Possible mechanisms for adverse effects on zebrafish sperm and testes associated with low-level chronic PFOA exposure

Abstract

Perfluorooctanoic acid (PFOA), which is widely used during the manufacturing of fluoropolymer coatings and polytetrafluoroethylene, is now a widespread pollutant in the environment and within the human body. This study used zebrafish, an aquatic model species, to investigate how low levels of chronic PFOA exposure affect the reproductive system. The results of the experiments in which zebrafish were exposed to 414 ng/L or 4140 ng/L for 60 days showed a variety of adverse effects on testicular tissue and sperm, including dose-dependent changes in plasma estradiol and testosterone levels, various sperm malformations, decreased sperm motility and concentration, and PFOA-induced oxidative stress and testicular damage with increased rates of apoptosis. In addition, offspring of the zebrafish that had been exposed to PFOA were characterized by increased malformation and mortality. Subsequent transcriptional analyses of the male gonads revealed the significant activation of oxidative stress bioprocesses and immuno-inflammatory signaling pathways, along with the dysregulation of reproductive bioprocesses. In conclusion, low-level chronic exposure to PFOA affects both the reproductive performance of adults and the development of offspring; the mechanisms for these adverse effects involve alterations in several molecular pathways that may be involved in PFOA-induced oxidative stress and reproductive abnormalities. The presented data can be used to assess the ecotoxicity of PFOA to the male reproductive system at environmentally-relevant concentrations.