College of Life Sciences, Shaanxi Normal University, No. 620, West Chang'an Avenue, Chang'an District, Xi'an, Shaanxi, 710119, People's Republic of China.
Biol Trace Elem Res. 2023 Jul;201(7):3446-3460. doi: 10.1007/s12011-022-03436-8. Epub 2022 Oct 10.
Lead (Pb) becomes a global public health concern for its high toxicology. Birds are sensitive to environmental pollution and Pb contamination exerts multiple negative influences on bird life. Pb also impacts on avian reproductive system. Thus, in this study, we attempted to determine toxicological effects and possible mechanistic pathways of Pb on avian testicular development by using the model species-Japanese quail (Coturnix japonica). Male quail chicks of 1-week-old were exposed to 0, 50, 500, and 1000 ppm Pb concentrations in drinking water for 5 weeks when reaching sexual maturation. The results showed that high Pb doses (500 and 1000 ppm) induced testis atrophy and cloacal gland shrinkage. Microstructural damages of both hypothalamus and testis indicated the disruption of the hypothalamus-pituitary-gonadal (HPG) axis by Pb exposure. The decrease of gonadotropin-releasing hormone (GnRH), luteinizing hormone (LH) and follicle-stimulating hormone (FSH) and testosterone (T) may also imply HPG axis disruption. Moreover, excess testicular oxidative damages featured by increasing reactive oxygen species (ROS) and malondialdehyde (MDA) and decreasing catalase (CAT), glutathione (GSH), superoxide dismutase (SOD), glutathione-S-transferase (GST), and total antioxidant capacity (T-AOC) indicated increasing risks of reproductive dysfunction by Pb. Furthermore, increasing apoptosis and upregulation of gene expression associated with cell death suggested testicular abnormal development. In addition, molecular signaling involved with steroidogenesis in the testis was disturbed by Pb treatment. The study showed that Pb could impair testicular development and reproductive function by morphological and histological injury, hormone suppression, oxidative stress, cell death, and HPG axis disruption.
铅（Pb）因其高毒性而成为全球公共卫生关注的焦点。鸟类对环境污染敏感，Pb 污染对鸟类的生活产生了多种负面影响。Pb 还会影响鸟类的生殖系统。因此，在这项研究中，我们试图通过使用模型物种-日本鹌鹑（Coturnix japonica）来确定 Pb 对鸟类睾丸发育的毒理学影响和可能的机制途径。当达到性成熟时，1 周龄的雄性鹌鹑雏鸡被暴露于饮用水中的 0、50、500 和 1000 ppm Pb 浓度下 5 周。结果表明，高 Pb 剂量（500 和 1000 ppm）诱导睾丸萎缩和泄殖腔腺萎缩。下丘脑和睾丸的微观结构损伤表明 Pb 暴露破坏了下丘脑-垂体-性腺（HPG）轴。促性腺激素释放激素（GnRH）、促黄体生成素（LH）和促卵泡激素（FSH）和睾酮（T）的减少也可能暗示 HPG 轴的破坏。此外，过量的睾丸氧化损伤特征为活性氧（ROS）和丙二醛（MDA）增加，而过氧化物酶（CAT）、谷胱甘肽（GSH）、超氧化物歧化酶（SOD）、谷胱甘肽-S-转移酶（GST）和总抗氧化能力（T-AOC）减少，表明 Pb 增加了生殖功能障碍的风险。此外，细胞死亡相关的凋亡增加和基因表达上调表明睾丸发育异常。此外，Pb 处理还干扰了睾丸中类固醇生成的分子信号转导。研究表明，Pb 可以通过形态和组织学损伤、激素抑制、氧化应激、细胞死亡和 HPG 轴破坏来损害睾丸发育和生殖功能。
