Mela Maritana, Neto Francisco Filipak, Yamamoto Flávia Yoshie, Almeida Ronaldo, Grötzner Sonia Regina, Ventura Dora Fix, de Oliveira Ribeiro Ciro Alberto
Departamento de Psicologia Experimental, Instituto de Psicologia, Universidade de São Paulo, São Paulo, SP, Brazil,
Fish Physiol Biochem. 2014 Feb;40(1):245-56. doi: 10.1007/s10695-013-9840-4. Epub 2013 Aug 8.
In the present study, we investigated the mercury distribution, mercury bioaccumulation, and oxidative parameters in the Neotropical fish Hoplias malabaricus after trophic exposure. Forty-three individuals were distributed into three groups (two exposed and one control) and trophically exposed to fourteen doses of methylmercury each 5 days, totalizing the doses of 1.05 μg g⁻¹ (M1.05) and 10.5 μg g⁻¹ (M10.5 group). Autometallography technique revealed the presence of mercury in the intestinal epithelia, hepatocytes, and renal tubule cells. Mercury distribution was dose-dependent in the three organs: intestine, liver, and kidney. Reduced glutathione concentration, glutathione peroxidase, catalase, and glutathione S-transferase significantly decreased in the liver of M1.05, but glutathione reductase increased and lipid peroxidation levels were not altered. In the M10.5, most biomarkers were not altered; only catalase activity decreased. Hepatic and muscle mercury bioaccumulation was dose-dependent, but was not influenced by fish sex. The mercury localization and bioaccumulation corroborates some histopathological findings in this fish species (previously verified by Mela et al. in Ecotoxicol Environ Saf 68:426-435, 2007). However, the results of redox biomarkers did not explain histopathological findings previously reported in M10.5. Thus, fish accommodation to the stressor may reestablish antioxidant status at the highest dose, but not avoid cell injury.
在本研究中，我们调查了新热带鱼马拉巴锯脂鲤在经营养暴露后体内汞的分布、汞生物累积及氧化参数。43条鱼被分为三组（两组暴露组和一组对照组），每5天对其进行14次甲基汞营养暴露，总计剂量分别为1.05μg g⁻¹（M1.05组）和10.5μg g⁻¹（M10.5组）。自动金相技术揭示了肠道上皮、肝细胞和肾小管细胞中汞的存在。汞在肠道、肝脏和肾脏这三个器官中的分布呈剂量依赖性。M1.05组肝脏中的还原型谷胱甘肽浓度、谷胱甘肽过氧化物酶、过氧化氢酶和谷胱甘肽S -转移酶显著降低，但谷胱甘肽还原酶增加，脂质过氧化水平未改变。在M10.5组中，大多数生物标志物未改变；只有过氧化氢酶活性降低。肝脏和肌肉中的汞生物累积呈剂量依赖性，但不受鱼的性别的影响。汞的定位和生物累积与该鱼类的一些组织病理学发现相符（此前Mela等人在《生态毒理学与环境安全》68:426 - 435, 2007中已证实）。然而，氧化还原生物标志物的结果并不能解释先前在M10.5组中报道的组织病理学发现。因此，鱼类对压力源的适应可能会在最高剂量时重新建立抗氧化状态，但无法避免细胞损伤。
