电离辐射致小鼠海马神经细胞凋亡及p53与PUMA表达改变

Apoptosis,p53 and PUMA protein expression changes in hippocampus after whole-brain exposure to ionizing radiation in adult mice

目的研究电离辐射对小鼠海马神经细胞凋亡及p53、p53 up-regulated modulator of apoptosis(PUMA)蛋白表达的变化。方法 60只ICR小鼠随机分为0.4、4、10和18 Gy 4个照射剂量组及对照组。处理后在4 h时间点取小鼠全脑,原位末端标记(TUNEL)法检测海马神经细胞凋亡;蛋白免疫印迹(Western blot)法检测海马组织中p53与PUMA蛋白的表达情况。结果 TUNEL结果显示细胞凋亡率随照射剂量增加而增加;Western blot结果显示X射线照射后4 h点p53、PUMA表达随剂量增高而增加,二者的表达呈平行状态。结论在本试验条件下,电离辐射致小鼠海马神经细胞出现不同程度的凋亡并呈现剂量-效应关系;小鼠海马组织中p53和PUMA蛋白表达有明显的剂量依赖性,且和细胞凋亡的改变有一定关联。

Objective To study the effect of ionizing radiation on neuronal apoptosis and expressions of p53 and p53 upregulated modulator of apoptosis（PUMA） protein in hippocampus of adult mice.Methods 60 adult ICR mice were randomly divided into five groups including four X-ray treatment groups and one control group.Mice in treatment groups were treated by different doses（0.4 Gy,4 Gy,10 Gy and 18 Gy） X-ray whole-brain irradiation one time.Whole brains of the mice in both of treatment groups and control group were gotten at 4 hour（h） point after irradiation.TdT-mediated dUTP nick end labeling（TUNEL） assay was used to detect of hippocampal neuron apoptosis.Taking advantage of Western blot,the expression of p53 and PUMA protein in hippocampus were analyzed.Results In general,ratio of apoptosis was increased along with X-ray dose increased.Western blot results showed that the expressions of p53 and PUMA protein gradually raised along with X-ray dose increase.Conclusion X-ray could induce apoptosis in hippocampal CA1 area neurons of mice,with a dose-effect relationship.The expressions of p53 and PUMA protein in hippocampus of adult mice showed obvious dose-dependence,and apoptosis of hippocampus neuron after irradiation was changed following with p53 and PUMA protein expressions.