X线照射原代培养大鼠海马神经元后p35、p25的表达及Cdk5激酶活性变化  

p35 and p25 expressions and Cdk5 kinase activity in primary cultured rat hippocampal neurons with X-ray exposure

作　　者：韩永清[1] 孙爱民[1] 刘鹊凌[1] 陈龙华[1] 袁亚维[1] 

机构地区：[1]南方医科大学南方医院放疗科,广东广州510515

出　　处：《南方医科大学学报》2009年第3期405-407,411,共4页Journal of Southern Medical University

基　　金：国家自然科学基金(30670633);广东省自然科学基金(06024386)

摘　　要：目的研究X线照射培养大鼠海马神经元后p35,p25的表达及Cdk5激酶活性变化,为放射性脑损伤的预防和治疗提供理论依据。方法30GyX射线单次照射培养至12d的海马神经元,用Western-blotting检测Cdk5的激活蛋白p35、p25的水平,用DAPI染核方法检测海马神经元凋亡情况。结果p35蛋白水平在照射后3.5和4h分别比对照组升高(1.51±0.13)、(1.45±0.14)倍,差异均有统计学意义(P<0.01);p25蛋白水平在照射后6h比对照组升高(1.62±0.28)倍,差异有统计学意义(P<0.05)。30Gy组在照射后24h核固缩百分数为(24.8±3.97)%,与对照组(1.82%±1.08%)有显著性差异(P<0.01);30Gy+roscovitine组在照射后24h核固缩百分数为(7.74±2.27)%,与对照组有显著性差异(P<0.01)。结论X线照射培养海马神经元后p35、p25蛋白表达增加,激活cdk5;应用Cdk5抑制剂roscovitine抑制Cdk5活性可以显著减少神经元的凋亡。Objective To study the expressions of p35 and p25 and Cdk5 kinase activity in cultured rats hippocampal neurons following X-ray exposure to provide experimental evidence for prevention and treatment of radiation encephalopathy. Methods The hippocampal neurons cultured for 12 days were subjected to a single-dose X-ray exposure of 30 Gy. Western blotting was used to detect the p35 and p25 protein levels, and the effect of pretreatment with roscovitine, a Cdk5 inhibitor, on the apoptosis of the hippocampal neurons following the exposure was examined with 4′,6-diamidino,2-phenylindole （DAPI） staining. Results The protein level of p35 increased significantly 3.5 and 4 h after the irradiation by 1.51 ±0.13 and 1.45±0.14 folds in comparison with the control level, respectively （P〈0.01）, and the p25 level increased significantly 6 h after irradiation by 1.62±0.28 folds （P〈0.05）. Nuclear condensation occurred in （24.8±3.97）% of the neurons 24 h after 30 Gy X-ray exposure, a rate significantly higher than that in the nonexposed cells [（1.82±1.08）%, P〈0.01） and that in roscovitine-pretreated neurons [（7.74±2.27）%, P〈0.01）. Conclusion X-ray exposure activates Cdk5 by increasing the p35 and p25 expressions in rat hippocampal neurons, and inhibition of Cdk5 activity with roscovitine can significantly protect the neurons from apoptosis.

关 键 词：P35 p25 CDK5 海马 神经元 

分 类 号：R818[医药卫生—放射医学]