Changes in Ultrastructure and Expression of Steroidogenic Factor-1 in Ovaries of ZebrafishDanio rerioExposed to Glyphosate

Abstract

Glyphosate is a broad-spectrum organophosphate (OP) herbicide, highly soluble in water, and when applied in terrestrial systems it penetrates into soil, eventually reaching the aquatic community and affecting nontarget organisms. The aim of this study was to evaluate the toxicity of glyphosate on ovaries of zebrafish (Danio rerio). Ovaries (n = 18 per triplicate) were exposed to 65 μg/L of glyphosate [N-(phosphonomethyl) glycine] for 15 d. This concentration was determined according to Resolution 357/2005/CONAMA/Brazil, which establishes the permissible concentration of glyphosate in Brazilian inland waters. Nonexposed ovaries (n = 18 per triplicate) were used as control. Subsequently, morphology and expression of steroidogenic factor-1 (SF-1) of exposed and nonexposed ovaries was determined. No apparent changes were noted in general morphology of exposed and nonexposed ovaries. However, a significant increase in diameter of oocytes was observed after exposure to glyphosate. When ovarian ultrastructure was examined the presence of concentric membranes, appearing as myelin-like structures, associated with the external membranes of mitochondria and with yolk granules was found. After glyphosate exposure, immunohistochemistry and immunoblotting revealed greater expression of SF-1 in the oocytes, which suggests a relationship between oocyte growth and SF-1 expression. These subtle adverse effects of glyphosate on oocytes raised a potential concern for fish reproduction. These results contribute to understanding glyphosate-induced toxicity to nontarget organisms, showing subcellular and molecular impairments that may affect reproduction in +female fish.

Impaired brain StAR andHSP70 gene expression in zebrafish exposed to Methyl-Parathion based insecticide

“…Brain StAR expression was also altered in Atlantic salmon exposed to ethynylestradiol (Lyssimachou and Arukwe, 2007) and nonylphenol (Arukwe, 2005). Indeed, studies on steroidogenesis disruption focused mainly on levels of steroids and receptor-mediated effects (Armiliato et al, 2014) but few data are apparently available on the effects and mechanisms of endocrine modulators Figure 2. Effects of stress (S), acute exposition to methyl-parathion-based insecticide (MPBI), or stress plus acute exposition to MPBI (MPBI + S) on StAR (A), hsp70 (B), and GR (C) expression in zebrafish brain.…”

Re-registration Challenges of Glyphosate in the European Union

“…Effects of glyphosate on somatic and ovarian growth, as well as of glyphosatebased formulations on ovarian growth and immune status of freshwater and estuarine crab species were reported (Hong et al, 2017;Avigliano et al, 2018;Canosa et al, 2018). Toxicities have extensively been reported for fish, including the zebrafish D. rerio, on which both glyphosate (Armiliato et al, 2014;Lopes et al, 2014;Uren Webster et al, 2014) and its formulated products (Bridi et al, 2017;Sulukan et al, 2017) were found to exert acute toxicity through inhibited carbonic anhydrase activity due to oxidative stress (production of reactive oxygen species), cellular apoptosis, effects on locomotor activity and aversive behavior, as well as reproduction disorders, deteriorating sperm quality, embryotoxicity malformations, and other endocrine disruption symptoms. Another study found carp (Cyprinus carpio) more sensitive to embryotoxicity of glyphosate at high concentrations (50 mg/l) than zebrafish (Fiorino et al, 2018).…”

Possible Deleterious Impact of Glyphosate and its Commercial Formulation in Reproductive Health of Fishes

“…Not only male individuals are affected but female gametocytes were also shown to have an impact after GLY exposure. In particular, the concentration of GLY used by Armiliato and colleagues (2014), which corresponds to the maximal concentration of this herbicide allowed for Brazilian inland waters, was suffi cient to induce ovarian changes in D. rerio females associated with higher steroidogenic factor 1 (SF-1) expression [19]. As for Harayashiki´s study (2013) [18] in P. vivipara, the effect of GLY on sperm quality was also investigated in D. rerio in 2014 [20].…”