Oxidative stress response and gene expression with atrazine exposure in adult female zebrafish (Danio rerio)

Atrazine (ATZ) is the most common pesticide of freshwater ecosystems in the world. The effects of ATZ exposure on the induction of oxidative stress and the alteration of gene expression were studied in liver and ovary samples from female zebrafish (Danio rerio). Antioxidant enzyme activities (SOD and CAT), in addition to the GSH and MDA content, in the liver altered significantly; the mRNA levels for the genes encoding these antioxidant proteins, such as Cu/Zn-Sod, Mn-Sod, Cat, and Gpx, were up-regulated significantly in the liver when zebrafish were exposed to various concentrations of ATZ for 14d. However, the mRNA induction patterns were not in accordance with those of antioxidant enzyme changes in the liver and ovary. Moreover, the transcriptional expression of mitochondrial inner membrane genes related to ROS production, such as Ucp-2 and Bcl-2, were altered significantly in high ATZ treatment groups. However, the ATZ treatment did not induce any apparent changes in the transcriptional expression of CoxI, Ndi, or ATPo6, which are related to the mitochondrial respiratory chain and ATP synthesis. To our knowledge, this is the first report to study the transcriptional effects of ATZ stress on zebrafish. The information presented in this study will be helpful in fully understanding the mechanism of oxidative stress induced by ATZ in fish.