Exposure to Thiodan® results in lipofuscin accumulation in hepatocytes of the freshwater catfish Tandanus tandanus

[摘要] ABSTRACT: We investigated the effect of time after pulse exposure to 1.0 µg l^-1 endosulfan (applied as Thiodan^®) on endosulfan residues in the liver and ultrastructural changes in the hepatocytes of the freshwater catfish Tandanustandanus. Time after exposure did not affect the mean residue level in the liver. After exposure to endosulfan, residues in the liver were 227.47 µg kg^-1 after 1 d and 282.83 µg kg^-1 after 28 d; residues in the bile were 313.97µg kg^-1 after 1 d and 334.53 µg kg^-1 after 28 d. At the end of 28 d exposure, lipofuscin was present in up to 69% of hepatocytes of fish containing residues of endosulfan, but absent from control fish. There was a statisticallysignificant increase in the percentage of pyknotic nuclei and altered rough endoplasmic reticulum 28 d after exposure. The mean percentage of cells with altered endoplasmic reticulum ranged from 12.93% (Day 1) to 7.50% (Day 28) for control fish, while forexposed fish it increased from 14.30% (Day 1) to 35.00% (Day 28). The mean percentage of cells with pyknotic nuclei increased from 1.1 to 2.1% in control fish and from 3.8 to 9.6% in exposed fish. Other ultrastructural changes included increasedultrastructural heterogeneity, progressive vacuolation and fractionation of rough endoplasmic reticulum, accumulation of lysosomes and residual bodies, intranuclear inclusions and pseudoinclusions, membrane whorls and myelinated bodies. Protractedsenescence was one of the main features of endosulfan toxicity to T. tandanus hepatocytes.

[学科分类] 生物科学（综合）

[关键词] Endosulfan;Lipofuscin;Hepatocyte