Department of Biology, Faculty of Sciences, University of A Coruña, 15008 A Coruña, Spain.
Centro Interdisciplinar de Química y Biología, (CICA), University of A Coruña, 15071 A Coruña, Spain.
Int J Mol Sci. 2024 Apr 30;25(9):4933. doi: 10.3390/ijms25094933.
Manganese (Mn), a cofactor for various enzyme classes, is an essential trace metal for all organisms. However, overexposure to Mn causes neurotoxicity. Here, we evaluated the effects of exposure to Mn chloride (MnCl) on viability, morphology, synapse function (based on neurogranin expression) and behavior of zebrafish larvae. MnCl exposure from 2.5 h post fertilization led to reduced survival (60%) at 5 days post fertilization. Phenotypical changes affected body length, eye and olfactory organ size, and visual background adaptation. This was accompanied by a decrease in both the fluorescence intensity of neurogranin immunostaining and expression levels of the neurogranin-encoding genes and , suggesting the presence of synaptic alterations. Furthermore, overexposure to MnCl resulted in larvae exhibiting postural defects, reduction in motor activity and impaired preference for light environments. Following the removal of MnCl from the fish water, zebrafish larvae recovered their pigmentation pattern and normalized their locomotor behavior, indicating that some aspects of Mn neurotoxicity are reversible. In summary, our results demonstrate that Mn overexposure leads to pronounced morphological alterations, changes in neurogranin expression and behavioral impairments in zebrafish larvae.
锰 (Mn) 是多种酶类的辅助因子，是所有生物必需的痕量金属。然而，过量暴露于锰会导致神经毒性。在这里，我们评估了氯化锰 (MnCl) 暴露对斑马鱼幼虫活力、形态、突触功能（基于神经颗粒蛋白表达）和行为的影响。从受精后 2.5 小时开始暴露于 MnCl 会导致受精后 5 天的存活率降低（60%）。表型变化影响体长、眼睛和嗅觉器官大小以及视觉背景适应。这伴随着神经颗粒蛋白免疫染色的荧光强度和神经颗粒蛋白编码基因 和 的表达水平降低，表明存在突触改变。此外，MnCl 的过度暴露导致幼虫表现出姿势缺陷、运动活性减少和对光环境的偏好受损。从鱼水中去除 MnCl 后，斑马鱼幼虫恢复了它们的色素模式并使它们的运动行为正常化，这表明 Mn 的一些神经毒性是可逆的。总之，我们的结果表明，Mn 过度暴露会导致斑马鱼幼虫明显的形态改变、神经颗粒蛋白表达变化和行为障碍。
