Histological and Transcriptomic Changes in Male Zebrafish Testes Due to Early Life Exposure to Low Level 2,3,7,8-Tetrachlorodibenzo-p-Dioxin.
We have shown that zebrafish (Danio rerio) are an excellent model for evaluating the link between early life stage exposure to environmental chemicals and disease in adulthood and subsequent unexposed generations. Previously, we used this model to identify transgenerational effects of dioxin (2,3,7,8-tetrachlorodibenzo-p-dioxin [TCDD]) on skeletal development, sex ratio, and reproductive capacity. Transgenerational inheritance of TCDD toxicity, notably decreased reproductive capacity, appears to be mediated through the male germ line. Thus, we examine testicular tissue for structural and gene expression changes using histology, microarray, and quantitative reverse transcription polymerase chain reaction (qRT-PCR). Histological analysis revealed decreased spermatozoa with concurrent increase in spermatogonia, and decreased germinal epithelium thickness in TCDD-exposed males compared with controls. We also identified altered expression of genes associated with testis development, steroidogenesis, spermatogenesis, hormone metabolism, and xenobiotic response. Altered genes are in pathways involving lipid metabolism, molecular transport, small molecule biochemistry, cell morphology, and metabolism of vitamins and minerals. These data will inform future investigations to elucidate the mechanism of adult-onset and transgenerational infertility due to TCDD exposure in zebrafish.
1 Fisheries Management, Fish, Wildlife, and Parks Division, Wisconsin Department of Natural Resources , Madison, Wisconsin.
Bridget B
BB
Baker
2 Molecular and Environmental Toxicology Center, University of Wisconsin-Madison , Madison, Wisconsin.
Jeremiah S
JS
Yee
3 Department of Pharmacology, School of Medicine, Wayne State University , Detroit, Michigan.
Danielle N
DN
Meyer
4 School of Pharmacy, University of Wisconsin-Madison , Madison, Wisconsin.
Doris
D
Yang
2 Molecular and Environmental Toxicology Center, University of Wisconsin-Madison , Madison, Wisconsin.|3 Department of Pharmacology, School of Medicine, Wayne State University , Detroit, Michigan.|4 School of Pharmacy, University of Wisconsin-Madison , Madison, Wisconsin.|5 Institute of Environmental Health Sciences, Center for Urban Responses to Environmental Stressors, Wayne State University , Detroit, Michigan.
Tracie R
TR
Baker
D000818:Animals; D015870:Gene Expression / Q000187:drug effects*; D008297:Male; D000072317:Polychlorinated Dibenzodioxins / Q000633:toxicity*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013737:Testis / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D014874:Water Pollutants, Chemical / Q000633:toxicity*; D015027:Zebrafish / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*
D000072317:Polychlorinated Dibenzodioxins; D014874:Water Pollutants, Chemical