Developmental Alterations and Oxidative Damage Induced by Environmentally Relevant Concentrations of Bisphenol a in Zebrafish Embryos (Danio Rerio)

Abstract

Bisphenol-A (BPA) is a compound widely used in the plastics industry due to its hardness and resistance to high temperatures; however, its high production and low elimination rate result in its presence in the environment. Once in the environment, BPA can enter the body of aquatic organisms via inhalation, skin absorption, ingestion, leading to different toxic responses in organisms, such as endocrine disruption and tissue alterations. Moreover, there are multiple studies on how BPA affects embryonic development; however, most of these studies have pointed out BPA is harmful to embryos but only at concentrations that are not environmentally relevant. In the present investigation, we studied the harmful effect of BPA on the growth and redox balance of  Danio rerio  embryos and how it relates to the expression of Nrf1, Nrf2, Wnt3a, Wnt8a, COX-2, Qdpra, and DKK1 genes. For this purpose,  Danio rerio  embryos were exposed to eight environmentally relevant concentrations (220, 380, 540, 700, 860, 1180, 1340, and 1500 ngL-1) of BPA for 96 hours. BPA induced several malformations on  Danio rerio  embryos, which led to their death. These malformations included developmental delay, hypopigmentation, tail malformations, pericardial edema, scoliosis, pericardial edema, etc. The values of LC50, EC50 of malformations of BPA were 1234.6 ng L -1  and 987.77 ng L -1 , respectively. Moreover, BPA got a TI value of 1.250, which indicates this compound is teratogenic. Regarding oxidative stress and gene expression, we demonstrated BPA increased the levels of hydroperoxides, protein carbonyls, lipid peroxidation, and catalase and altered the gene expression of Nrf1, Nrf2, Wnt3a, Wnt8a, COX-2, Qdpra, and DKK1b in embryos. Therefore, we can conclude that BPA affects the growth and development of  Danio rerio  embryos, and oxidative stress is involved in this toxic response.

Keywords: Bisphenol-A, emerging pollutant, oxidative status, teratogenesis, gene expression