2.1.3. Leukocytes

A state of infection and/or inflammation in the male reproductive tract (i.e., testis, epididymis, seminal vesicles and/or prostate) can result in increased infiltration of leukocytes bringing with them an attendant risk of elevated ROS within an ejaculate [35]. Indeed, when appropriately stimulated, phagocytic leukocytes are capable of metabolizing oxygen to produce copious quantities of ROS in a process often referred to as a respiratory burst [36]. This microbicidal defense response is mediated by the NADPH-oxidase complex, and enhanced by the presence of cytokines, which themselves are released during inflammation [9,37]. It follows that the presence of leukocytes, and predominantly polymorphonuclear neutrophils, is recognized as a major source of ROS in human semen [37,38].
