The histopathological effects of Thiodan (R) on the liver and gut of mosquitofish, Gambusia affinis

Thiodan (R) (33.7% endosulfan), a polychlorinated cyclodiene insecticide, w as evaluated for its histopathological effects on mosquitofish, Gambusia af finis, by light microscopy. Fish were exposed to doses of 0.00 (control), 1 .00, 2.50, and 5.00 mug/L on days 7, 14, 21, and 30. No histopathological e ffects were apparent at control group. The histopathological alterations we re characterized as oedema, degeneration, accumulation of lymphocytes in th e lamina propria, disintegration of villuses, pycnotic state of nuclei, and necrosis in gut; degeneration, hypertrophy, sinusoids enlargement, hemorrh age, pycnosis position of nuclei, vacuolization of cell cytoplasm, infiltra tion of mononuclear lymphocyte, and congestion in liver. These alterations were time- and dose-dependent.