P-021 Increased oxidative stress affects semen quality negatively and is associated with reduced levels of seminal glutathione
Authors: Lassen E.M , Eskildsen T.V , Fedder J 
Published: June 2022

Abstract

Study question
Do increased levels of oxidative stress (OS) and seminal antioxidant affect semen quality?

Summary answer
Increased OS measured by MiOXSYS negatively affected sperm concentration, motility, and total motile sperm count (TMSC). Reduced levels of seminal glutathione are associated with OS.

What is known already
The enzymatic seminal antioxidants superoxide dismutase (SOD) and catalase (CAT), and the non-enzymatic antioxidant glutathione possess important roles in the defense against oxidative damage and form the first line of defense against reactive oxygen species (ROS). It is known from the literature, that excessive levels of ROS are highly implicated in the pathogenesis of male infertility.
The level of oxidative stress can be estimated by MiOXSYS Analyzer (Aytu BioScience Inc.) expressing the ‘oxidative reduction potential’ (ORP). Assessing ORP is one of the latest advancements in male infertility diagnostics, providing sensitive detection of increased OS in semen.

Study design, size, duration
This correlation study aims to explore the level of OS in a small cross-section of potentially infertile Danish males. Eighty-one (81) males from the Fertility Clinic at Odense University Hospital delivered a semen sample. The level of OS was compared to semen parameters and levels of SOD, CAT, and glutathione.

Participants/materials, setting, methods
Semen samples were collected and analyzed according to 2010 WHO criteria (concentration, volume, and %motility). TMSC was included additionally. A direct measure of OS was performed on raw sperm using MiOXSYS. Three assays were applied (Sigma-Aldrich and Abcam) to measure the enzymatic activity of SOD and CAT, and the level of total glutathione in the sperm samples. Spectrophotometric analysis of the absorbance in a plate reader was used to quantify the biochemical level of antioxidants.

Main results and the role of chance
Results showed that 43.2% of all study participants had increased levels of OS. Statistical analysis revealed a significant correlation (p&lt; 0.01) between increased OS and reduced concentration, motility, and TMSC in the ejaculates. When adjusted for smoke, motility and TMSC were found to be significant (p &lt; 0.05). Adjusting for weekly alcohol intake and body mass index (BMI) did not affect the correlation. Collectively, the results demonstrated that sperm abnormalities are related to increased levels of OS, suggesting OS to be a mediator of male fertility potential.
Furthermore, a negative correlation (p&lt; 0.05) was found between the reduced level of seminal glutathione and increased levels of OS. The finding suggests that OS is increased in the spermatozoa when the level of glutathione is low. No significant correlation between OS and reduced SOD or CAT was found.
A potential inverse relationship between the effect of SOD on CAT and GSH levels was investigated, but no significant relationship was identified. There were no statistical indications that the level of SOD is associated with the levels of CAT and GSH.

Limitations, reasons for caution
Morphology was not included as a part of the WHO criteria due to time limitations. DNA fragmentation analysis was not included, but future research should be devoted to this aspect.

Wider implications of the findings
The findings support a suggestion of an association between high OS levels in semen and reduced semen quality. It was expected that at least 30% of men would show excessive OS in sperm. The study population of the Fertility-Clinic showed higher OS than what was presented in the general population.

Trial registration number
Not applicable