Pyrethroids cypermethrin, deltamethrin and fenvalerate have different effects on in vitro maturation of pig oocytes at different stages of growth

Abstract

Pesticides can significantly harm reproduction in animals and people. Pyrethroids are often used as insecticides, and their toxicity for mammals is considered to be low. However, cypermethrin, deltamethrin and fenvalerate -as potent specific inhibitors of protein phosphatase calcineurin -can influence the meiosis of mammalian oocytes. The objective of this study was to evaluate the effects of these pyrethroids on the in vitro maturation of pig oocytes at different levels of meiotic competence. Under the tested concentrations, cypermethrin, deltamethrin and fenvalerate neither had a significant effect on the viability of oocytes nor did they induce significant degeneration of oocytes. However, these pyrethroids significantly affected meiotic maturation. The effects depended on the stage of meiotic competence of the oocytes. Maturation of growing pig oocytes with partial meiotic competence was induced. On the other hand, in fully grown pig oocytes with full meiotic competence, maturation in vitro was delayed. The specificity of these effects was further supported by the same effect of non-pyrethroidal inhibitors of calcineurin -cyclosporin A or hymenistatin I -on the maturation of oocytes with different levels of meiotic competence. However, pyrethroids, which do not inhibit calcineurin -allethrin or permethrin -had no effect on pig oocyte maturation. We demonstrated a significant effect of pyrethroids on the maturation of mammalian oocytes under in vitro conditions. This indicates that exposure to these substances could affect the fertility of people or animals.

Story of Bisphenol S – Steps from Bad to Worse

“…It now appears that pyrethroids can also have a negative impact on mammals including man. In mammals, pyrethroids affect the functions of the brain (Viel et al, 2015) and reproductive organs (Petr et al, 2013). There are some "happy-end stories" in the substitution of a detrimental chemical with a harmless one, e.g.…”

Inhibition of calcineurin by FK506 stimulates germinal vesicle breakdown of mouse oocytes in hypoxanthine-supplemented medium

“…Recently, it is reported that both calcineurin subunit A and B are localized in porcine oocytes during growth and meiotic maturation ( Tumova et al, 2013 ). Two potent specific inhibitors of calcineurin has been found which could influence the meiosis of pig oocytes as well as enhance the maturation of growing pig oocytes with partial meiotic competence and delay the maturation of fully grown pig oocytes with full meiotic competence ( Petr et al, 2013 ). While, other study shows that calcineurin catalytic subunit is undetectable in M II mouse oocytes and calcineurin inhibitors (CSA, FK506 or CN-inhibitory peptide) cannot prevent meiotic exit ( Suzuki et al, 2010 ).…”

Scrotal circumference and body measurements of Yankasa rams following exposure to Cypermethrin

“…The effect of pyrethroid exposure in female animals has been well elaborated by many researchers. (Liu et al, 2011;Petr et al, 2013;Gill et al, 2011;Lemos et al, 2011;Guerra et al, 2011).…”