伽玛刀照射猫脑组织后局部超微结构的变化

目的：研究伽玛刀引起正常脑组织微结构的变化。方法：选择１２只家猫，分成６组，５个实验组分别给予３０Ｇｙ，４０Ｇｙ，５０Ｇｙ，１００Ｇｙ和１６０Ｇｙ的剂量照射猫脑皮层。照射后４８小时观察其局部超微结构的变化。结果：１６０Ｇｙ组，神经元全部或部分空泡化；毛细血管内皮受损，管周形成大的空泡。１００Ｇｙ组，神经元胞核有空泡化，核膜完整，部分胞浆消失。５０Ｇｙ组，线粒体肿胀内质网扩张。４０Ｇｙ组，小神经元染色质凝聚，线粒体和内质网有空化。３０Ｇｙ组，只见部分内质网扩张。结论：高剂量（１６０Ｇｙ，１００Ｇｙ）可直接引起神经细胞核和细胞器损伤，低剂量主要引起细胞器和微血管损伤。细胞核比胞浆内膜性结构对射线有较高的耐受性。

UItrastructural changes of cat brain tissue irradiated with gamma knife

Purpose:UItrastructural changes of normal brain tissue irradiated with gamma knife(GK)were investigated.Methods:Twelve cats were divided into 6 group(n=2).The treatment groups were given maximal doses of 30,40,50,100,160 Gy respectively,and occipital lobes of the cat brain were irradiated with 4 mm collimator of GK.The electron microscopic studies were performed at about 48 hours after GK treatment.Results:(1)Partially or completely devoid of cytoplasmic components of the neurons were visible in cats irradiated with 160 Gy.Lots of big perimicrovascular vacuoles were found.Besides,there were some vacuolar area difficult to discern the structure.(2)Cats with 100 Gy:There were vacuoles in the nuclei of neurons with intact membrane of the nucleus and some parts of cytoplasm devoid of structure.(3)Cats with 50 Gy:The changes of the neuron nuclei were not obvious,but mitochondria and endoplasmic reticulum(ER) becomed swelling.(4)Condensation of chromatin,and swelling of ER and mitochondria were found in some small neurons in cats irradiated with 40Gy.(5)Only some ER showed swelling in cat irradiated with 30 Gy.Conclusion:(1)High doses(160,100Gy) of GK radiation directly resulted in thd damage of nuclei and cytoplasm of the neurons .(2) Low doses(50 to 30 Gy)mainly induced the damage of mitochondria,ER and microvessels.(3)Nuclei of neurons had more radiation tolerance compared with the organells to GK.