接触颗粒物 2.5 (PM2.5) 对多个器官系统有害。鉴于衰老还会改变免疫系统的细胞结构和反应以及下丘脑-垂体-肾上腺、性腺和甲状腺轴的功能障碍，因此有必要研究长期暴露于 PM2.5 是否与衰老在这些方面存在相互作用。在这项研究中，两个月大的 Sprague-Dawley 大鼠暴露于现实世界的 PM2.5 中 16 个月。 PM2.5暴露降低了雄性大鼠外周血中CD4 T细胞和CD8 T细胞的相对数量，并增加了B细胞的相对数量。相反，雌性大鼠血液中 CD4 T 细胞的相对数量仅减少。这些变化导致男女循环系统中促炎因子白细胞介素 6 和肿瘤坏死因子 α 水平升高，女性白细胞介素 1β 水平也有所升高。此外，白介素 6 升高仅在女性受试者的海马体中可见，而肿瘤坏死因子 α 浓度升高在女性大脑区域广泛存在，但仅限于男性下丘脑。男性和女性接触 PM2.5 后，荷尔蒙均出现显着下降。其中包括生物分子的减少，例如由下丘脑-垂体-肾上腺轴产生的促肾上腺皮质激素释放激素和皮质醇，以及由下丘脑-垂体-甲状腺轴产生的甲状腺释放激素和三碘甲状腺原氨酸。来自下丘脑-垂体-性腺轴的激素成分，如促性腺激素释放激素、黄体生成素和卵泡刺激素也减少了。雄性大鼠独有的是促肾上腺皮质激素水平的降低，而促甲状腺激素水平的下降是雌性大鼠所独有的。还注意到性别特异性激素的减少，包括睾酮、雌二醇和黄体酮。这些发现极大地丰富了我们对 PM2.5 相互作用（尤其是对老年人群）潜在的长期健康影响的理解。版权所有 © 2024 Cuiying Liu 等人。

Exposure to particulate matter 2.5 (PM2.5) is detrimental to multiple organ systems. Given the factor that aging also alters the cellularity and response of immune system and dysfunction of hypothalamic-pituitary-adrenal, -gonad and -thyroid axes, it is imperative to investigate whether chronic exposure to PM2.5 interacts with aging in these aspects. In this study, two-months-old Sprague-Dawley rats were exposed to real world PM2.5 for 16 months. PM2.5 exposure diminished the relative numbers of CD4+ T cells and CD8+ T cells and increased the relative number of B cells in the peripheral blood of male rats. Conversely, only reduced relative number of CD4+ T cells was seen in the blood of female rats. These shifts resulted in elevated levels of proinflammatory factors interleukin-6 and tumor necrosis factor-α in the circulatory systems of both sex, with females also evidencing a rise in interleukin-1β levels. Moreover, heightened interleukin-6 was solely discernible in the hippocampus of female subjects, while increased tumor necrosis factor-α concentrations were widespread in female brain regions but confined to the male hypothalamus. Notable hormonal decreases were observed following PM2.5 exposure in both sex. These comprised declines in biomolecules such as corticotrophin-releasing hormone and cortisol, generated by the hypothalamic-pituitary-adrenal axis, and thyroid-releasing hormone and triiodothyronine, produced by the hypothalamic-pituitary-thyroid axis. Hormonal elements such as gonadotropin-releasing hormone, luteinizing hormone, and follicle-stimulating hormone, derived from the hypothalamic-pituitary-gonad axis, were also diminished. Exclusive to male rats was a reduction in adrenocorticotropic hormone levels, whereas a fall in thyroid-stimulating hormone was unique to female rats. Decreases in sex-specific hormones, including testosterone, estradiol, and progesterone, were also noted. These findings significantly enrich our comprehension of the potential long-term health repercussions associated with PM2.5 interaction particularly among the aging populace.Copyright © 2024 Cuiying Liu et al.