Acute Exposure of Medaka to Carcinogens: An Ultrastructural, Cytochemical and Morphometric Analysis of Liver and Kidney
Annual rept. (Final) 1 Feb 1990-31 Jan 1993
SOUTHEASTERN LOUISIANA UNIV HAMMOND DEPT OF BIOLOGICAL SCIENCES
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The primary objective of this investigation was to determine the ultrastructural effects of diethylnitrosamine DENA and trichloroethylene TCE on hepatic and renal tissues of the Japanese medaka, Oryzias latipes. The study was also designed to ascertain whether DENA can function as an inducer of cellular transformation for TCE. One group of 60 medaka was exposed to DENA 10mgL for 48hrs, rinsed and maintained in fresh water. Another group of fish was exposed continuously to TCE 10mgL until sacrificed at one of the scheduled time points. A third group was exposed to DENA 10mgL for 48hrs, rinsed in fresh water and subsequently exposed continuously to TCE 10mgL until the time of sacrifice. A control group of medaka was maintained in fresh water. The sacrifices were conducted at 8, 16, 32, and 52 weeks subsequent to the initial exposure to DENA. A majority of the fish maintained for the 52 week period died prior to sacrifice. Consequently, the remaining fish were subjected only to an ultrastructural analysis. The general cellular response to DENA appeared to be consistent among exposed medaka examined at all time points. However, the Carcinogens, Diethylnitrosamine, Trichloroethylene, Liver, Kidney, Cytochemistry, Ultrastructure, Medaka, Fish number of cells affected by the toxin and degree of severity increased for those fish sacrificed 32 and 52 weeks after exposure to DENA. The affected parenchymal cells displayed altered mitochondria, endoplasmic reticulum, and nucleoli. Spongiosis hepatis, multilocular cyst-like lesions, were detected in three livers of fish exposed to DENA.