title: Apoptotic responses of zebrafish (Danio rerio) after exposure with microcystin-LR under different ambient temperatures.
abstract: Microcystins (MCs) can cause evident hepatic apoptosis. In vitro studies indicated that uptake of MC by isolated hepatocytes was dramatically reduced as ambient temperature dropped, and some studies presented a hypothesis that differences in core body temperatures in animals result in diverse uptake of MC, as well as different toxic effects. Thus far, however, few in vivo studies have been conducted to investigate the effects of temperature on MC-induced hepatocyte apoptosis in fish, a typical poikilotherm. In the present study, zebrafish were treated with MC-LR, an MC metabolite, at three water temperatures (12, 22 and 32 °C), and evident differences in apoptotic profiles were observed. Damage to liver ultrastructures revealed temperature-dependent early-stage patterns of apoptosis. Flow-cytometric analysis indicated that hepatocyte apoptotic rates varied with a temperature-dependent effect. The transcription levels of some apoptosis-related genes were determined using quantitative real-time polymerase chain reaction, and significantly elevated gene expressions of P53, Bcl-2, Bax and caspase-3 were found in the 12 and 32 °C groups. Results of the present study indicate that different ambient temperatures can lead to various toxic effects of MCs on hepatic apoptosis in fish.
authors.affiliation: Fisheries College of Huazhong Agricultural University, Key Laboratory of Agricultural Animal Genetics, Breeding and Reproduction of Ministry of Education, Wuhan, 430070, PR China.
authors.forename: Wei
authors.initials: W
authors.lastname: Ji
authors.forename: Hualei
authors.initials: H
authors.lastname: Liang
authors.forename: Wenshan
authors.initials: W
authors.lastname: Zhou
authors.forename: Xuezhen
authors.initials: X
authors.lastname: Zhang
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D053148:Caspase 3 / Q000235:genetics / Q000378:metabolism; D005786:Gene Expression Regulation; D022781:Hepatocytes / Q000187:drug effects / Q000378:metabolism; D008099:Liver / Q000187:drug effects* / Q000378:metabolism; D008387:Marine Toxins; D052998:Microcystins / Q000633:toxicity*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D013696:Temperature; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000378:metabolism; D015027:Zebrafish / Q000378:metabolism*; D029961:Zebrafish Proteins / Q000235:genetics / Q000378:metabolism; D051028:bcl-2-Associated X Protein / Q000235:genetics / Q000378:metabolism
chemical_list: D008387:Marine Toxins; D052998:Microcystins; D019253:Proto-Oncogene Proteins c-bcl-2; D016159:Tumor Suppressor Protein p53; D029961:Zebrafish Proteins; D051028:bcl-2-Associated X Protein; C571228:tp53 protein, zebrafish; D053148:Caspase 3; C057862:cyanoginosin LR