Male fertility can be affected by oxidative stress (OS), which occurs when an imbalance between the production of reactive oxygen species (ROS) and the body’s ability to neutralize them arises. OS can damage cells and influence sperm production. High levels of lipid peroxidation have been linked to reduced sperm motility and decreased fertilization ability. This literature review discusses the most commonly used biomarkers to measure sperm damage caused by ROS, such as the high level of OS in seminal plasma as an indicator of imbalance in antioxidant activity. The investigated biomarkers include 8-hydroxy-2-deoxyguanosine acid (8-OHdG), a marker of DNA damage caused by ROS, and F2 isoprostanoids (8-isoprostanes) produced by lipid peroxidation. Furthermore, this review focuses on recent methodologies including the NGS polymorphisms and differentially expressed gene (DEG) analysis, as well as the epigenetic mechanisms linked to ROS during spermatogenesis along with new methodologies developed to evaluate OS biomarkers. Finally, this review addresses a valuable insight into the mechanisms of male infertility provided by these advances and how they have led to new treatment possibilities. Overall, the use of biomarkers to evaluate OS in male infertility has supplied innovative diagnostic and therapeutic approaches, enhancing our understanding of male infertility mechanisms.

Polystyrene microplastics (PS-MPs) released in the environment reportedly affect the reproduction of various organisms, induced oxidative stress and apoptosis, resulting in altered sperm parameters. In this in vitro study, we tested the cytotoxicity and genotoxicity of PS-MPs by exposing human semen samples to PS-MPs levels (105 and 210 μg/mL) for 30–60–90 min. Semen parameters, genome stability, sperm DNA fragmentation (SDF) and reactive oxygen species (ROS) production were analyzed before and after exposure. Moreover, we also evaluated the expression level of spermatozoa-specific expressed genes essential for the fusion with oocyte (DCST1, DCST2, IZUMO1, SPACA6, SOF1, and TMEM95). After PS-MP exposure, semen concentration and morphology did not differ, while sperm vitality and motility decreased in a time-dependent manner. In addition, sperm agglutination was observed in the groups exposed to both PS-MPs concentrations tested. A time- and concentration-dependent reduction in genomic stability, as well as increased SDF and ROS production, was also observed. Moreover, all investigated transcripts were down-regulated after PS-MP exposure. Our results confirm the oxidative stress-mediated genotoxicity and cytotoxicity of PS-MPs on human spermatozoa. The sperm agglutination observed after treatment could be due to the aggregation of PS-MPs already adhered to the sperm membranes, hindering sperm movement and fertilizing capability. Interestingly, the downregulation of genes required for sperm–oocyte fusion, resulting from data on the in vitro experimental system, suggests that PS-MP exposure may have implications for sperm functionality. While these findings highlight potential mechanisms of sperm dysfunction, further investigations using in vivo models are needed to determine their broader biological implications. Possible environmental and working exposure to pollutants should be considered during the counselling for male infertility.

It is known that an altered redox balance interferes with normal spermatic functions. Exposure to genotoxic substances capable of producing oxidative stress (OS) can cause infertility in humans. The use of antioxidants to reduce oxidative stress contributes to the improvement in reproductive function. This study focused on an antigenotoxic evaluation of ellagic acid (EA) and ascorbic acid (AA) in combination against benzene genotoxic action on human spermatozoa in vitro. In addition to the evaluation of sperm parameters, damage in sperm genetic material and intracellular ROS quantification were assessed after AA, EA and benzene co-exposure using the TUNEL technique and DCF assay. The results showed that the combination of the two antioxidants generates a greater time-dependent antigenotoxic action, reducing both the sperm DNA fragmentation index and the oxidative stress. The genoprotective effect of AA and EA association in sperm cells lays the foundations for a more in-depth clinical study on the use of antioxidants as a therapy for male infertility.

In recent decades, intensified human activities, including industrialization and urban expansion, have given rise to significant environmental challenges, with plastic pollution emerging as a critical concern. Microplastics, particularly those derived from polystyrene (PS-MPs), are widespread in soils and oceans, posing risks to biodiversity and human health through ingestion, inhalation, and contact. This study examined the detrimental impact of PS-MPs on Zebrafish-Danio rerio (Hamilton, 1822) erythrocytes. The zebrafish (Danio rerio) is a well-established model organism in biomedical research, whereas its erythrocytes served as the cellular model investigated in this study. In vitro experiments involved exposing zebrafish erythrocytes, isolated from 25 adult zebrafish, to 105 µg/mL of PS-MPs for 30, 60 and 90 min to assess cytotoxicity, genotoxicity and oxidative stress. The results revealed a time-dependent and statistically significant reduction in erythrocyte viability (−30% to −50%), genomic stability (%GTS −20% to −40%), and a concomitant increase in DNA damage (DFI ~30–38%) and ROS production (~27–35%) compared to controls (all p ≤ 0.05). These molecular disruptions related to reduced cell viability, indicating that PS-MPs are cytotoxic and genotoxic, causing genetic damage and oxidative imbalance. The results obtained confirmed the toxicity of PS-MPs. These data suggest that PS-MPs can interfere with genetic material by inducing apoptosis through oxidative imbalance.