Department of Biological Sciences, University of Calgary, Calgary, AB, T2N 1N4, Canada.
Department of Biology, Wilfrid Laurier University, Waterloo, ON, Canada.
Bull Environ Contam Toxicol. 2024 Jul 16;113(2):14. doi: 10.1007/s00128-024-03922-w.
Total suspended solids (TSS) are a major contributor of anthropogenic impacts to aquatic systems. TSS exposure have been shown to affect the function of gills, but the mode of action is unclear. Zebrafish (Danio rerio) is emerging as an excellent model for mechanistic toxicology, and as there are no baseline studies on TSS effects in zebrafish gills, we tested the hypothesis that environmental concentrations of TSS damages gill structure and function in this species. Adult zebrafish were exposed to either 0, 10, 100, 500, 1000, or 2000 mg/L TSS for 4 days to assess the gill morphology. The minimal concentration that affected the gill structure was further tested for the distribution of key ion transporters, including Na/K- ATPase (NKA) and vacuolar-type H-ATPase (VHA), using confocal microscopy. Our results reveal that TSS concentration as low as 100 mg/L alters the morphology of gills, including greater filament thickness, lamellae thickness, and epithelial lifting. This was also associated with a reduction in NKA immunoreactive (IR) cell count and intensity in the 100 mg/L TSS group, while there was neither a change in the VHA-IR cell count or expression nor the transcript abundance of atp6v1a and atp1a1a4 in the gills. Markers of stress response in these animals, including levels of cortisol, glucose, lactate, and glycogen were not altered after 4 days of TSS exposure. Overall, environmentally relevant concentrations of TSS can damage the gill structure and function in zebrafish and has the potential to enhance the toxicity of contaminants acting via the gills.
总悬浮固体（TSS）是人为因素对水生系统影响的主要因素。已经证明 TSS 暴露会影响鳃的功能，但作用模式尚不清楚。斑马鱼（Danio rerio）作为机制毒理学的优秀模型正在出现，由于没有关于 TSS 对斑马鱼鳃影响的基线研究，我们测试了以下假设：环境浓度的 TSS 会损害该物种的鳃结构和功能。成年斑马鱼暴露于 0、10、100、500、1000 或 2000 mg/L TSS 中 4 天，以评估鳃形态。进一步测试了对鳃结构有影响的最小浓度，以评估关键离子转运体（包括 Na/K-ATP 酶（NKA）和液泡型 H-ATP 酶（VHA））的分布，使用共聚焦显微镜。我们的结果表明，TSS 浓度低至 100 mg/L 即可改变鳃的形态，包括丝状体厚度、鳃片厚度和上皮抬起。这也与 NKA 免疫反应性（IR）细胞计数和 100 mg/L TSS 组的强度降低有关，而 VHA-IR 细胞计数或表达以及 atp6v1a 和 atp1a1a4 的转录丰度在鳃中均无变化。这些动物的应激反应标志物，包括皮质醇、葡萄糖、乳酸和糖原的水平，在 4 天的 TSS 暴露后没有改变。总之，环境相关浓度的 TSS 可损害斑马鱼的鳃结构和功能，并有可能增强通过鳃作用的污染物的毒性。
