title: In vitro and in vivo acute toxicity of fenpyroximate to flounder Paralichthys olivaceus and its gill cell line FG.
abstract: Fenpyroximate, an acaricide, is widely used in the prevention of acarids (mites) in plants. In this study, the in vitro and in vivo acute toxicity of fenpyroximate was examined using the marine flounder Paralichthys olivaceus and its gill cell line (FG). The 48h-IC(50) (95% confidence limits) values of fenpyroximate in the FG cells were 890 (790-990)nM, 950 (881-1019)nM and 1250 (1159-1341)nM, and 96h-IC(50) (95% confidence limits) were 480 (388-572)nM, 490 (454-526)nM and 510 (469-551)nM, for methyl thiazolyl tetrazolium (MTT) assay, neutral red (NR) uptake and cell protein assay, respectively. The 48h- and 96h-LC(50) (95% confidence limits) values of fenpyroximate in living flounders were 28.84 (14.28-58.26)nM and 11.74 (6.06-22.8)nM, respectively. This indicated that fenpyroximate was highly toxic to both flounders and FG cells. Moreover, comparisons of the ratios of average 48h-IC(50) to 48h-LC(50) and average 96h-IC(50) to 96h-LC(50) showed that the length of exposure time did not significantly affect the correlation between the FG cells and living flounders in the acute toxicity estimation of fenpyroximate provided the selected exposure time is the same. Thus, we suggest that FG cells could be a good bioassay system in rapid estimation of the corresponding LC(50) values of pollutants to living fish, instead of whole living fish. Histopathological examinations showed that liver and gill were the major target organs of fenpyroximate, especially the damage of gill tissues may account much for the high lethality of exposed flounders. Consistent with the histopathological observations, analysis of the activities of two key detoxification metabolism-related enzymes, glutathione S-transferase (GST) and cytochrome P4501A1 (CYP1A1)-dependent ethoxyresorufin-O-deethylase (EROD), in the liver and gill tissues of exposed flounders indicated that liver has much higher detoxification capacity than gills, and this contributes to the higher tolerance of liver to the toxicity of fenpyroximate in the exposed flounders. Fenpyroximate can initially induce a quick and significant increase of the activities of the antioxidant enzymes superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPX) in all the exposed FG cells, and liver and gill tissues of exposed flounders. Upon continuation of the exposure the enzyme activities were inhibited, implying the occurrence of oxidative stress in the exposed fish cells and the possible interruption of the mitochondrial respiratory chain which involves redox reactions by fenpyroximate.
authors.affiliation: Department of Marine Biology, Ocean University of China, Qingdao 266003, PR China.
authors.forename: Na
authors.initials: N
authors.lastname: Na
authors.forename: Huarong
authors.initials: H
authors.lastname: Guo
authors.forename: Shicui
authors.initials: S
authors.lastname: Zhang
authors.forename: Zhaojie
authors.initials: Z
authors.lastname: Li
authors.forename: Licheng
authors.initials: L
authors.lastname: Yin
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000378:metabolism; D001565:Benzoates / Q000633:toxicity*; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D019363:Cytochrome P-450 CYP1A1 / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D042967:Electron Transport Complex I / Q000037:antagonists & inhibitors; D005432:Flounder / Q000254:growth & development; D005880:Gills / Q000166:cytology / Q000187:drug effects* / Q000201:enzymology / Q000473:pathology; D005982:Glutathione Transferase / Q000378:metabolism; D007306:Insecticides / Q000633:toxicity*; D007668:Kidney / Q000187:drug effects* / Q000201:enzymology / Q000473:pathology; D007928:Lethal Dose 50; D008099:Liver / Q000187:drug effects* / Q000201:enzymology / Q000473:pathology; D011720:Pyrazoles / Q000633:toxicity*; D012044:Regression Analysis
chemical_list: D000975:Antioxidants; D001565:Benzoates; D007306:Insecticides; D011720:Pyrazoles; C415144:fenpyroximate; D019363:Cytochrome P-450 CYP1A1; D005982:Glutathione Transferase; D042967:Electron Transport Complex I