Impacts of oxidative stress on acetylcholinesterase transcription, and activity in embryos of zebrafish (Danio rerio) following Chlorpyrifos exposure.
Organophosphate pesticides cause irreversible inhibition of AChE which leads to neuronal overstimulation and death. Thus, dogma indicates that the target of OP pesticides is AChE, but many authors postulate that these compounds also disturb cellular redox processes, and change the activities of antioxidant enzymes. Interestingly, it has also been reported that oxidative stress plays also a role in the regulation and activity of AChE. The aims of this study were to determine the effects of the antioxidant, vitamin C (VC), the oxidant, t-butyl hydroperoxide (tBOOH) and the organophosphate Chlorpyrifos (CPF), on AChE gene transcription and activity in zebrafish embryos after 72h exposure. In addition, oxidative stress was evaluated by measuring antioxidant enzymes activities and transcription, and quantification of total glutathione. Apical effects on the development of zebrafish embryos were also measured. With the exception of AChE inhibition and enhanced gene expression, limited effects of CPF on oxidative stress and apical endpoints were found at this developmental stage. Addition of VC had little effect on oxidative stress or AChE, but increased pericardial area and heartbeat rate through an unknown mechanism. TBOOH diminished AChE gene expression and activity, and caused oxidative stress when administered alone. However, in combination with CPF, only reductions in AChE activity were observed with no significant changes in oxidative stress suggesting the adverse apical endpoints in the embryos may have been due to AChE inhibition by CPF rather than oxidative stress. These results give additional evidence to support the role of prooxidants in AChE activity and expression.
Faculty of Chemistry, Universidad Nacional Autónoma de México, Sisal, Yucatan, Mexico. Electronic address: grf@unam.mx.
Gabriela
G
Rodríguez-Fuentes
Faculty of Chemistry, Universidad Nacional Autónoma de México, Sisal, Yucatan, Mexico.
Fernando J
FJ
Rubio-Escalante
Faculty of Chemistry, Universidad Nacional Autónoma de México, Sisal, Yucatan, Mexico.
Elsa
E
Noreña-Barroso
Faculty of Sciences, Universidad Nacional Autónoma de México, Sisal, Yucatan, Mexico.
Karla S
KS
Escalante-Herrera
Department of Environmental Sciences, University of California Riverside, Riverside, United States.
Daniel
D
Schlenk
D000110:Acetylcholinesterase / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D004390:Chlorpyrifos / Q000633:toxicity*; D004625:Embryo, Nonmammalian / Q000187:drug effects*; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects*; D007306:Insecticides / Q000633:toxicity; D009043:Motor Activity / Q000187:drug effects*; D018384:Oxidative Stress / Q000187:drug effects*; D014874:Water Pollutants, Chemical / Q000633:toxicity; D015027:Zebrafish
D007306:Insecticides; D014874:Water Pollutants, Chemical; D000110:Acetylcholinesterase; D004390:Chlorpyrifos
Acetylcholinesterase; Chlorpyrifos; Danio rerio; Oxidative stress