Characterizing semen parameters and their association with reactive oxygen species in infertile men

Abstract

Background: A routine semen analysis is a first step in the laboratory evaluation of the infertile male. In addition, other tests such as measurement of reactive oxygen species can provide additional information regarding the etiology of male infertility. The objective of this study was to investigate the association of semen parameters with reactive oxygen species (ROS) in two groups: healthy donors of unproven and proven fertility and infertile men. In addition, we sought to establish an ROS cutoff value in seminal plasma at which a patient may be predicted to be infertile.

Methods: Seminal ejaculates from 318 infertile patients and 56 donors, including those with proven fertility were examined for semen parameters and ROS levels. Correlations were determined between traditional semen parameters and levels of ROS among the study participants. ROS levels were measured using chemiluminescence assay. Receiver operating characteristic curves were obtained to calculate a cutoff value for these tests.

Results: Proven Donors (n = 28) and Proven Donors within the past 2 years (n = 16) showed significantly better semen parameters than All Patients group (n = 318). Significantly lower ROS levels were seen in the two Proven Donor groups compared with All Patients. The cutoff value of ROS in Proven Donors was determined to be 91.9 RLU/s with a specificity of 68.8% and a sensitivity of 93.8%.

Conclusions: Infertile men, irrespective of their clinical diagnoses, have reduced semen parameters and elevated ROS levels compared to proven fertile men who have established a pregnancy recently or in the past. Reactive oxygen species are negatively correlated with traditional semen parameters such as concentration, motility and morphology. Measuring ROS levels in the seminal ejaculates provides clinically-relevant information to clinicians.

Figure 1

Box Plots for semen parameters of Donors vs. Infertile Patients. Box plots comparing between All Donors, Proven Donors and Proven Donors <2 years and All Patients for concentration (A-C); motility (D-F) and morphology (G-I) and ROS levels in J: All Donors and All Patients; K: Proven Donors and All Patients; L: Proven Donors <2 years and All Patients. The box plots show the width and the whiskers. The width of the box is proportional to the size of the group. The bottom and the top of the box represent the 25th and 75^th percentile. The band in the box is the median. The whiskers represent the standard deviation. These box plots show that concentration, motility, and morphology vary between 3 groups of donors and patients

Figure 2

Receiver operating characteristic curves showing cutoff value, sensitivity and specificity for All Donors and All Patients for A: concentration (AUC = 0.640); B: motility (AUC = 0.602) and C: morphology (AUC = 0.775); Proven Donors and All Patients for D: concentration (AUC = 0.674); E: motility (AUC = 0.562) and F: morphology (AUC = 0.765) and All Proven Donors <2 years established pregnancy in the last 2 years and All Patients. G: concentration (AUC = 0.728); H: motility (AUC = 0.562) and I: morphology (AUC = 0.723).

Figure 3

Receiver operating characteristic curves for ROS showing cutoff value, sensitivity and specificity. A: All Donors and All Patients; B: Proven Donors and All Patients; C: Proven Donors <2 years of established pregnancy and All Patients. The area under curve for All Donors vs. All Patients was 0.683; Proven Donors vs. All Patients was 0.783 and Proven Donors <2 years of established pregnancy and All Patients was 0.785.