Feng Huichao, Cui Yahuan, Liu Jing, Liu Meiyi, Zhou Wei, Yan Zhenyu, Zhang Haixia, Wang Yingman, Wang Xueming, Liu Xiaomin, Chen Naiyao
Department of Hematology, Affiliated Hospital of North China University of Science and Technology, Tangshan, China.
Gamma Knife Center, Department of Neurological Surgery, Tianjin University, Tianjin, China.
Dose Response. 2022 May 20;20(2):15593258221100593. doi: 10.1177/15593258221100593. eCollection 2022 Apr-Jun.
To determine the effect of the autophagy inhibitor, 3-methyladenine (3-MA), on cognitive function changes, microglia activity, neuronal apoptosis, and inflammation in rats following radiation-induced brain injury.
The following groups were established: control, model, and 3-MA. A rat model of radiation-induced brain injury was generated with a medium dose of X-rays. A Morris water maze was used to observe the cognitive function of the rats. H&E staining was used to observe the pathological changes in the hippocampus. The morphological and quantitative changes of neuronal nuclear (NeuN)-positive neurons and Iba-1-positive microglia in the ipsilateral hippocampus were analyzed by immunohistochemistry. Western blot analysis was done to measure the changes of NeuN ionized calcium binding adapter molecule 1(Iba-1) and apoptosis-related proteins. Immunofluorescence staining of Iba-1 and Microtuble-associated protein light chain 3 (LC3) was done to evaluate the changes in microglia autophagy. TUNEL staining was used to detect apoptosis in the hippocampus. Enzyme-Linked Immunosorbent Assay was used to detect the levels of TNF-α and IL-6 as a measure of the inflammatory response in the hippocampus.
After irradiation, the nucleus of the neurons in the hippocampus was constricted, the pyramidal tract structure was disordered, neuronal apoptosis was increased ( < .001), the expression of microglia increased ( < .01), autophagy was increased ( < .05), and conversion of microglia to the M2 type increased ( < .05). After 3-MA administration, the level of autophagy decreased ( < .05), the damage to the hippocampal region was reduced, neuronal apoptosis decreased ( < .01), and the activity of the microglia decreased ( < .01).
Radiation can active the Microglia. 3-MA inhibits autophagy and excessive activity in microglia, and promotes the conversion of microglia from the M1 to the M2 type, thereby promoting the recovery of brain tissue following radiation exposure.
确定自噬抑制剂3-甲基腺嘌呤（3-MA）对辐射诱导脑损伤大鼠认知功能变化、小胶质细胞活性、神经元凋亡和炎症的影响。
设立以下几组：对照组、模型组和3-MA组。采用中等剂量X射线建立辐射诱导脑损伤大鼠模型。使用Morris水迷宫观察大鼠的认知功能。采用苏木精-伊红（H&E）染色观察海马体的病理变化。通过免疫组织化学分析同侧海马体中神经元核（NeuN）阳性神经元和离子钙结合衔接分子1（Iba-1）阳性小胶质细胞的形态和数量变化。进行蛋白质免疫印迹分析以测量NeuN、Iba-1和凋亡相关蛋白的变化。对Iba-1和微管相关蛋白轻链3（LC3）进行免疫荧光染色以评估小胶质细胞自噬的变化。采用末端脱氧核苷酸转移酶介导的缺口末端标记（TUNEL）染色检测海马体中的细胞凋亡。使用酶联免疫吸附测定法检测肿瘤坏死因子-α（TNF-α）和白细胞介素-6（IL-6）水平，作为海马体炎症反应的指标。
照射后，海马体神经元细胞核收缩，锥体束结构紊乱，神经元凋亡增加（P<0.001） , 小胶质细胞表达增加（P<0.01） , 自噬增加（P<0.05） , 小胶质细胞向M2型转化增加（P<0.05）。给予3-MA后，自噬水平降低（P<0.05） , 海马区损伤减轻，神经元凋亡减少（P<0.01） , 小胶质细胞活性降低（P<0.01）。
辐射可激活小胶质细胞。3-MA抑制自噬和小胶质细胞的过度活性，并促进小胶质细胞从M1型向M2型转化，从而促进辐射暴露后脑组织的恢复。
