A2AR敲除对新生小鼠HIBD细胞凋亡和凋亡诱导因子表达的影响

Effect of A2AR knockout on expressions of nerve cell apoptosis and apoptosis inducing factor in newborn mice with hypoxia-ischemia brain damage

目的研究敲除腺苷A2AR对新生小鼠HIBD大脑皮层、海马CA1区AIF和TUNEL阳性细胞表达的变化。方法将A2AR基因敲除(KO)小鼠40只及同窝野生型(WT)小鼠40只分为KO组和WT组,每组下设假手术组和HIBD组,后者分1 d、3 d、7 d共3个时间点,参照经典Rice-Vannucci法建立7日龄新生小鼠HIBD模型。采用3种发育反射(翻正、趋地和悬崖逃避)对小鼠进行短期神经功能评定,TUNEL染色法观察阻断A2AR对新生小鼠HIBD后神经细胞凋亡的影响,免疫组化检测皮层和海马CA1区AIF的表达。结果 A2AR敲除能显著加重神经功能缺损和脑组织病理损伤;TUNEL染色示野生型模型组(1 d、3 d)凋亡细胞明显少于敲除型模型组(P<0.01);HIBD后AIF迅速增加,于造模后1 d达高峰;敲除型模型组均多于野生型模型组(P<0.05)。结论腺苷A2AR敲除可增加脑缺血缺氧小鼠海马皮层和CA1区的神经细胞凋亡和AIF表达,提示A2AR对新生小鼠缺氧缺血性脑损伤起保护作用。

Objective To study the expression of adenosine A2AR in AIF and TUNEL positive cells of neonatal mouse hypoxia-ischemia brain damage(HIBD) cerebral cortex and hippocampal CA1 region. Methods Forty A2AR knockout(KO) mice and forty littermate wild type(WT) mice were divided into KO group and WT group. Each group was divided into sham operation group and HIBD group. The latter was divided at 1 d, 3 d, 7 d, and a 7-day-old newborn mouse HIBD model was established with reference to the classic Rice-Vannucci method. The mice were evaluated for short-term neurological function by three kinds of developmental reflexes(retroversion, tropism and cliff evasion). TUNEL staining was used to observe the effect of blocking A2AR on neuronal apoptosis after HIBD in neonatal mice. Immunohistochemistry was used to detect cortex and Expression of AIF in hippocampal CA1 region. Results A2AR knockout significantly aggravated neurological deficits and brain tissue pathological damage;TUNEL staining showed that the apoptotic cells in the wild-type model group(1 d, 3 d) were significantly less than the knockout model group(P<0.01);AIF increased rapidly after HIBD. The peak was reached 1 day after modeling;the knockout model group was more than the wild type model group(P<0.05). Conclusion A2AR KO could obviously increase the nerve cell apoptosis caused by HIBD in the brain cortex and hippocampus CA1 of newborn mice, which suggests that A2AR have protective effects against HIBD.