McNeil Paul L, Nebot Carolina, Cepeda Alberto, Sloman Katherine A
Institute of Biomedical and Environmental Health Research, School of Science and Sport, University of the West of Scotland, Paisley, UK.
Department of Analytical Chemistry, Nutrition and Bromatology, Faculty of Veterinary Medicine, University of Santiago de Compostela, Lugo, Spain.
Environ Pollut. 2016 Nov;218:981-987. doi: 10.1016/j.envpol.2016.08.048. Epub 2016 Sep 7.
The development of the eye in vertebrates is dependent upon glucocorticoid signalling, however, specific components of the eye are sensitive to synthetic glucocorticoids. The presence of synthetic glucocorticoids within the aquatic environment may therefore have important consequences for fish, which are heavily reliant upon vision for mediating several key behaviours. The potential ethological impact of synthetic glucocorticoid oculotoxicity however has yet to be studied. Physiological and behavioural responses which are dependent upon vision were selected to investigate the possible toxicity of prednisolone, a commonly occurring synthetic glucocorticoid within the environment, during early life stages of zebrafish. Although exposure to prednisolone did not alter the morphology of the external eye, aggregation of melanin within the skin in response to increasing light levels was impeded and embryos exposed to prednisolone (10 μg/l) maintained a darkened phenotype. Exposure to prednisolone also increased the preference of embryos for a dark environment within a light dark box test in a concentration dependent manner. However the ability of embryos to detect motion appeared unaffected by prednisolone. Therefore, while significant effects were detected in several processes mediated by vision, changes occurred in a manner which suggest that vision was in itself unaffected by prednisolone. Neurological and endocrinological changes during early ontogeny are considered as likely candidates for future investigation.
脊椎动物眼睛的发育依赖于糖皮质激素信号传导，然而，眼睛的特定组成部分对合成糖皮质激素敏感。因此，水生环境中合成糖皮质激素的存在可能对鱼类产生重要影响，鱼类严重依赖视觉来调节多种关键行为。然而，合成糖皮质激素眼毒性的潜在行为学影响尚未得到研究。在斑马鱼的早期生命阶段，选择依赖视觉的生理和行为反应来研究泼尼松龙（一种环境中常见的合成糖皮质激素）的可能毒性。虽然暴露于泼尼松龙并未改变眼睛外部形态，但随着光照强度增加，皮肤内黑色素的聚集受到阻碍，暴露于泼尼松龙（10μg/l）的胚胎保持深色表型。在明暗箱试验中，暴露于泼尼松龙还以浓度依赖的方式增加了胚胎对黑暗环境的偏好。然而，胚胎检测运动的能力似乎不受泼尼松龙影响。因此，虽然在由视觉介导的几个过程中检测到显著影响，但变化的发生方式表明视觉本身不受泼尼松龙影响。早期个体发育过程中的神经和内分泌变化被认为是未来研究的可能对象。
