Physiological and Pathological Roles of Free Radicals in Male Reproduction

Abstract

Oxidative stress (OS) is a condition caused by an imbalance between reactive oxygen species (ROS) overgeneration and decreased antioxidant defense mechanisms in the cell. OS has become a prominent factor in male reproductive dysfunction as ROS cause damage to sperm DNA, lipids and proteins, alterations to critical sperm structures and signaling pathways, leading to a decreased sperm activity and fertilizing capacity. At the same time, small amounts of ROS play vital roles in events leading to sperm maturation and acquisition of functional activity, which is why a proper oxidative balance is of paramount importance for a proper male fertility. Understanding the physiological and pathological roles of ROS in male reproduction has become an essential pillar of modern andrology; however, numerous questions related to the controversial behavior of ROS in male reproductive cells and tissues still remain unanswered. This chapter aims to summarize current evidence available on the relationships between free radicals, antioxidants and male reproduction and to trigger more scientific interest, particularly with respect to the design of efficient strategies to diagnose or treat male sub-or infertility associated with OS.

Protective effects of melatonin against the toxic effects of environmental pollutants and heavy metals on testicular tissue: A systematic review and meta-analysis of animal studies

“…Environmental pollutants impair the function of male fecundity by altering hormonal, molecular, and histological characteristics. These pollutants mostly affect biomechanics through oxidative stress and increasing free radicals causing a shift in the equilibrium between the production of free-radical species and the antioxidant defense system in male reproductive cells ( 4 , 5 ).…”

Prognostic Factors Associated With Sleep Duration: Serum Pro-Oxidant/Antioxidant Balance and Superoxide Dismutase 1 as Oxidative Stress Markers and Anxiety/Depression

“…At low concentrations, free radicals are necessary for normal cell functioning. They serve numerous physiological processes, including mitosis, gametogenesis, cell signaling, and cellular response to infection and injury [25,42]. When the disturbance in pro-oxidant/ antioxidant balance (PAB) occurs in favor of the oxidants, cells may be exposed to oxidative stress.…”

“…Some stud suggested, enough sleep can increase antioxidant activity which promotes a brain protection against free radicals via a decrease in oxidant production [22]. Oxidative stress can also result in a wide range of diseases such as neurodegenerative diseases, cancer, male infertility, diabetes, autoimmune diseases, and cardiovascular disorders [4,[23][24][25][26][27]. In the past few years, numerous studies have sought to evaluate the involvement of OS in psychiatric disorders.…”

Spermatozoa under Oxidative Stress: Risk or Benefit?

“…Most often oxidative damage is caused by free radicalsreactive oxygen (ROS) or nitrogen species (RNS) although other groups of radical molecules have also been studied. Free radicals can carry a positive, negative or a neutral charge depending on how they entered the reactive state -through gain or loss of an electron [56]:…”