Environmental Cues and Sperm Quality

The increase in the occurrence of defective spermatogenesis and other important fertility issues in males evidenced over the past few decades have prompted the research on the possible contribution of environmental factors to this adverse trend. Environmental contaminants may act through different molecular targets in male reproductive system, being able to disrupt the functioning of reproductive axis and, consequently, testicular physiology and metabolism. In addition, endocrine disruptors and environmental compounds that favor adipogenesis, namely obesogens, are also related to the imbalance of tightly regulated metabolic processes and to a host of other adverse reproductive outcomes. Such effects may result from an exposure during gestation, prepubertal age or adulthood, emphasizing the importance of different environmental impacts throughout the life course. Environmental contaminants may also promote disturbances in the metabolic performance of the following generations, through epigenetic modifications passed by male gametes. As society increasingly introduces new potentially toxic substances into daily life, unveiling the molecular pathways by which environmental contaminants induce toxicity that may end-up in epigenetic modifications is imperative. Otherwise, a transgenerational susceptibility to metabolic diseases may be favored. Herein, we discuss the suggested molecular targets and potential mechanisms for environmental contaminants action and the subsequent effects of exposure during different life stages of the male. We also present an up-todate overview about the impact of endocrine disruptors and obesogens on male reproductive health, as well as the epigenetic modifications induced by these environmental cues.

Keywords: Environmental contaminants, Endocrine disruptors, Epigenetic modifications, Glucose metabolism, Lipid metabolism, Male fertility, Molecular toxicology, Obesogens, Spermatogenesis, Sertoli cells, Sperm quality, Transgenerational effects.