PARENT SESSION
1D Bioassays for specific hazards (estrogenic effects, genotoxicity, neurotoxicity, ...)
9:00 AM to 7:00 PM, Tuesday, 08 May 2001

(T/EH088) Genotoxicity measured as DNA strand-breaks.

Maria, V.¹, Correia, A.¹, Santos, M.¹, ¹

ABSTRACT- Numerous chemical and physical agents in the environment are capable of reacting with DNA. These potential DNA-damaging substances include not only man-made compounds, but also those of natural origin. The study of xenobiotic -naphtoflavone effect (BNF) on the eel's liver and blood DNA was the objective of this experimental work. The eel's liver and blood DNA integrity was measured after 2-8 hours, 8-72 hours and 3 to 9 days exposure to 2.7, 0.9 and 0.3 M BNF. DNA damage measured as strand breaks was quantified by using the modified of the alkaline unwinding assay (adapted by Maria, V. et al, 2000, Rao, S.S. et al (1997). Environmental Toxicology and Water Quality: An International Journal, 11: 351-354). A significant decrease in liver DNA integrity appears after 6, 8, 16 and 24 hours exposure to 2.7 M BNF. The damaging effects on blood DNA significantly increased after 8 hours exposure to 2.7 M BNF. Blood DNA damage is also significantly high after 48 and 72 hours exposure to 0.9 M BNF, when compared to their control. A longer exposure length than 72 hours to 2.7 and 0.9 M BNF did not result in increased levels of blood DNA damage. The same applies to blood and liver DNA exposed to 0.3 M. The results suggest an increase in DNA integrity due to a DNA repairing system, which is either active or effective after longer exposures to 0.9 and 2.7 M BNF. The detection of DNA damage after exposure to 2.7 and 0.9 M BNF is an evidence of its potentially genotoxicity to fish.

Key words: DNA strand-breaks, genotoxicity, eel, beta-naphthoflavone