不同发育期大鼠海马N-甲基-D-天冬氨酸受体3A亚基的表达及其抗缺血缺氧能力

Developmental expression of N-methyl-D-aspartate receptor 3A protein on rat hippocampus and the relationship to anti-hypoxia and anti-ischemia ability

目的观察不同发育时期海马神经元N-甲基-D-天冬氨酸(NMDA)受体3A亚基(NR3A)的表达及其抗缺血缺氧能力与其NR3A表达量的关系。方法取鼠龄1,5,10,15,20,30和90 d大鼠海马,采用Western印迹法检测海马神经元NR3A表达;制备鼠龄10,15,20和30 d大鼠海马切片,免疫组化法检测NR3A表达。取鼠龄10,15,20和30 d海马脑片,体外制备氧糖剥夺损伤模型(OGD),采用PI染料标记和荧光方法检测观察神经元坏死情况。结果 Western印迹和免疫组化结果显示,大鼠海马NR3A亚基的表达以10 d鼠龄时最高,此后逐渐下降,直至成年都一直维持较低的水平。对海马脑片进行OGD处理后,鼠龄10 d的海马脑片受损细胞数明显少于其他组,5 d,20 d组PI阳性细胞数多于10 d,鼠龄30 d的海马脑片损伤细胞数最多。结论 鼠出生后海马神经元NR3A亚基表达呈现先高后低的状态,成年鼠NR3A亚基的表达量维持在较低水平。NR3A亚基的高表达有利于神经元对抗OGD造成的损伤。

OBJECTIVE To analyze developmental expression of N-methyl-D-aspartate receptor（NMDAR） 3A （NR3A） protein on rat hippocampi and explore whether the anti-hypoxia and anti-ischemia ability is related to the expression level of NR3A protein. METHODS Analyze NR3A protein expression on hippocampi from rat aging 1,5, 10, 15, 20, 30 d by Western blotting. Use hippocampal sections from rat aging 5, 10, 20, 30 d to analyze NR3A expression pattern by immunocytochemistry. Nonviable cells in hippocampal slices from 5, 10, 20, 30 d-old rats after oxygen and glucose deprivation （OGD） were labeled with propidium iodide. RESULTS Western blotting and immunocytochemistry results showed that the expression of NR3A protein on rat hippo- campus began to increase on the postnatal days. It reached the highest expression level on post natal day 10 （10 d） , and decreased gradually, which remained low into the adulthood. Neurons were damaged after OGD exposure. The amount of injured neurons on hippocampal slices from rats aging 10 d was obviously lower than other groups. More dead neurons showed on slices from rats aging 5 d and 20 d. Damaging conditions was most serious on slices from rat aging 30 d. CONCLUSION The protein expression of NR3A on rat hippocampus increases on post natal days, and decreases after 10 d, which remains low into adulthood. The protective capability against ischemic injury is positively related to the expression level of NR3A on rat hippocampus.