伽玛刀照射后正常大鼠脑形态学变化的观察

为研究伽玛刀照射后正常大鼠脑组织形态学变化与时间和剂量的关系，并探讨晚期放射性坏死的发生机制，以大鼠右侧尾状核头部为照射靶点，伽玛刀照射剂量分别为20、50、75、160Gy，准直器直径4mm，应用HE、Nissl、Luxol Fast Blue染色和免疫组化方法观察从伽玛刀照射开始到晚期坏死发生过程中的形态学变化。结果显示，在晚期坏死灶出现之前的潜伏期内，靶区内病变主要包括两个方面：①微血管系统改变，即毛细血管增生、微血管腔扩张、管壁增厚、血管周围组织间隙水肿；②星形胶质细胞肥大、增生。研究表明，大鼠靶区内的形态学变化具有时间和剂量依赖性，微血管系统改变和星形胶质细胞的损伤都可能导致晚期坏死的发生。

HISTOLOGICAL CHANGES IN NORMAL RAT BRAIN AFTER GAMMA IRRADIATION

To study time and dose related changes after gamma knife radiosurgery (GKR) in rat brain, right caudate nucleuses of rats were irradiated by OUR XGD gamma units. The maximum dosages of 20,50,75 and 160Gy were given using a 4 mm collimator. HE, Nissl, Luxol fast blue staining and immunohistochemistry were utilized to observe histological changes.Histological changes in the right caudate nucleuses such as microvessel injury, which appeared as telangiectasia, vasodilatation, vessel wall thickening and edema, and astrocyte changes, which appeared as hypertrophy and proliferation, were observed at various time points after GKR. These findings demonstrate time dependent and dosage dependent changes are found in normal cerebral tissue after GKR. These results provide an explanation of the process taking place during the latent period before delayed radiation necrosis develops.