低剂量伽玛刀照射癫痫大鼠颞叶神经元超微结构的改变及线粒体形态计量分析

Ultrastructural Changes and Quantitative Analysis of Motochondria in Emporal Lobe Neurons of Epilepsy Rats after Exposed to Low-dose Gamma Knife Radiation

目的观察低剂量伽玛刀照射癫痫大鼠颞叶神经元超微结构的变化,探讨线粒体形态改变程度及性质。方法建立大鼠青霉素局灶性癫痫动物模型,将48只SD大鼠分为对照组(A组)、实验组(癫痫模型组,简称B组)和癫痫后伽玛刀照射组(C组)。照射周边剂量12 Gy,等剂量曲线为50%。分别于0.5 h^60 d后取靶区颞叶皮质区制备电镜样本,透射电镜观察,通过计算机图像分析系统对线粒体形态计量分析。结果A组细胞结构基本正常;B组可见神经元细胞质细胞器明显减少空化,线粒体体密度、数密度、比表面和嵴膜密度较对照组明显减少(P<0.05),线粒体平均体积和平均截面积较对照组明显增大(P<0.05)。C组早期与B组基本一致,细胞质内有少量脂褐素,中期和晚期线粒体的各项参数与A组相差不显著,低剂量伽玛刀照射后早期线粒体的平均体积、平均截面积数密度、比表面与A组相差显著(P<0.05),圆球度各组间无明显差异。结论大鼠癫痫发作后其线粒体的形态结构发生明显变化,低剂量伽玛刀照射对神经元的修复有重要作用,本研究认为线粒体参与了癫痫的病理过程。

Objective To observe ultrastructural changes in temporal lobe neurons of epileptic rats after exposed to lowdose gamma knife radiation and discuss characters and degrees of the morphological changes. Methods The rat models of epilepsy were established by injection of penicillin into cortex, forty eight rats were divided randomly into three groups ： blank control group （A）, experimental control group （B） and low-dose gamma knife radiation group （C）. The radiation was carried out with a peripheral dose of 12 Gy and 50% isodose line. The temporal lobe cortex were prepared from the rats at 0.5 h and 60 d respectively after exposure to Gamma Knife, observed by the transmission electron microscopy （ TEM ）, and the morphometric quantitative analysis on the mitochondria was analyzed by the computer image analysis system. Results In Group B, organelles obviously decreased and cavitated, the volume density, numerical density , specific surface and eristae membrane density of mitochondrial decreased obviously （P 〈 0.05） and average volume and sectional area increased remarkably（ P 〈 0.05）. In group C, lipeehromes inereased little, morphology changes compared with Group B to be the same approximately in earlier period, and the changes of Characteristic parameters of mitochondria were not obvious compared with Group A in middle and later period. Conclusion Ultrastructural changes of the mitochondria are obvious after epileptic seizure, low dose Gamma Knife radiation exerts may be one of the important factors on neural restoration, and mitochondria participate in epileptic pathologic process.