Araujo Ulisses C, Krahe Thomas E, Ribeiro-Carvalho Anderson, Gomes Regina A A, Lotufo Bruna M, Moreira Maria de Fátima R, de Abreu-Villaça Yael, Manhães Alex C, Filgueiras Cláudio C
Laboratório de Neurofisiologia, Departamento de Ciências Fisiológicas, Instituto de Biologia Roberto Alcantara Gomes, Centro Biomédico, Universidade Do Estado Do Rio de Janeiro, Avenida Professor Manuel de Abreu 444, 5 andar, Vila Isabel, Rio de Janeiro, RJ 20550-170 Brazil.
Departamento de Psicologia, Pontifícia Universidade Católica Do Rio de Janeiro, Rio de Janeiro, Brazil.
Toxicol Res. 2020 Jun 5;37(1):115-124. doi: 10.1007/s43188-020-00045-2. eCollection 2021 Jan.
Recent evidence points to the relationship between lead toxicity and the function of the hypothalamic-pituitary-adrenal axis, which suggests that lead exposure could influence how an individual cope with stress. Here we test this hypothesis by investigating the behavioral effects of lead exposure in mice during the forced swimming test (FST), a parading in which animals are exposed to a stressful situation and environment. Swiss mice received either 180 ppm or 540 ppm of lead acetate (Pb) in their ad-lib water supply for 60-90 days, starting at postnatal day 30. Control (Ctrl) mice drank tap water. At the end of the exposure period, mice were submitted to a 5-min session of FST or to an open-field session of the same duration. Data from naïve animals showed that corticosterone levels were higher for animals tested in the FST compared to animals tested in the open-field. Blood-lead levels (BLL) in Pb-exposed mice ranged from 14.3 to 106.9 µg/dL. No differences were observed in spontaneous locomotion between Ctrl and Pb-exposed groups in the open-field. However, in the FST, Pb-treated mice displayed higher swimming activity than Ctrl ones and this effect was observed even for animals with BLL higher than 20 µg/dL. Furthermore, significant differences in brain glutathione levels, used as an indicator of led toxicity, were only observed for BLL higher than 40 µg/dL. Overall, these findings suggest that swimming activity in the FST is a good indicator of lead toxicity and confirm our prediction that lead toxicity influences behavioral responses associated to stress.
最近的证据表明铅毒性与下丘脑 - 垂体 - 肾上腺轴的功能之间存在关联，这表明铅暴露可能会影响个体应对压力的方式。在此，我们通过研究铅暴露对小鼠在强迫游泳试验（FST）中的行为影响来验证这一假设，FST是一种让动物暴露于应激情况和环境的试验。从出生后第30天开始，瑞士小鼠在其自由饮用的水中分别摄入180 ppm或540 ppm的醋酸铅（Pb），持续60 - 90天。对照组（Ctrl）小鼠饮用自来水。在暴露期结束时，将小鼠进行5分钟的FST试验或相同持续时间的旷场试验。来自未处理动物的数据显示，与旷场试验中的动物相比，FST试验中的动物皮质酮水平更高。铅暴露小鼠的血铅水平（BLL）在14.3至106.9 μg/dL之间。在旷场试验中，Ctrl组和铅暴露组之间的自发运动未观察到差异。然而，在FST中，铅处理的小鼠比Ctrl组小鼠表现出更高的游泳活性，甚至在BLL高于20 μg/dL的动物中也观察到了这种效应。此外，仅在BLL高于40 μg/dL时才观察到用作铅毒性指标的脑谷胱甘肽水平存在显著差异。总体而言，这些发现表明FST中的游泳活性是铅毒性的良好指标，并证实了我们的预测，即铅毒性会影响与应激相关的行为反应。
