Atrazine (ATZ) is among the most widely used herbicides in the world, and yet it has a potential to contaminate aquatic environments due to pesticide leaching from agricultural areas. In the Neotropical region, studies about the effects of this herbicide in native aquatic wildlife is scarce.Our study aimed at investigating the effects of a 30-day exposure to a commercial atrazine formulation on oxidative stress parameters, histopathology in testis and liver, and hormone levels in males and female of yellow-tailed tetra fish (Astyanax altiparanae). Adults were exposed to low but environmentally relevant concentrations of atrazine as follows: 0 (CTL-control), 0.5 (ATZ0.5), 1 (ATZ1), 2 (ATZ2) and 10 (ATZ10) μg/L. Our results showed decreased GST activity in gills in all groups of exposed animals and increased CAT activity in gills from the ATZ10 group. In the liver, there was an increase in lipid peroxidation in fish from ATZ1 and ATZ2 groups. Histological analysis of the liver showed increased percentage of sinusoid capillaries in ATZ2 fish, increased vascular congestion in ATZ1 and increased leukocyte infiltration in the ATZ10 group. Hepatocyte diameter analysis revealed a decrease in cell size in all groups exposed to ATZ, and a decrease in hepatocyte nucleus diameter in ATZ1, ATZ2 and ATZ10 groups. Endocrine parameters did not show significant changes following ATZ exposure, although an increase of triiodothyronine/thyroxine (T₃/T₄) ratio was observed in ATZ2 fish. Our results provide evidence that even low, environmentally relevant concentrations of ATZ produced oxidative damage and histological alterations in adult yellow-tailed tetra.

阿特拉津（ATZ）是世界上使用最广泛的除草剂之一，但由于农药从农业地区浸出，它有可能污染水生环境。在新热带地区，关于这种除草剂对本地水生野生生物影响的研究很少，我们的研究旨在调查暴露于商业阿特拉津制剂30天对氧化应激参数，睾丸和肝脏的组织病理学以及激素的影响。尾四足鱼（Astyanax altiparanae）在雄性和雌性中的水平）。成年人暴露于低浓度但与环境有关的阿特拉津，浓度如下：0（CTL对照），0.5（ATZ0.5），1（ATZ1），2（ATZ2）和10（ATZ10）μg/ L。我们的结果表明，所有暴露动物组的g中GST活性均降低，而ATZ10组的g中CAT活性提高。在肝脏中，ATZ1和ATZ2组的鱼体内脂质过氧化作用增加。肝脏的组织学分析显示，ATZ2鱼的窦状毛细血管百分比增加，ATZ1的血管充血增加，ATZ10组的白细胞浸润增加。肝细胞直径分析显示，暴露于ATZ的所有组的细胞大小均减小，而ATZ1，ATZ2和ATZ10组的肝细胞核直径均减小。暴露ATZ后，内分泌参数未显示明显变化，在ATZ2鱼中观察到₃ / T ₄）比率。我们的结果提供了证据，即使低，与环境相关的ATZ浓度也会在成年的黄尾四方动物中产生氧化损伤和组织学改变。