不同持续时间亚低温对缺血新生鼠脑的保护作用

目的 研究亚低温对新生大鼠缺氧缺血性脑损伤（HIBD）形成后，其保护作用的干预最短有效持续时间。方法 建立HIBD新生大鼠模型，通过HE染色、电镜、原位末端标记手段对比观察HIBD新生大鼠亚低温干预后不同时间各脑区的凋亡细胞等。结果 常温组HIBD后24小时为凋亡细胞表达高峰，亚低温组HIBD后24小时凋亡细胞数目减少，凋亡高峰延迟出现，持续时间6、15小时比3小时保护作用明显，持续6小时与15小时脑保护作用相近。结论 HIBD后31℃亚低温干预可明显抑制凋亡的表达，保护脑神经，持续时间越长保护作用越明显，超过6小时之后延长干预时间无意义。

Protective Effects on Mild Hypothermia to Brains of Noenatal Rats with Ischemia Brain Damage in Different Lasting Time.

【 Objective】 To investigate the profitable lasting time of mild hypothermia for protection against the brain of noe natal rats with hypoxic- ischemie brain damage(HIBD). 【Methods】 Apoptosis of various brain regions was observed by using HE staining eletronmicroscopy and TdT - mediated dUTP nick end labeling (Tunel) technique, in rat pups treated with mild hy pothermia after HIBD. 【Results】 HIBD rat pups had a apoptosis top 24 hours after HIBD.Mild hypothermia can protect against the brain tissue by reducing apoptosis cells 24 hours after HIBD and postponing the apoptosis top time. This effect was more obviously in mild hypothermia lasting 6 or 15 hours groups than lasting 3 hours group and there wasn' t obvious difference between lasting 6 hours group and 15 hours group. 【Conclusions】 31°C mild hypothermia be used after HIBD can protect against the neural cells by decreasing apoptosis cells and postponing apoptosis top time, the longer ,the better, but no over 6 hours.