Exploring the Epigenetic Landscape of Spermatozoa: Impact of Oxidative Stress and Antioxidant Supplementation on DNA Methylation and Hydroxymethylation.

Reproductive success is dependent on gamete integrity, and oxidative stress alters male nuclei, meaning that no DNA repair is possible due to chromatin compaction. The composition of sperm makes it highly sensitive to reactive oxygen species (ROS) but, at the same time, ROS are needed for sperm physiology. Over the past 30 years, much attention has been paid to the consequences of oxidative stress on sperm properties and the protective effects of antioxidant formulations to help fertility.

Loss of Nuclear/DNA Integrity in Mouse Epididymal Spermatozoa after Short-Term Exposure to Low Doses of Dibutyl Phthalate or Bisphenol AF and Its Mitigation by Oral Antioxidant Supplementation.

Routine exposure to chemicals omnipresent in the environment, particularly the so-called endocrine-disrupting chemicals (EDCs), has been associated with decreased sperm quality and increased anomalies in testis. The decline in semen quality and testicular abnormalities have been attributed to the disruption of endocrine signaling as well as oxidative stress. The present study set out to examine the effect of short-term exposure of two common EDCs widely used in the plastic industry: Dibutyl Phthalate (DBP) and Bisphenol AF (BPAF).

OXIDATIVE STRESS AND REPRODUCTIVE FUNCTION: Sperm telomeres, oxidative stress, and infertility.

In Brief: Oxidative stress is recognized as an underlying driving factor of both telomere dysfunction and human subfertility/infertility. This review briefly reassesses telomere integrity as a fertility biomarker before proposing a novel, mechanistic rationale for the role of oxidative stress in the seemingly paradoxical lengthening of sperm telomeres with aging.

Abstract: The maintenance of redox balance in the male reproductive tract is critical to sperm health and function.

Rapid impact of COVID-19 infection on semen quality: a case report.

A unique opportunity to conduct a longitudinal analysis of semen quality in a male subject immediately before, during and after COVID-19 infection, has revealed new insights into the impact of this virus on male reproductive function. A moderate COVID infection that did not require hospitalization resulted in a state of azoospermia that persisted for 4 weeks. Given that the duration of spermatogenesis and epididymal sperm maturation in the human is 78 days, we calculate that a viral attack on the germ line was initiated at or before the patient was symptomatic and may have been signalled by a sudden reduction in sperm count and motility, several weeks earlier.

Male Infertility and Oxidative Stress: A Focus on the Underlying Mechanisms.

Reactive oxygen species (ROS) play a critical role in defining the functional competence of human spermatozoa. When generated in moderate amounts, ROS promote sperm capacitation by facilitating cholesterol efflux from the plasma membrane, enhancing cAMP generation, inducing cytoplasmic alkalinization, increasing intracellular calcium levels, and stimulating the protein phosphorylation events that drive the attainment of a capacitated state. However, when ROS generation is excessive and/or the antioxidant defences of the reproductive system are compromised, a state of oxidative stress may be induced that disrupts the fertilizing capacity of the spermatozoa and the structural integrity of their DNA.

Apoptotic M540 bodies present in human semen interfere with flow cytometry-assisted assessment of sperm DNA fragmentation and oxidation.

Background: The use of flow cytometry (FC) to evaluate sperm DNA fragmentation via deoxynucleotidyl transferase terminal fluorescein dUTP nick-end labeling (TUNEL) has shown inconsistencies compared with conventional fluorescent microscopic analyses. It has been hypothesized that the observed discrepancies could be attributed to the presence of apoptotic bodies that can be labeled with merocyanine 540, the so-called M540 bodies. In order to verify this hypothesis and determine the accuracy of our in-house FC-assisted evaluation of spermatozoa parameters, we used FC to evaluate both the fragmentation of sperm DNA using the TUNEL assay and the oxidation of sperm DNA using the 8-OHdG assay on semen samples with or without M540 bodies.

Varicocoele and oxidative stress: New perspectives from animal and human studies.

Background: Varicocoele (VCL), one of the main causes of male subfertility, negatively affects testicular function. Due to limited access to human testicular tissue, animal model studies have been used to evaluate molecular and, recently, epigenetic changes attributed to pathophysiology induced by VCL.

Objectives: This review aims to provide an update on the latest findings regarding the link between VCL-induced biochemical stress and molecular changes in germ cells and spermatozoa.