低体积分数氧预处理对缺氧缺血性脑损伤新生大鼠海马区脑红蛋白变化的影响

Effect of Hypoxia Preconditioning on Change of Neuroglobin in Neonatal Rat with Hypoxia-Ischemia Brain Damage

目的观察低体积分数氧(低氧)预处理对缺氧缺血性脑损伤(HIBD)新生大鼠脑红蛋白(NGB)变化的影响,探讨低氧预处理与NGB的关系。方法随机将出生7 d Wistar大鼠110只分为3组:假手术组(n=10)、HIBD组(n=50)、低氧预处理后HIBD组(n=50),HIBD组和低氧预处理后HIBD组在模型建立后1、5、15、30和60 min各个时间点再分为5个亚组。采用双侧颈总动脉结扎的方法建立HIBD模型,应用反转录-聚合酶链反应(RT-PCR)和免疫组织化学方法检测在低氧预处理干预下脑缺氧缺血后NGB mRNA及蛋白质在不同时间的表达量。结果RT-PCR半定量分析:HIBD组NGB mRNA在1、5 min时相对表达量均显著高于假手术组(Pa<0.05);15、30和60 min表达下降,与假手术组比较无统计学意义(Pa>0.05)。与HIBD组比较,低氧预处理后HIBD组1、5 min NGB mRNA相对表达量增加,15、30和60 min下降,但差异均无统计学意义(Pa>0.05)。免疫组织化学结果显示低氧预处理后HIBD组海马区域NGB在1、5、15、30和60 min平均吸光度(195.0±11.26,202.41±12.20,182.60±15.72,178.22±14.37,164.86±28.99)与HIBD组(195.59±11.59,201.40±13.61,178.09±18.92,173.75±14.30,163.45±18.66)比较无统计学意义(Pa>0.05)。结论低氧预处理对新生大鼠的脑保护作用可能与NGB的变化关系不大。

Objective To observe the effect of hypoxia preconditioning （ HPC ） on the change of ueuroglobin （ NGB ） in neonatal rats with hypoxia - ischemia brain damage （HIBD）. Methods One hundred and ten 7 - day - old wistar rats were randomly divided into 3 groups：sham operation group （n = 10） , hypoxie -isehemie brain damage （HIBD） group （n = 50） and hypoxic -isehemic brain damage after HPC group （ n = 50）. The rats in HIBD group and HIBD after HPC group were further divided into 5 subgroups respectively based on 1, 5,15,30,60 minutes after the model was set up. The neonatal rats of carotid artery ligation was used as the research model. Preconditioning was performed 24 hours before hypoxie - ischemie by placing rats in the hypoxic chamber for 3 hours. The brain tissues were taken from the rats at 1,5,15.30 and 60 min respectively after the models were made in HIBD group and HIBD after HPC group. The expressions of NGB of brain tissues were studied at 1,5,15, 30 and 60 min after HIBD using immunohistochemistry and semiquantitative reverse transcription -polymerase chain reaction （ RT - PCR）, respectively. Results RT - PCR analysis showed that the relative expressions of NGB in brain tissue at 1 rain and 5 rain in HIBD group were significantly higher than those in the sham operation group （ Pa 〈 0.05 ） respectively, but there were no significant differences at 15 rain,30 rain and 60 min between HIBD group and sham operation group （P 〉 0.05 ）, and there were no significant differences between the HPC group and the HIBD group （ P 〉 0.05 ）. The result of immunohistochemistry showed that there were no significant differences of the level of NGB in HIBD after HPC group （ 195.0 ± 11.26,202.41 ± 12.20,182.60 ± 15.72,178.22 ± 14.37,164.86 ± 28.99） and HIBD group（ 195. 59 ± 11. 59 ,201. 40±13. 61,178. 09 ±18. 92 ,173. 75 ±14. 30,163. 45 ±18. 66 ） （ P 〉0.05）.Conclusions HPC has orotective effect on neonatal rats with cerebral hypoxia-ischemia, but it does not have obvious effect on NGR.