High levels of oxidation–reduction potential in frozen-thawed human semen are significantly correlated with poor post-thaw sperm quality

Abstract

This study examined the relationship between oxidation–reduction potential (ORP) in frozen-thawed semen and the post-thaw sperm parameters. Levels of ORP were measured in 25 samples from men presenting for routine infertility work-up and were expressed as millivolt (mV)/106 sperm/ml. Frozen-thawed samples were examined for post-thaw total motility (TM%), progressive motility (PM%), total sperm count (TSC) and ORP. The cryo-survival rate (CSR) was calculated as post-thaw TM/pre-freeze TM × 100. Data are provided as median and interquartile range (25th and 75th percentiles). The post-thaw TM% (10.0% [4.00%, 15.1%]), PM% (5.88% [2.97%, 9.33%]) and TSC (12.5 [10.0, 17.5] × 106 sperm) were significantly lower than the pre-freeze TM% (45.9% [32.9%, 59.1%], PM% (31.5% [24.4%, 40.0%] and TSC (120 [90, 250] ×106 sperm) (p <.001). Post-thaw ORP (2.62 [2.52, 3.13] mV/106 sperm/ml) was significantly higher than pre-freeze ORP (0.73 [0.54, 1.21] mV/106 sperm/ml; p <.001). The CSR was 21.7% (11.3%, 31.9%). The post-thaw seminal ORP was negatively correlated with post-thaw TM% (r = −.5; p =.02), PM% (r = −.41; p =.03), TSC (r = −.60; p =.03) and CSR (r = −.52; p =.01). Increased levels of ORP are significantly correlated with poor post-thaw sperm quality and CSR.