Markers of oxidative stress and sperm chromatin integrity

Oxidative stress (OS) is an imbalance between the amount of reactive oxygen species (ROS) produced and the ability of the antioxidants to scavenge these. OS has been established as a major etiological cause of male infertility. High levels of ROS are harmful and cause damage to sperm nuclear DNA. Evaluation of OS-related damage to spermatozoa is therefore highly relevant in assisted reproductive techniques (ART) such as intracytoplasmic sperm injection (ICSI). ICSI is an effective therapy for severe male factor infertility that bypasses the majority of reproductive tract deficiencies. Despite the controversial findings in the existing literature, there is now enough evidence to show that sperm DNA damage is detrimental to reproductive outcomes. In addition to impairment of fertility, such damage might increase the transmission of genetic diseases to the offspring. Standardization of protocols to assess ROS, antioxidant status, and DNA damage is very important for implementation of these tests in clinical practice. Estimation of seminal ROS levels and extent of sperm DNA damage, especially in an infertile male, may help develop new therapeutic strategies and improve the success of ART.