新生大鼠脑缺氧缺血对脑组织谷氨酸及环核苷酸的影响

Alterations of glutamate and cyclic nucleotides in neonatal rat brain after cerebral hypoxic-ischemic injury

目的 研究新生大鼠缺氧缺血性脑损伤 (HIBD)时谷氨酸 (Glu)和环核苷酸 (cAMP和cGMP)的代谢改变及意义。方法 选 7日龄Wistar新生大鼠 ,随机分为对照组和缺氧缺血组。采取结扎左侧颈总动脉并吸入低氧的混合气体制作HIBD动物模型。用氨基酸自动分析仪与放免法测定不同时间脑组织Glu、cAMP和cGMP含量。结果 脑缺氧缺血后即刻Glu(17.5 6± 5 .32mol/g P <0 .0 1)和cAMP(15 .0 1± 3.80nmol/g P<0 .0 5 )较对照组显著升高 ,随后逐渐下降 ,于 6 0～ 180min降至正常 ,cGMP则显著升高 (0 .88± 0 .19nmol/ g P <0 .0 5 )。结论 新生大鼠HIBD时脑组织Glu、cAMP、cGMP含量发生变化 。

Objective To study the changes and roles of glutamate(Glu) content and cyclic nucleotide levels in neonatal rat brain after hypoxic ischemic brain damage(HIBD).Methods Neonatal Wistar rats of 7 days were divided into two groups randomly, namely control group and cerebral hypoxic ischemic group. The models of perinatal hypoxic ischemic brain injury rats were prepared by ligation of left common carotid artery combined with a temporary systemic hypoxia (inhaling 8 % O 2 and 92 % N 2). The changes of Glu concentration and cyclic nucleotide levels in neonatal rat brain were observed by microdetermination or immunoradioassay at different times after injury.Results The content of Glu increased significantly as (17.56±5.32) mol/g(P<0.01), and levels of cAMP increased distinctly as (15.01±3.80) nmol/g(P<0.05) at 0 minute after HIBD as compared with control group, and then declined gradually and reached their normal levels between 60 and 180 minutes after HIBD. Levels of cGMP increased distinctly as (0.88± 0.19) nmol/g at 180 minutes after HIBD(P<0.05).Conclusions There are changes of Glu content and levels of cAMP and cGMP in neonatal rat brain after HIBD, which induce excitotoxicity and metabolic stress and play important roles in aggravation of brain damages.