大鼠正常脑组织伽玛刀照射后MRI表现及GFAP表达的实验研究

目的研究伽玛刀(Gamma knife)照射大鼠尾状核后胶原纤维酸性蛋白(GFAP)的表达随时间的变化,探讨星形胶质细胞的增殖与放射损伤的关系以及放射性损伤的影像学表现。方法40只成年雌性Wistar大鼠,10只大鼠作为对照组。30只大鼠接受MASEP-SRRS型伽玛刀8mm准直器以50Gy(50%等剂量线)照射大鼠右侧尾状核。照射后的30只大鼠随机分为3组,每组10只。不同组别的大鼠分别在照射后第1,4,12周深度麻醉下断头取出脑组织,行免疫组织化学染色观察GFAP的表达,并使用梯度柱法测量脑组织的比重。大鼠处死前接受1.5TMRI轴位平扫和增强扫描。结果MRI提示照射后第12周可发现受照大鼠尾状核T2相可见受照区信号增高,增强T1相可见受照区强化明显。对照组大鼠脑组织内均匀散在分布少数GFAP阳性细胞,轮廓清楚,星形突起纤细。照射后4周靶区内GFAP阳性细胞数目开始增多,细胞形态变得不规则。至12周时GFAP阳性细胞进一步增多,胞体变大,细胞突起粗大不规则,胞浆染色呈深棕色。照射后第4周和第12周检测到照射侧脑组织比重与对侧相比显著减轻。结论GFAP可作为衡量脑放射性损伤的指标。照射后早期即出现脑水肿反应和血脑屏障破坏。在不同时间点的病理变化可以通过MRI信号观察不同时间点的病理变化。

An experimental study on the expression of glial fibrillary acidic protein and MRI imaging changes in the normal Wistar rat brains after Gamma knife radiosurgery

Objective To explore the time-related expression of GFAP and MRI imaging changes in the normal rat brain during the subacute phase after Gamma knife irradiationy.Methods 40 adult female Wistar rats were were enrolled into the study.Ten rats served as controlled group while the other thirty rats underwent Gamma knife.The right caudate-putamen nucleus was selected as the target of irradiation.A 8 mm collimator was used to transmit 50 Gy to the target region.Rats were killed 1st,4th and 12nd weeks after gamma ...