伽玛刀对癫痫大鼠模型的治疗作用及机制研究

目的 研究伽玛刀照射对癫痫大鼠的放射生物学作用,探讨伽玛刀治疗癫痫的作用机制.方法 制备海人酸大鼠癫痫模型,利用自行设计的伽玛刀动物定向头架,分别应用100Gy和20Gy的伽玛射线对癫痫大鼠海马组织进行照射,观察大鼠行为学、脑电图、MRI及超微结构、脑组织氨基酸含量及GABA能神经元表达变化.结果 伽玛刀照射后大鼠癫痫发作次数明显减少.100Gy组照射后2个月MRI表现为靶区高信号,20Gy组5个月MRI未见改变.伽玛刀照射后兴奋性氨基酸含量显著低于癫痫组,GABA能神经元表达低于正常,但高于癫痫组.结论 伽玛刀照射对癫痫大鼠具有治疗作用,高剂量伽玛射线(100Gy)对致痫灶有毁损作用.低剂量伽玛射线(20Gy)通过抑制兴奋性神经元释放兴奋性氨基酸使癫痫发作减少.

Effect and mechanism of Gamma knife therapy on epilepsy rats

Objective To investigate the radiobiological response and its mechanism of Gamma knife on epilepsy rats.Method The animal model of epilepsy was established with kainic acid injection.Epileptic rats were irradiated by different doses of Gamma knife with stereotactic lathe-hedd for rats.Changes of behavioral,EEG,morphological uhrastructure,MRI,concentration of amino acid and expression of GABA were detected.Results Behavior and EEG demonstrated that seizure gradually reduce after irradiation.Imaging changes of target could be observed at dose of 100Gy in 2 month but no changes at dose of 20Gy in 5 month.Concentration of excitatory amino acid after irradiation by Gamma knife is lower than that of epilepsy rats.The expression of GABA showed lower than normal but higher than epilepsy rats.Conclusions Therapeutic effect of gamma knife for epilepsy could be observed but the epileptogenic focus was destroyed at high dose(100Gy).Excitatory neurons could be inhibited by irradiation of low dose (20Gy)gamma rays due to the decrease of excitatory amino acid release.