新生大鼠缺氧缺血性脑损伤氧化还原因子-1蛋白表达及意义的研究

Expression of redoxfactor-1 protein in the cerebral tissues of neonatal rats after brain hypoxia-ischemia

摘要:

目的：探讨新生大鼠缺氧缺血性脑损伤(HIBD)后,氧化还原因子-1 (APE/Ref 1)蛋白在大脑皮质不同时相的表达及其与神经细胞凋亡的关系。方法：将新生7日龄SD大鼠制成HIBD动物模型,采用免疫组织化学方法及原位缺口末端标记(TUNEL)法分别观察正常对照组、假手术组及缺氧缺血1, 3, 6, 12, 24, 48hAPE/Ref 1蛋白及神经细胞凋亡变化。结果：APE/Ref 1蛋白在正常对照组、假手术组神经细胞核内广泛表达,两组间差异无显著性(P>0. 05);而缺氧缺血组大脑皮质该蛋白表达随缺血时间的延长而下降,且各时间点间差异显著(P<0. 05)。大脑皮质凋亡阳性细胞表达与APE/Ref 1相反,其随缺血时间的延长逐渐增多,并在24h达到高峰,均高于正常对照组及假手术组(P<0. 05)。结论：新生大鼠脑组织缺氧缺血后,大脑皮质神经元APE/Ref 1蛋白表达减少, 凋亡细胞表达增加,提示APE/Ref 1蛋白减少和DNA修复功能失败可能与脑缺氧缺血后神经细胞的凋亡发生有关。

Abstract:

OBJECTIVE: It was aimed to study the expression of redoxfactor-1 (APE/Ref-1) protein in the cerebral tissues of neonatal rats after hypoxic-ischemic brain damage (HIBD) and its relationship to apoptosis. METHODS: Seven-day-old neonatal rats were randomly assigned into a Normal control group, a Sham-operation group and a Hypoxic-ischemic (HI) group. The HIBD model was established through the ligation of left common carotid artery along with hypoxic exposure. The expression of APE/Ref-1 protein and apoptosis were determined by immunohistochemistry and terminal deoxynucleotidyl transferase mediated dUTP-biotin nick end labeling (TUNEL) staining at 1, 3, 6, 12, 24 and 48 hrs after HI. RESULTS: Immunohistochemistry results showed extensive nuclear expressions of APE/Ref-1 in the Normal control and Sham-operation groups, and there was no significant difference between the two groups. In the HI group, the nuclear expression of APE/Ref-1 protein decreased significantly with the HI time. The APE/Ref-1 protein expression in the cerebral cortex was significantly different at different HI time points. In contrast, apoptotic cells increased with the HI time and reached a peak 24 hrs after HI. Significant differences were observed in both the APE/Ref-1 protein expression and the number of apoptotic cells between the HI group and the Normal group as well as the Sham-operation group. CONCLUSIONS: The results suggested that the reduction of APE/Ref-1 protein and the failure of DNA repairing might have contributed to apoptosis after cerebral hypoxia and ischemia.