放射诱导大鼠脑神经元和胶质细胞凋亡及敏感性的比较研究

目的　探讨X射线照射对大鼠脑神经元和胶质细胞凋亡的影响。方法　大白鼠分对照组及 2 ,4 ,6 ,8GyX射线照射组 ,照射后 1,2 ,4 ,6 ,12 ,2 4h分别取材进行光镜、电镜及DNA电泳观察 ,并用双标法计数凋亡的神经元数、胶质细胞数。结果　照射后鼠脑细胞系 2种细胞均产生凋亡的改变 ,胶质细胞凋亡率较神经元升高显著 (P <0 0 0 0 1) ,随着剂量的增高细胞凋亡率逐渐增多。结论　X射线能诱导鼠脑神经元和胶质细胞凋亡 ,凋亡率有剂量依赖性和时间规律性 ,其中胶质细胞最敏感。

Radiation-induced cerebral cell apoptosis in rats

Objective To study the influence of radiation on rat cerebral cells including neurons and gliocytes. Methods The rats were divided into control group and X-ray radiation groups with different doses.The apoptosis of cells at different time points after radiation was observed by optic microscopy,electron microscopy and DNA agarose gel electrophoresis.The double label method (in situ end-labeling of DNA strand breaks for labeling apoptotic cells,and immunhistochemistry for labeling cell type ) was used to label apoptotic neurons and gliocytes cells separately. Results The distinct morphological features of apoptosis and the DNA fragmentation ladders on agarose gel electrophoresis were seen in radiation groups.The rate of apoptosis in the adult rat brain was low.There were many apoptotic glial cells (about 93%) and a few apoptotic neurons (about 5%) after radiation.The apoptotic rate in high dose group was higher than that in low dose group. Conclusion Apoptosis can be induced by radiation in rat brain,the apoptotic rate increases with a increasing dose in the range of 2-8 Gy.The gliocytes are more sensitive to radiation-induced apoptosis than the neurons.