^(60)Co-γ射线全脑常规照射后大鼠血脑屏障的电镜观察

To study changes of blood-brain barrier with electron microscope after conventional whole brain irradiation by ^(60)Co-γ-ray

目的:观察60Co-γ射线全脑常规照射后大鼠血脑屏障(BBB)的超微结构改变。方法:20只SD大鼠随机分为5组,依次为对照组、10 Gy组、20 Gy组、30 Gy组和40 Gy组,每组4只。60Co-γ射线全脑常规照射,2 Gy.次-1,5次.周-1,照射后16 h用镧示踪电镜化学技术观察大鼠BBB超微结构的变化。结果:对照组镧颗粒局限在血管腔内;10 Gy组紧密连接处见镧颗粒沉积;20 Gy组镧颗粒弥漫性地分布于神经细胞间隙;30 Gy组镧颗粒进入神经细胞内,并分布于线粒体、内质网等细胞器表面;40 Gy组镧颗粒弥漫分布于脑组织细胞间和细胞内,可见毛细血管内皮细胞及神经细胞失去正常形态,结构破坏。结论:全脑常规外照射后大鼠BBB均出现病理改变,且射线具有降低及破坏BBB功能的作用,在全脑放疗期间随照射剂量的变化而呈规律性改变,具有可预测性。

To study uhrastructural blood-brain barrier（BBB） in rats after conventional whole brain irradiation by ^60Co-γ-ray. Methods According to different dosage of irradiation, 20 SD rats were divided into five groups at random,the control group（unirradiation）, 10 Gy group,20 Gy group,30 Gy group and 40 Gy group. Every group had 4 rats. The rats were exposed to conventional fractionation（2 Gy · d^-1 ,5 days every week） for whole brain by ^60Co-γ-ray. 16 hours after irradiation, the changes of uhrastructure of BBB were observed by lanthanum trace labeling with electron microscopy. Results The lanthanum was only circumscriptusly distributed in lumens of blood vessel in control group. The lanthanum deposited in tight junctions in 10 Gy group. Most tight junctions of endothelial cell opened which the lanthanum entered the extra cellular space but not entered into the neurons in 20 Gy group. The lanthanum through tight junctions of capillary vessel and basement membrane entered the plasma, mitochondria and endoplasmic reticulum of neurons in 30 Gy group. To the 40 Gy group, lanthanum nitrate particles diffusely existed in the brain tissue and a few endothelial cells and neurons lost normal configuration. Conclusions The BBB of rats show pathological changes after whole brain conventional irradiation. The rays have the effect of damaging the function and structure of BBB and change regularly according to the changes of irradiation doses, which have predictability.