Long-term toxic impact of 2,3,7,8-tetrachlorodibenzo-p-dioxin on the reproduction, sexual differentiation, and development of different life stages of Gobiocypris rarus and Daphnia magna.
The sexual ratio of Gobiocypris rarus exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and 17 beta-estradiol from embryo to sexually mature revealed feminization and overdevelopment of connective tissue in male fish gonad in 2--30 pg/L TCDD concentration range. Daphnia magna was not sensitive to the high dose of TCDD (0.1--1000 ng/ml), but the reproduction of D. magna treated with TCDD decreased after the 8th day. 7-Ethoxyresorufin-O-deethylase (EROD) activities in newly fertilized eggs of G. rarus exposed to TCDD dosage groups (1000--100,000 pg/L) were significantly induced and increased with TCDD concentrations at the early life stage, while no difference was found between low TCDD dosage groups (<100 pg/L), but a good relationship between the EROD activity and the TCDD concentration was observed during a long-term developmental stage. There was a pericardial edema formed in a 2-week yolk-sac at the concentration of 1000 pg/L TCDD. But in the exposure group (2 pg/L TCDD for 120 days), the cell nuclei of hepatocytes was far from the center and packed toward the cell membrane; the cristae of most mitochondria in the cell dropped and collapsed; the rough endoplasmic reticulum broke into fragments; and numerous lipid droplets formed in the cell.
Wu
W Z
WZ
State Key Laboratory for Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, P. R. China. wuwz@ihb.ac.cn
Li
W
W
Xu
Y
Y
Wang
J W
JW
D000818:Animals; D019363:Cytochrome P-450 CYP1A1 / Q000096:biosynthesis; D003621:Daphnia / Q000187:drug effects* / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004625:Embryo, Nonmammalian / Q000187:drug effects / Q000196:embryology; D004785:Environmental Pollutants / Q000633:toxicity*; D004790:Enzyme Induction; D004958:Estradiol / Q000633:toxicity; D005260:Female; D005399:Fishes; D022781:Hepatocytes / Q000187:drug effects / Q000648:ultrastructure; D008018:Life Cycle Stages / Q000187:drug effects*; D008297:Male; D000072317:Polychlorinated Dibenzodioxins / Q000493:pharmacokinetics / Q000633:toxicity*; D012098:Reproduction / Q000187:drug effects*; D012733:Sex Differentiation / Q000187:drug effects*; D012744:Sex Ratio; D013737:Testis / Q000187:drug effects / Q000473:pathology
D004785:Environmental Pollutants; D000072317:Polychlorinated Dibenzodioxins; D004958:Estradiol; D019363:Cytochrome P-450 CYP1A1