Vascular tissue is the first site of damage in the TCDD-exposed fish embryo
- Midwest Science Center, Columbia, MO (United States)
- Univ. of Missouri, Columbia, MO (United States). Biochemistry Dept.
The planar halogenated hydrocarbons (PHHs) are a group of environmental contaminants that exert adverse biological effects in most vertebrate organisms. Embryonic development is the most sensitive life stage to the effects of these compounds. The reason for the enhanced sensitivity to PHHs during early life stages is unknown. To study TCDD-induced embryotoxicity, a fish species the medaka was the organism of choice. The authors localized the initial site of tissue damage in the developing embryo and investigated the mechanism of TCDD-induced tissue damage. There were three parts to this study, (1) observation of morphological anomalies in the TCDD-treated embryo, (2) immunohistochemical detection of DNA damage in the tissues of TCDD-treated embryos, and (3) test the ability of an antioxidant to delay the onset of initial tissue damage. Morphological observations show that the first visual lesions that occur in the TCDD treated embryo occur at stage 36, about day 6 post fertilization. The lesions are localized in the cardiac vasculature. Immunohistochemical staining, using the terminal nucleotide transferase assay (TdT-assay) which detects DNA damage showed that the initial site of tissue damage was in the vasculature in the cardiac region. Tissue damage was detected in neural tissue and muscle tissue at later time points. TCDD is known to induce oxidative stress in a variety of organisms, therefore; the authors tested to see if oxidative stress may play a role in TCDD-induced embryotoxicity. The TCDD-treated embryos were cultured in the antioxidant N-acetyl cysteine (NAC) and the morphological observations and TdT-assay were repeated. They found that NAC was able to delay the onset of tissue damage and NAC was able to reduce total mortality in the embryo. The results from this study indicate that the cardiac vasculature is the initial site of tissue damage.
- OSTI ID:
- 211964
- Report Number(s):
- CONF-9511137-; ISBN 1-880611-03-1; TRN: IM9617%%280
- Resource Relation:
- Conference: 2. Society of Environmental Toxicology and Chemistry (SETAC) world conference, Vancouver (Canada), 5-9 Nov 1995; Other Information: PBD: 1995; Related Information: Is Part Of Second SETAC world congress (16. annual meeting): Abstract book. Global environmental protection: Science, politics, and common sense; PB: 378 p.
- Country of Publication:
- United States
- Language:
- English
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