Oxidation-reduction potential as a new marker for oxidative stress: Correlation to male infertility

Abstract

Male infertility affects men worldwide. Oxidative stress (OS), characterized by an overabundance of reactive oxygen species (ROS) or a deficiency of antioxidants, is one of the major causes of male infertility. OS causes damage at the molecular level, which impairs lipids, proteins, and DNA. The cyclic cascade of redox reactions weakens sperm function which leads to poor semen parameters and eventual sterility. There is a need for advanced diagnostic tests that can quickly and accurately detect OS. Most commonly used assays can only measure single constituents of OS. However, the MiOXSYS System introduces a new strategy to detect OS by measuring the oxidation-reduction potential (ORP)--a direct evaluation of the redox balance between ROS and antioxidants. The MiOXSYS System has shown promise as a diagnostic tool in the evaluation of male infertility. This review explores the concept of ORP, details the principle of the MiOXSYS System, and summarizes the findings in clinical studies that support ORP measurement in semen.

Keywords: Diagnosis; Male infertility; Oxidative stress; Reactive oxygen species; Spermatozoa.

Fig. 1. Schematic of the physiological/pathological roles of reactive oxygen species and sources leading to increased production.

Fig. 2. Setup of the MiOXSYS (A) analyzer and sensor (B).

Fig. 3. A receiver operating characteristic curve was used to identify the static oxidation-reduction potential (mV/106 sperm/mL) criterion i.e., cutoff, sensitivity, and specificity, positive predictive value (PPV), negative predictive value (NPV), accuracy and area under the curve (AUC) that best predicted the normal and abnormal semen parameters as well as differentiated normal healthy controls from male factor infertility patients.

Fig. 4. Distribution of static oxidation-reduction potential (sORP) (mV/106 sperm/mL) in controls and patients showing the established cutoff values. Data are represented as box-plot showing median and interquartile range. The whiskers are the 95% confidence intervals.

Fig. 5. Receiver operating characteristic curve of the oxidation-reduction potential (mV/10⁶ sperm/mL) in different groups of abnormal sperm parameters: oligozoospermic group (A), asthenozoospermic group (B), and teratozoospermic group (C). Acc, accuracy; AUC, area under the curve; NPV, negative predictive value; PPV, positive predictive value; Sens, sensitivity; Spec, specificity.

Fig. 6. (A) Receiver operating characteristic curve of the oxidation-reduction potential (ORP) (mV/10⁶ sperm/mL) in detecting at least 1 sperm parameter. (B) Box-and-whisker plots showing the distributions of the ORP cutoff between normal and abnormal sperm parameters. Acc, accuracy; AUC, area under the curve; NPV, negative predictive value; PPV, positive predictive value; Sens, sensitivity; Spec, specificity.