Rodina A V, Vysotskaya O V, Zhirnik A S, Smirnova O D, Parfenova A A, Strepetov A N, Semochkina Yu P, Nesterenko M V, Moskaleva E Yu
National Research Center "Kurchatov Institute", Moscow, Russia.
Laktobio LLC, Moscow, Russia.
Dokl Biochem Biophys. 2024 Dec;519(1):556-563. doi: 10.1134/S1607672924701205. Epub 2024 Oct 31.
The purpose of the study was to investigate the effect of γ,n-irradiation of the mouse head on the brain cells damage, behavior, and cognition and to examine the possibility of using lactoferrin (LF) to alleviate radiation-induced impairments.
Mouse heads were irradiated in a beam of neutrons and gamma rays from the IR-8 nuclear reactor. The brain cells of control and irradiated mice were isolated using Percoll. Neurons and resting and activated microglial cells were analyzed using the fluorescently labeled antibodies and flow cytometry. The level of DNA double-strand breaks in neurons was determined by γH2AX histone content. Cytokine gene expression in the hippocampus was studied by RT-PCR. Behavior and cognitive functions were studied using the open field, Morris water maze, and novel object recognition tests. LF was isolated from female colostrum by preparative ion-exchange chromatography and purified by affinity chromatography on heparin-Sepharose.
γ,n-Irradiation of the mouse head at a dose of 1.5 Gy led to an increase in the level of DNA double-strand breaks in neurons. Twenty-four hours after irradiation the total number of cells and the number of neurons in the isolated fraction of brain cells decreased, but the number of microglial cells remained unchanged. The number of resting and activated microglia did not change within 3-72 h after γ,n-irradiation. The expression level of the TNFα, IL-1β, and IL-6 genes increased 2 months after γ,n-irradiation of the mouse head at a dose of 1.5 Gy, indicating the development of neuroinflammation. At this time, irradiated mice demonstrated the anxiety-like behavior and impaired spatial and episodic memory. A single i.p. administration of human LF to mice immediately after γ,n-irradiation of the head did not affect the observed radiation-induced disturbances, but decreased the gene expression levels of TNFα, IL-1β, and IL-6 pro-inflammatory cytokines and increased the gene expression level of TGFβ anti-inflammatory cytokine in the hippocampus 2 months after radiation exposure. The obtained results indicate a partial decrease in the level of hippocampal neuroinflammation of irradiated animals treated with LF.
γ,n-Irradiation of the mouse head at a dose of 1.5 Gy leads to DNA damage of neurons and the decrease in the number of neurons. Microglia cells are more resistant to such radiation exposure. Late after head-only γ,n-irradiation, mice develop neuroinflammation, which is detected by an increase in the pro-inflammatory cytokine gene expression in the hippocampus and also by anxiety-like behavior and impaired cognitive functions. A single LF administration leads to a partial decrease in the neuroinflammation level, but does not affect the other studied parameters. The optimal dosing regimen of LF remains to be determined to preserve cognitive functions after γ,n-irradiation of the brain.
本研究旨在探讨小鼠头部γ，n射线照射对脑细胞损伤、行为和认知的影响，并研究使用乳铁蛋白（LF）减轻辐射诱导损伤的可能性。
小鼠头部在IR-8核反应堆产生的中子和γ射线束中进行照射。使用Percoll分离对照小鼠和照射小鼠的脑细胞。使用荧光标记抗体和流式细胞术分析神经元以及静息和活化的小胶质细胞。通过γH2AX组蛋白含量测定神经元中DNA双链断裂的水平。通过RT-PCR研究海马中细胞因子基因的表达。使用旷场试验、莫里斯水迷宫试验和新物体识别试验研究行为和认知功能。通过制备型离子交换色谱从雌性初乳中分离LF，并通过肝素-琼脂糖亲和色谱进行纯化。
以1.5 Gy的剂量对小鼠头部进行γ，n射线照射导致神经元中DNA双链断裂水平增加。照射后24小时，分离的脑细胞部分中的细胞总数和神经元数量减少，但小胶质细胞数量保持不变。γ，n射线照射后3 - 72小时内，静息和活化小胶质细胞的数量没有变化。以1.5 Gy的剂量对小鼠头部进行γ，n射线照射2个月后，TNFα、IL-1β和IL-6基因的表达水平升高，表明发生了神经炎症。此时，照射小鼠表现出焦虑样行为以及空间和情景记忆受损。在头部γ，n射线照射后立即对小鼠进行单次腹腔注射人LF，并不影响观察到的辐射诱导的干扰，但在辐射暴露2个月后，降低了海马中TNFα、IL-1β和IL-6促炎细胞因子的基因表达水平，并增加了TGFβ抗炎细胞因子的基因表达水平。所得结果表明，用LF治疗的照射动物海马神经炎症水平部分降低。
以1.5 Gy的剂量对小鼠头部进行γ，n射线照射会导致神经元DNA损伤和神经元数量减少。小胶质细胞对这种辐射暴露更具抗性。仅头部γ，n射线照射后晚期，小鼠会发生神经炎症，这可通过海马中促炎细胞因子基因表达增加以及焦虑样行为和认知功能受损来检测。单次给予LF会导致神经炎症水平部分降低，但不影响其他研究参数。为了在脑部γ，n射线照射后保留认知功能，LF的最佳给药方案仍有待确定。
