摘要
实验模型采用麻醉大鼠人工吸入１０．５％—１１．０％氮氧混合气体（相当于５０００ｍ海拔高度），于低氧前５ｍｉｎ由股静脉注入α－苯基－Ｎ－叔了基甲亚胺－Ｎ－氧化物（ＰＢＮ，α－ｐｈｅｎｙｌ－ｔｅｒ－ｂｕｔｙｌｎｉｔｒｏｎｅ）。结果发现低氧１５ｍｉｎ后，皮层和海马ＰＢＮ－自旋加合物电子自旋共振（ＥＳＲ，ｅｌｅｃｔｒｏｎｓｐｉｎｒｅｓｏｎａｎｃｅ）信号强度显著大于常氧对照组（ｎ＝５，Ｐ＜０．０１）。第三组鼠于低氧前２０ｍｉｎ由股静脉注入单甲氧基聚乙二醇－超氧化物歧化酶（ＭＰＥＧ－ＳＯＤ，ｍｏｎｏｍｅｔｈｏｘｙｐｏｌｙｅｔｈｌｅｎｅｇｌｙｃｏｌ－ｓｕｐｅｒｏｘｉｄｅｄｉｓｍｕｔａｓｅ），低氧１５ｍｉｎ，皮层和海马ＰＢＮ－自旋加合物ＥＳＲ信号强度无明显下降（与低氧组比，ｎ＝５，Ｐ＞０．０５），原因之一，可能是由于ＭＰＥＧ－ＳＯＤ分子量大不能透过血脑屏障所致。另取三组鼠，一组为常氧对照组，其余两组低氧１５ｍｉｎ，分别测定了超氧化物歧化酶（ＳＯＤ，ｓｕｐｅｒｏｘｉｄｅｄｉｓｍｕｔａｓｅ，ＥＣ１．１５．１．１）、谷胱甘肽过氧化物酶（ＧＳＨ－Ｐｘ，ｇｌｕｔａｔｈｉｏｎｅｐｅｒｏｘｉｄａｓｅ，ＥＣ１．１１．１．９）抗氧化酶活力的?
Anesthetized rats were ventilated artifically to 10. 5 % 11. 0% O2 in N2 (equivalent to altitude about 5 000 m). PBN (α-phenyl-ter-butylnitrone) was injected intravenously 5 min before hypoxia. The experiment results showed that the ESR (electron spin resonance) signal intensity of PBN-spin adduct in cortex and hippocampus both increased significantly during hypoxia(15 min) as compared with normoxia group (n=5, P<0. 01). In the third group of rats injected with MPEG-SOD (monomethoxypolyethylene glycol-superoxide dismutase) intravenously 20 min before hypoxia, the ESR signal intensity of PBN-spin adduct in cortex and hippocampus did not decrease significantly under hypoxia for 15 min (compared with hypoxia group, n=5, P>0. 05). This may be due to the fact that MPEG-SOD could not pass the blood-brain barrier owing to its large molecular weight. The enzyme activity of SOD (superoxide dismutase. EC1. 15. 1. 1), GSH-Px (Glutathione peroxidase, EC1. 11. 1. 9) and content of MDA (malondialdehyde) was also determined. The results showed that the hypoxia had no effect on the SOD, GSH-Px activity and MDA content (n=7 or n=8, P> 0. 05). The above results suggested that ventilation to 10. 5%=11. 0% O2 in N2 15 min induced free radical generation in rats cortex and hippocampus, but this generation was not due to decrease of SOD,GSH-Px activity in cortex and hippocampus.
出处
《生理学报》
CAS
CSCD
北大核心
1995年第5期510-514,共5页
Acta Physiologica Sinica
基金
中国科学院上海生理研究所低氧生理开放室资助
关键词
低氧
自由基
皮层
海马
free radicals
cortex
hippocampus
hypoxia
α-phenyl-ter butylnitrone
