电磁辐射对原代大鼠皮层神经元细胞周期素依赖性蛋白激酶5及其活化亚基的影响

Electromagnetic irradiation enhances CDK5 and its activators in primary cultured rat cortical neurons

目的研究电磁辐射对原代培养大鼠皮层神经元细胞周期素依赖性蛋白激酶5(cyclindependent kinase 5,CDK5)及其活化亚基的影响。方法采用峰值功率密度为90W/cm2的电磁波辐照原代培养大鼠皮层神经元10min,采用逆转录-聚合酶链反应(RT-PCR)法观察原代培养大鼠皮层神经元CDK5 mRNA含量的变化;采用Western blot法观察原代培养大鼠皮层神经元CDK5及其活化亚基P35、P25蛋白含量的变化;采用液体闪烁计数法检测原代培养大鼠皮层神经元CDK5活性的变化。结果 90W/cm2电磁波辐照10min后,原代培养大鼠皮层神经元CDK5 mRNA及蛋白含量在各个时相点未有明显改变(P>0.05),CDK5活性在电磁辐射辐照后3、6h显著升高(分别较假辐照组增高约97%、51%,P<0.05),其活化亚基P35蛋白含量无显著改变(P>0.05),但其活化亚基P25蛋白含量在电磁辐射辐照后0、3、6h明显上调(分别较假辐照组增高约25%、46%、24%,P<0.05)。结论电磁辐射可引起原代大鼠皮层神经元P25蛋白含量及CDK5活性明显升高,并可能是电磁辐射所致神经元损伤的机制之一。

Objective To investigate the effect of electromagnetic irradiation on cyclin dependent kinase 5 （CDK5） and its activators in primary cultured rat cortical neurons. Methods Rat cortical neurons were isolated and then primary cultured from neoborn rats. Then the cells were exposed to the electromagnetic wave （peak power 90 W/cm2） for 10 min. The mRNA level of CDK5 was determined by RT-PCR and the protein levels of CDK5 and its activator P35 and P25 were determined by Western blotting in 0, 3, 6, 12 and 24 h after exposure. The activity of CDK5 was quantified by liquid scintillation counting. Results There was no significant change in either mRNA or protein level of CDK5 in primary cultured cortical neurons after electromagnetic exposure at any time points （P0.05）. The activity of CDK5 in primary cultured cortical neurons was increased significantly by 97% at 3 h and by 51% at 6 h after exposure （P0.05）. Meanwhile, after the exposure, the protein level of P35 was not significantly changed （P0.05）, but that of P25 was significantly increased by 25% at 0 h, by 46% at 3 h and by 24% at 6 h （P0.05）. Conclusion The electromagnetic irradiation induces significant increase of P25 protein level and CDK5 activity in primary cultured cortical neurons, indicating that P25/CDK5 may be involved in the process of the electromagnetic irradiation-induced neuron damage.