primarily by dead spermatozoa via an aromatic amino acidoxidase catalyzed reaction [32].Leukocytes and immature spermatozoa are the two mainsources of ROS [33]. Leukocytes particularly neutrophilsand macrophages have been associated with excessive ROSproduction and they ultimately cause sperm dysfunction[21, 34–40].Two of the main factors contributing to ROS accumulation in vitro are the absence of endogenous defensemechanism and second exposure of gametes and embryosto various manipulation techniques as well as environmentthat can lead to generation of oxidative stress [1]. Levels ofROS may rarely fluctuate within a fertile individual, but,do not affect sperm concentration and motility. This maybe due to the presence of adequate antioxidant defensemechanisms in the healthy individuals. The fluctuations inROS levels might be due to transient subclinical infection andtransient abnormalities in spermatogenesis such as, retentionof cytoplasm or periodic presence of abnormal spermatozoain semen [18].
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