Research for the pathogenesis of perinatal brain damage and it's protection

7日龄大鼠接受左侧颈总动脉结扎和暴露于8%氧气1h的组合。恢复期，对照组体温维持在37℃，亚低温组降温至30℃，持续24小时。组织学上，对照组右侧脑损伤较深，亚低温组基本正常。对照组大鼠脑内caspase-3活性明显增强，亚低温组大鼠脑内caspase-3活性明显降低。这些发现提示，caspase-3活性的抑制可能是低温对新生儿神经保护作用的一个干预点。在这项测试中，HI动物表现出脑干功能障碍，通过测量III-V波和I-V波的峰间潜伏期进行评估。亚低温可明显改善V波异常。与常温组相比，低温组同侧下丘的损伤程度也有所减轻，组织学评估的损伤程度与听性脑干反应结果有很好的相关性。目前的研究表明，缺血后低温可能对未成熟的脑提供有效和持久的神经功能和组织病理学保护。

Seven-day-old rats underwent a combination of left common carotid artery ligation and exposure to 8 % oxygen for 1 hour. During recovery, the body temperature was kept at 37℃ in a control group and was reduced to 30℃ for 24 hours in a hypothermia group.Histologicaly, right side of the brain was deeply damaged in control group, however in hyprothermia group it was almost normal. Intense caspase-3 activation was observed in the control brains, but this activation was significantly reduced in hypothernmia group. These findings suggest that the inhibition of caspase-3 activation may be an interventional point underlying the neuroprotective effect of hypothermia in neonate.At 3 months of age, the ABR were performed. In this test, HI animals showed brain stem dysfunction assessed by measuring interpeak latencies for waves III-V and I-V. Hypothermia significantly ameliorated wave V abnormalities. Injury to the ipsilateral inferior colliculus was also reduced in the hypothermia group compared with that in the normothermia group, and the degree of damage assessed histologicallycorrelated well with auditory brainstem response findings. The current study demonstrates that postischemic hypothermias may provide effective and long-lasting neurofunctional as well as histopathologidcal protection to the immature brain.