Treatment of brain cancer, glioma, can cause cognitive impairment as a side‐effect, possibly because it disrupts the integrity of the hippocampus, a structure vital for normal memory. Radiotherapy is commonly used to treat glioma, but the effects of irradiation on the brain are still poorly understood, and other biological effects have not been extensively studied. Here, we exposed healthy adult male rats to moderate‐dose irradiation of the head. We found no effect of irradiation on systemic inflammation, weight gain or gut microbiota diversity, although it increased the abundance of Bacteroidaceae family, namely Bacteroides genus in the gut microbiota. Irradiation had no effect on long‐term potentiation in the CA3‐CA1 synapse or endogenous hippocampal electrophysiology, but it did reduce adult hippocampal neurogenesis and impaired short‐term spatial recognition memory. However, no overall cognitive impairment was observed. To summarize, our results suggest that in adult male rats head irradiation does not compromise health or cognition overall even though the number of new, adult‐born hippocampal neurons is decreased. Thus, the sole effects of head irradiation on the body, brain and cognition might be less harmful than previously thought, and the cognitive decline experienced by cancer patients might originate from physiological and mental effects of the disease itself. Therefore, to increase the translational value of animal studies, the effects of irradiation should be studied together with cancer, in older animals, using varying irradiation protocols and doses.

中文翻译：

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头部照射可减少成年海马神经发生并损害空间记忆，但可保持大鼠的整体健康状况

脑癌，神经胶质瘤的治疗可能会导致认知障碍，这可能是因为它破坏了对正常记忆至关重要的海马结构的完整性。放射疗法通常用于治疗神经胶质瘤，但是对脑辐射的影响仍然知之甚少，其他生物学作用尚未得到广泛研究。在这里，我们将健康的成年雄性大鼠暴露于中等剂量的头部。我们发现辐照对全身炎症，体重增加或肠道菌群多样性没有影响，尽管它增加了拟杆菌科（Bacteroidides）的丰度。肠道菌群中的属。辐射对CA3-CA1突触或内源性海马电生理的长期增强没有影响，但确实减少了成人海马神经发生并削弱了短期空间识别记忆。但是，没有观察到整体认知障碍。总而言之，我们的结果表明，即使成年新生海马神经元的数量减少，成年雄性大鼠的头部照射也不会损害整体健康或认知。因此，头部照射对身体，大脑和认知的唯一影响可能没有以前想象的那么有害，癌症患者经历的认知能力下降可能源于疾病本身的生理和心理影响。因此，为了提高动物研究的翻译价值，