皮质酮对原代培养海马神经元的毒性作用及NMDA受体亚基表达的改变

目的研究皮质酮对大鼠海马神经元的毒性作用及NMDA受体亚基表达的影响.方法以体外原代培养的大鼠海马神经元为研究对象,根据影响因素,即给予的不同浓度皮质酮和其它因素分为8个组:对照组、10-7mol/L皮质酮组(简称10-7组)、10-6mol/L皮质酮组(简称10-6组)、10-5mol/L皮质酮组(简称10-5组)、10-6 高糖组、10-5 高糖组、10-6mol/L MK801组和10-5mol/L MK801组,镜下观察不同浓度皮质酮作用下海马神经元形态学的变化,并采用MTT方法测量各组细胞存活率,利用免疫细胞化学结合图象分析对原代培养海马神经元NMDA受体亚基的表达进行观察.结果 10-6、10-5浓度的皮质酮对海马神经元影响较大,细胞存活率较对照组明显降低,但10-6 高糖组、 10-5mol/L 高糖组、10-6mol/L MK801及10-5mol/L MK801 4个组,分别与相同皮质酮浓度处理组比较,细胞存活率显著提高.10-6和10-5组海马神经元上NMDA受体亚基表达较对照组明显降低.10-7mol/L浓度的皮质酮对上述指标影响不大.结论过量的皮质酮对大鼠海马神经元具有损伤作用,NMDA受体参与了此过程,NMDA受体拮抗剂和高浓度葡萄糖可保护海马神经元.

NEUROTOXIC EFFECT OF CORTICOSTERONE ON PRIMARY CULTURED HIPPOCAMPAL NEURONS AND THE CHANGE OF NMDA RECEPTOR SUBUNITS EXPRESSION

Objective To study the effect of corticosterone (CORT) on the hippocampal neurons and the expression of NMDA receptor subunits. Methods According to the different treatments, the rats were divided into 8 groups: control group,10 -7 mol/L CORT group(10 -7 group),10 -6 mol/L CORT group(10 -6 group),10 -5 group mol/L CORT group(10 -5 group),10 -6 +high glucose group,10 -5 +high glucose group,10 -6 +MK801 group and 10 -5 +MK801 group. MTT assay detected the survival rate of the cells. The expression of NMDA receptor subunits in cultured primary hippocampal neurons was observed by using immunocytochemistry combined with image analysis. Results The results showed that 10 -6 and 10 -5 mol/L of CORT had a great effect on the morphology of hippocampal neurons. Compared with that of the control group, the survival rate of neurons was significantly decreased in 10 -5 and 10 -6 groups. But in 10 -6 +high glucose, 10 -5 +high glucose, 10 -6 +MK-801 and 10 -5 +MK-801 groups, the rate was significantly increased in comparison with that of the corresponding CORT-treated groups. At the same time, the expression of NR1, NR2A and NR2B was down regulated in 10 -5 and 10 -6 groups. Conclusion Excessive corticorsterone can damage primary cultured hippocampal neurons, and NMDA receptors are involved in this neurotoxic effect. High glucose and NMDA receptor antagonists can protect the hippocampal neurons from this neurotoxicity.