Physiology of reactive oxygen species
ROS are considered to be byproducts of cellular metabolism and normal physiologic processes. Some studies have shown that normal levels of ROS for sperm maturation, chemotaxis, acrosome reaction, zona pellucida binding, hyperactivation, capacitation, and sperm-oocyte fusion are needed. Additionally, ROS are crucial intermediaries that have some roles in gene regulation and vascular tone within the testis(12).