title: Cardiac toxicity by sublethal 2,3,7,8-tetrachlorodibenzo-p-dioxin correlates with its anti-proliferation effect on cardiomyocytes in zebrafish embryos.
abstract: The cardiac toxicity of zebrafish embryos in response to the lethal dose of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) has been well characterized. Dioxin contamination levels in nature are usually lower, however, and sublethal TCDD toxicity is less investigated. The present study found that the nonlethal doses of TCDD for 72-h-postfertilization (hpf) zebrafish embryos were 25 pg/mL and lower. For the present study, sublethal TCDD concentrations of 10 pg/mL and 25 pg/mL were selected, and their toxicity was then characterized. The results showed that embryos still exhibited acute and subchronic cardiac toxicity at these 2 dosages. The stroke volume and cardiac output of these embryos significantly declined early until 8 d postexposure. Embryos' heart size became smaller, and the hearts contained fewer cardiomyocytes per heart, with decreased cardiomyocyte proliferation. Apoptosis was not detected either in the TCDD-treated or the control hearts. Real-time polymerase chain reaction (PCR) revealed that the transcription of a battery of cell-cycle-related genes was suppressed within the sublethal TCDD-treated heart. In contrast, embryonic jaw development seemed not to be affected. The present study suggests that dioxin contamination, even at lower levels, might lead to cardiac toxicity in fish embryos. Such cardiac toxicity presents as disrupted normal heart function, originating from the anti-proliferative effect of sublethal TCDD on cardiomyocytes.
authors.affiliation: Department of Biotechnology, Institute of Life Sciences, Fujian Normal University, Fuzhou, Fujian, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Chen
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D066126:Cardiotoxicity / Q000196:embryology* / Q000473:pathology; D002356:Cartilage / Q000187:drug effects / Q000196:embryology; D002452:Cell Count; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism; D049109:Cell Proliferation / Q000187:drug effects; D015536:Down-Regulation / Q000187:drug effects / Q000235:genetics; D004625:Embryo, Nonmammalian / Q000187:drug effects* / Q000473:pathology*; D047108:Embryonic Development / Q000187:drug effects / Q000235:genetics; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects; D007568:Jaw / Q000187:drug effects / Q000196:embryology; D009206:Myocardium / Q000378:metabolism / Q000473:pathology; D032383:Myocytes, Cardiac / Q000187:drug effects* / Q000473:pathology*; D009929:Organ Size / Q000187:drug effects; D000072317:Polychlorinated Dibenzodioxins / Q000633:toxicity*; D060888:Real-Time Polymerase Chain Reaction; D016019:Survival Analysis; D015027:Zebrafish / Q000196:embryology*; D029961:Zebrafish Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D018797:Cell Cycle Proteins; D000072317:Polychlorinated Dibenzodioxins; D029961:Zebrafish Proteins
keywords: Apoptosis; Cardiac toxicity; Cardiomyocyte proliferation; Sublethal TCDD; Zebrafish embryos