title: Anti-oxidative functions of mt2 and smtB mRNA expression in the gills and brain of zebrafish (Danio rerio) upon cadmium exposure.
abstract: There were not any past studies about metallothionein isoforms (smtB and mt2) having anti-oxidative functions on zebrafish after Cd2+exposure. On the other hand, the anti-oxidative enzymatic factors such as superoxide dismutase (sod), glutathione peroxidase (gpx1a), and catalase (cat) are used as references to investigate whether the smtB and mt2 have anti-oxidative responses on the gills and brain of zebrafish after 1-6 h of 0 and 1.78 μM Cd2+exposure. The anti-oxidative system such as sod, cat, and gpx1a mRNA expressions demonstrated a cascade response upon Cd2+-induced oxidative stress in the present study. Interestingly, the smtB mRNA expression levels increased by 3.2- to 6.1-fold, and mt2 raised by 4.1- to 11.3-fold in gills at 1 and 3 h after exposure to Cd2+, respectively. On the other hand, the smtB mRNA levels increased by 10.6- to 58.6-fold, but mt2 mRNA levels increased by 2.3- to 11.1-fold in brain at 1 and 3 h after exposure to Cd2+, respectively. In addition, both tissues showed increased apoptosis levels at 3 h, and recovery after 6 h of Cd2+exposure. From the results, we suggest that both mt2 and smtB play a role in anti-oxidation responses within 6 h after exposure to Cd2+. In conclusion, the smtB mRNA levels have a higher response than mt2 in the brain, but both mRNA expressions appear to have a similar pattern in the gill. We suggest that smtB plays an important role to defend oxidative stress in the brain of adult zebrafish upon acute Cd2+exposure.
authors.affiliation: Department of Aquatic Biosciences, National Chiayi University, 300 University Road, Chiayi, 600, Taiwan. sumei@mail.ncyu.edu.tw.
authors.forename: Su Mei
authors.initials: SM
authors.lastname: Wu
authors.affiliation: Department of Aquatic Biosciences, National Chiayi University, 300 University Road, Chiayi, 600, Taiwan.
authors.forename: Li-Hsin
authors.initials: LH
authors.lastname: Shu
authors.affiliation: Department of Aquatic Biosciences, National Chiayi University, 300 University Road, Chiayi, 600, Taiwan.
authors.forename: Jia-Hao
authors.initials: JH
authors.lastname: Liu
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D001921:Brain / Q000187:drug effects* / Q000378:metabolism; D002104:Cadmium / Q000633:toxicity*; D002374:Catalase / Q000235:genetics; D015870:Gene Expression; D005880:Gills / Q000187:drug effects* / Q000378:metabolism; D005979:Glutathione Peroxidase / Q000235:genetics; D008297:Male; D008668:Metallothionein / Q000235:genetics*; D020033:Protein Isoforms / Q000235:genetics; D012333:RNA, Messenger / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D013482:Superoxide Dismutase / Q000235:genetics; D014874:Water Pollutants, Chemical / Q000633:toxicity; D015027:Zebrafish / Q000235:genetics* / Q000378:metabolism; D029961:Zebrafish Proteins / Q000235:genetics* / Q000378:metabolism
chemical_list: D020033:Protein Isoforms; D012333:RNA, Messenger; D017382:Reactive Oxygen Species; D014874:Water Pollutants, Chemical; D029961:Zebrafish Proteins; D002104:Cadmium; D008668:Metallothionein; D002374:Catalase; D005979:Glutathione Peroxidase; D013482:Superoxide Dismutase
keywords: Apoptosis; Cadmium; Metallothionein; Reactive oxygen species; Zebrafish