低剂量伽玛刀照射癫癎大鼠脑神经元的超微结构研究

Ultrastructural study of neurons in cortex and hippocampus of epilepsy rats after exposed to low-dose Gamma Knife radiation

目的探索伽玛刀治疗原发性癫的细胞学机理。方法建立大鼠皮质青霉素局灶性癫癎模型,将SD大鼠随机分为实验组、实验对照组和对照组。照射周边剂量12 Gy, 等剂量曲线为50%。分别于0.5 h^2个月后取靶区皮质及海马标本制备光镜、常规透射电镜样品。结果癫癎模型鼠可见较多凋亡神经元,而癫癎模型鼠经低剂量伽玛刀照射后同时程的神经元改变较轻微,凋亡细胞少见。结论凋亡参与了青霉素致癫癎发作后海马神经元的死亡过程,低剂量伽玛刀照射对抑制神经元的死亡过程有重要作用。

Objective To study the cell-level mechanism responsible for the treatment of epilepsy with Gamma Knife. Methods The rat models of epilepsy were made by injection of penicillin into cortex. Forty-eight rats were divided randomly into three groups: experimental group, experimental control group, and blank control group. The radiation was carried out with a peripherial dose of 12Gy and isocenter of 50%. The cortex and hippocampus were harvested from the rats at 0.5h and 2 months respectively after exposure to Gamma Knife and studied by light microscopy and conventional transmission electron microscopy. Results Apoptotic neurons were found in epilepsy model rats. The changes in earlier period included agglutination and condensation of perinuclear chromatin, and shrinkage, distortion, and discontinuousness of nuclear membrane. The changes in later period included the break of nuclear membrane, karyopyknosis, swelling of organelles, such as rough endoplasmic reticulum and mitochondrion, break, extinction and vacuolation of mitochondrial crista. The epilepsy model rats receiving low-dose gamma knife radiation, however, displayed less apoptotic neurons and little changes in neurons at the corresponding period. Conclusions Apoptosis plays an important role in the death of hippocampal neurons after epileptic seizure resulting from penicillin, and low-dose Gamma Knife radiation exerts definitive effect on inhibition of neuron death.