Zoology Department, Faculty of Science, Assiut University, Assiut, 71516, Egypt.
Laboratory of Immunology, Zoology Department, Faculty of Science, Assiut University, Assiut, 71516, Egypt.
Environ Sci Pollut Res Int. 2020 Mar;27(8):8684-8695. doi: 10.1007/s11356-019-07572-y. Epub 2020 Jan 6.
Exposure to ionizing radiation emitted from natural sources induces many health hazards. The response to ionizing radiation involves a number of mediators including inflammatory cytokines and free radicals which mediate immunosuppression. The present study aimed to monitor the impact of exposure to natural radioactive rocks from the Egyptian eastern desert on the primary immune organs. Therefore, three experimental groups (15 rats per group) were used: group I included the control non-irradiated rats; group II included rats that were exposed for 28 consecutive days to natural radioactive rocks from the Egyptian eastern desert (IR/R group); and group III (positive control group) included rats that were exposed to high dose of γ-rays (4 Gy/14 days for 28 days) (IR/γR group). We found that rats of both the IR/R and IR/γR groups exhibited pathological alterations in the architecture of the primary immune organs (bone marrow and thymus). Additionally, the levels of C-reactive protein (CRP), proinflammatory cytokines (IL-1β, IL-6 and TNF-α), and reactive oxygen species (ROS) were significantly increased in the IR/R and IR/γR groups compared to the control group. Furthermore, rats from the IR/R and IR/γR groups exhibited significant increase in the activity of caspase-3 and caspase-9 and subsequently exhibited a significant increase in the apoptosis of PBMCs compared with the control group. Most importantly, apoptosis induction in the PBMCs was associated with increased expression of cyclin B1 and decreased expression of cyclin D1 and survivin compared with the control non-irradiated group. Taken together, our data demonstrated that consecutive exposure to natural radioactive rocks from the Egyptian eastern desert could dampen the immune response through damaging the architectures of the immune system and mediating serious health problems to the population inhabiting this region.
暴露于天然来源的电离辐射会引起许多健康危害。电离辐射的反应涉及许多介质，包括炎症细胞因子和自由基，它们介导免疫抑制。本研究旨在监测暴露于埃及东部沙漠天然放射性岩石对初级免疫器官的影响。因此，使用了三个实验组（每组 15 只大鼠）：第一组包括未照射的对照组；第二组包括连续 28 天暴露于埃及东部沙漠天然放射性岩石的大鼠（IR/R 组）；第三组（阳性对照组）包括暴露于高剂量γ射线（4Gy/14 天，共 28 天）的大鼠（IR/γR 组）。我们发现，IR/R 和 IR/γR 组的大鼠初级免疫器官（骨髓和胸腺）的结构均发生了病理改变。此外，与对照组相比，IR/R 和 IR/γR 组大鼠的 C 反应蛋白（CRP）、促炎细胞因子（IL-1β、IL-6 和 TNF-α）和活性氧（ROS）水平显著升高。此外，与对照组相比，IR/R 和 IR/γR 组大鼠的 caspase-3 和 caspase-9 活性显著增加，随后 PBMCs 的凋亡显著增加。最重要的是，与未照射的对照组相比，PBMCs 的凋亡诱导与细胞周期蛋白 B1 的表达增加和细胞周期蛋白 D1 和 survivin 的表达减少有关。总之，我们的数据表明，连续暴露于埃及东部沙漠的天然放射性岩石会通过破坏免疫系统的结构并对居住在该地区的人群造成严重的健康问题，从而抑制免疫反应。
