Objectives: To review the literature and provide an updated summary on the role of reactive oxygen species (ROS) in male infertility.
Methods: A review of PubMed, Cochrane review, and Web of Science databases for full-text English-language articles published between 1943 and 2017 was performed, focusing on the aetiology of ROS, physiological role of ROS on spermatic function, pathological role of ROS in infertility, evaluation of ROS, and role of antioxidants in oxidative stress.
Results: ROS play a role in spermatic function and fertilisation. The literature describes both a physiological and a pathological role of ROS in fertility. A delicate balance between ROS necessary for physiological activity and antioxidants to protect from cellular oxidative injury is essential for fertility.
Conclusion: Although elevated levels of ROS are implicated as a cause of infertility, there is no consensus on selecting patients to test for ROS, which test to perform, or if treatment for ROS can have a positive impact on infertility rates and pregnancy.
Keywords: 4-HNE, 4 hydroxy-nonenal; ATP, adenosine triphosphate; Antioxidants; CAT, catalase; ESR, electron spin resonance; Free radicals; G-6-PDH, glucose-6-phosphate dehydrogenase; GPX, glutathione peroxidase; MAGI, male accessory gland infections; MDA, malondialdehyde; Male infertility; NADH, nicotinamide adenine dinucleotide; NO, nitric oxide; ROS, reactive oxygen species; Reactive oxygen species; SOD, superoxide dismutase.