Oxidative Stress Negatively Affects Human Sperm Mitochondrial Respiration

OBJECTIVE To correlate the level of oxidative stress in serum and seminal fluid and the level of sperm deoxyribonucleic acid (DNA) fragmentation with sperm mitochondrial respiratory efficiency. METHODS Sperm mitochondrial respiratory activity was evaluated with a polarographic assay of oxygen consumption carried out in hypotonically treated sperm cells. A possible relationship between sperm mitochondrial respiratory efficiency, the level of oxidative stress, and the level of sperm DNA fragmentation was investigated. RESULTS Sperm motility was positively correlated with mitochondrial respiration but negatively correlated with oxidative stress and DNA fragmentation. Interestingly, sperm mitochondrial respiratory activity was negatively affected by oxidative stress and DNA fragmentation. CONCLUSION Our data indicate that sperm mitochondrial respiration is decreased in patients with high levels of reactive oxygen species by an uncoupling between electron transport and adenosine triphosphate synthesis. This reduction in mitochondrial functionality might be 1 of the reasons responsible for the decrease in spermatozoa motility. UROLOGY 82: 78-83, 2013. (C) 2013 Elsevier Inc.