立体定向照射所致脑损伤病理及靶区的三维重建研究

Pathological Study and Three-dimensional Reconstruction on Rats Brain Injury Induced by stereotactic Irradiation

本实验采用常规病理、原位杂交、透射电镜方法 ,观察了使用旋转式头部γ -刀单次2 0 0Gy定点照射后 ,在不同时间 ,大鼠右侧尾状核头部靶区和靶周围区的病理改变 ,并使用计算机立体重建技术 ,对坏死靶区进行了三维立体重建。结果表明 :γ -刀照射后脑损伤病变经历急性水肿 (照射后即刻至 14天 )、坏死形成 ( 2 1天至 2个月 )、吸收 ( 3至 6个月 )、增生 ( 9至 12个月 ) 4个阶段 ;照射后 2小时血脑屏障通透性即开始增加 ,其程度在一定时间内与照射后生存时间呈正相关 ;血管内皮细胞和胶质细胞超微结构的改变先于神经元 ;照射引起TNF -α、IL - 1βmRNA表达增加 ,照射前给予地塞米松可以抑制其表达 ;重建的坏死靶区呈尖端向前的不规则空间构型 ,平均体积为 2 32 .2 7± 4 .60mm3。

In order to guide clinical radiotherapy including the treatment of functional disorders with rotate headγ-knife, we studied the pathological changes in the right caudate nucleus of the rats brain which were locally irradiated with a single-fraction dose of 200 Gy γ-rays. We also observed the preventive and therapeutic effect of dexamethasone on the radiation-induced brain injury. In the present experiment, Gross, microscopic and ultramicroscopic examinations, and thee-dimensional reconstruction were performed, and in situ hybridization was used to detect the expression of TNF-α and IL-1β mRNA in the irradiated brain tissue. Our results showed that: The pathological changes went through 4 stages, (1) Cerebral edema (0-14 days after irradiation); (2) Necrosis of the injured tissue (21 day to 2 month after irradiation); (3) Scavenging of the necrotic tissue (3 to 6 month after irradiation); (4) Hyperplasia stage (9-12 month after irradiation). We also found that, the permeability of the blood-brain barrier began to be increased 2 hours after irradiation, and the increasing degree was in positive correlation with their survival period; The ultrastructural changes of the endotheliocytes and the gliocytes were prior to that of the neurons; expression of TNF-α and IL-1β mRNA in the irradiated brain tissue was increased and the dexamethasone could inhibit the expression of TNF-α and IL-1β if the rats were treated with it before irradiation. The formation of necrotic cavitation is irregular and the mean volume of necrotic cavitation is 232.27±4.60mm 3.