title: Studies on the toxic effects of microcystin-LR on the zebrafish (Danio rerio) under different temperatures.
abstract: It is well known that fish have stronger tolerance than mammals to microcystin (MC) exposure, and such a difference is attributed to their different core body temperatures. However, no in vivo study has been conducted to investigate the effects of temperature on MC-induced toxicity in fish, a typical poikilotherm. Tolerance and detoxification response of zebrafish treated with MC-LR were investigated under three temperatures. The LD50 values evidently increased with a decline of the temperature (547, 260 and 176 µg kg⁻¹ at 12, 22 and 32 °C, respectively), indicating stronger tolerance of the fish at lower temperatures. Changes in the transcription of glutathione S-transferase (GST) isoforms in the fish were observed, and their sensitivity of response in the transcription of GST mRNA was on the order of 12 > 32 > 22°C. We screened out several GST genes which were more delicate to solve the MC-LR exposure at different temperatures, i.e. GST rho1, al, p1 and theta1 in the 12 °C group, and GST zeta1 and p2 in the 22 and 32 °C groups. Our findings partly validate the hypothesis that high temperature enhances toxic effects of MCs on poikilotherms. Our studies also indicate that temperature-dependent toxic effects should be taken into account for field toxic assessment of microcystins in fish.
authors.affiliation: Fisheries College of Huazhong Agricultural University; Key Lab of Agricultural Animal Genetics, Breeding and Reproduction of Ministry of Education, Wuhan 430070, People's Republic of China.
authors.forename: Xuezhen
authors.initials: X
authors.lastname: Zhang
authors.forename: Wei
authors.initials: W
authors.lastname: Ji
authors.forename: Huan
authors.initials: H
authors.lastname: Zhang
authors.forename: Wei
authors.initials: W
authors.lastname: Zhang
authors.forename: Ping
authors.initials: P
authors.lastname: Xie
mesh_terms: D000818:Animals; D005982:Glutathione Transferase / Q000235:genetics / Q000378:metabolism; D007928:Lethal Dose 50; D008297:Male; D008387:Marine Toxins; D052998:Microcystins / Q000633:toxicity*; D018384:Oxidative Stress / Q000187:drug effects; D013696:Temperature; D018675:Toxicity Tests; D015027:Zebrafish
chemical_list: D008387:Marine Toxins; D052998:Microcystins; D005982:Glutathione Transferase; C057862:cyanoginosin LR