ABSTRACТ

Purpose: To explore if the total body γ-irradiation at a dose of 0.1 Gy 7 days prior to acute mixed γ, n-irradiation of the head at the dose of 1 Gy can reduce the harmful effects of neutron irradiation on the hippocampal functions, neuroinflammation and neurogenesis.

Materials and methods: Mice were exposed to γ-radiation alone, mixed γ,n-radiation or combined γ-rays and γ,n-radiation 7 days after γ-irradiation. Two months post-irradiation, mice were tested in Open Field and in the Morris water maze. The content of microglia, astrocytes, proliferating cells and cytokines TGF-β, TNF-α, IL-1β, GFAP levels, hippocampal BDNF, NT-3, NT-4, NGF mRNA expression were evaluated.

Results: Two months after combined irradiation, we observed impaired hippocampus-dependent cognition, which was not detected in mice exposed to γ,n-irradiation. Combined exposure and γ,n-irradiation led to a significant increase in the level of activated microglia and astrocytes in the brains. The level of pro- and anti-inflammatory cytokines in the brain and hippocampal neurotrophine's genes changed differenly after the combined exposure and γ,n-irradiation. The quantity of DCX-positive cells was reduced after γ,n-irradiation exposer alone, but increased after combined irradiation.

Conclusions: Our results indicate radio-adaptive responses in brains of mice that were exposed to low-dose gamma irradiation 7 days prior to acute 1 Gy γ,n-irradiation.

 摘要

目的：探讨头部急性混合γ、n照射1 Gy前7天进行0.1 Gy全身γ照射是否可以减轻中子照射对海马功能的有害影响。神经炎症和神经发生。

材料和方法：在γ-辐射后7天，将小鼠暴露于单独的γ-辐射、混合的γ,n-辐射或组合的γ-射线和γ,n-辐射。辐射后两个月，小鼠在露天场地和莫里斯水迷宫中进行测试。检测小胶质细胞、星形胶质细胞、增殖细胞及细胞因子TGF-β、TNF-α、IL-1β、GFAP含量,海马BDNF、NT-3、NT-4、NGF mRNA表达量。

结果：联合照射两个月后，我们观察到海马依赖性认知受损，而在暴露于 γ,n-照射的小鼠中未检测到这种情况。联合暴露和γ,n-辐射导致大脑中活化的小胶质细胞和星形胶质细胞的水平显着增加。联合照射和γ,n-照射后，大脑和海马神经营养基因中促炎和抗炎细胞因子的水平发生了不同的变化。单独照射γ,n照射后DCX阳性细胞数量减少,但联合照射后DCX阳性细胞数量增加。

结论：我们的结果表明，在急性 1 Gy γ,n 照射前 7 天暴露于低剂量 γ 照射的小鼠大脑中出现放射适应性反应。