B and group C (P<0.01). (2) The preserved pyramidal cells in group C were fewer than those in group B (P<0.01).Conclusions Transient forebrain ischemia for 2.5 min can produce a marked damage in the hippocampal CA1 region. Glucocorticoid produce deleterious effect on ischemia-induced injury of hippocampal neurons in vivo.