Histological alterations in liver and testis of Astyanax aff. bimaculatus caused by acute exposition to zinc

This study investigated the effect of acute exposition to zinc (Zn) on histology of the liver and testes of yellow tail lambari (Astyanax aff. bimaculatus). The exposure consisted of six concentrations of Zn (0, 3, 5, 10, 15, and 20 mg/L) for 96 hours of exposure. Fragments of liver and testis were routinely processed and embedded in plastic resin based on glycol methacrylate. Fragments of bones, muscles, liver and testis were dehydrated and digested to quantify the absorption levels of Zn in the tissue. Acute exposure to concentrations above 10mg/L has produced structural changes in the liver and gonads. The changes found in the liver were vascular congestion; decrease of cellular volume; displacement of the hepatocyte nucleus; necrosis; disarrangement of cordon structure; leukocyte infiltrate and vacuolization. The changes found in the gonads were ruptured cyst, delayed development of germ cells, pyknotic nucleus, cell cluster, displacement of cyst wall and vacuolization. The histological changes observed were compatible with the increasing concentration of zinc in environment, compromising liver and reproductive functions, because there was an increase in relative frequency of hepatocytes and reduced sperm production

本研究探究了急性暴露于锌（Zn）对黄尾脂鲤（Astyanax aff. bimaculatus）肝脏与睾丸的组织学影响。本次暴露设置了6种锌浓度梯度（0、3、5、10、15及20 mg/L），暴露时长为96小时。研究人员对肝脏与睾丸组织片段进行常规处理，并以乙二醇甲基丙烯酸酯为基质的塑料树脂进行包埋。此外，还对骨骼、肌肉、肝脏及睾丸组织片段进行脱水与消解处理，以量化组织内锌的吸收水平。当暴露浓度高于10mg/L时，可导致肝脏与性腺出现结构改变：肝脏的病变表现为血管充血、细胞体积减小、肝细胞核移位、坏死、索状结构紊乱、白细胞浸润及空泡化；性腺的病变则包括囊肿破裂、生殖细胞发育迟缓、固缩核、细胞簇形成、囊壁移位及空泡化。本次观察到的组织学变化与环境锌浓度升高呈正相关，会损害肝脏与生殖功能，具体表现为肝细胞相对频率升高，同时精子生成量减少。