Effect of glucose and reactive oxygen species on boar sperm induced-acrosome exocytosis

Ejaculated boar spermatozoa can be liquid preserved for several days and be easily activated to produce physiological changes. One of the major changes is acrosome exocytosis that is physiologically related to capacitation. Glycolysis and reactive oxygen species (ROS) were studied regarding several boar sperm functions, but data available about their effect on boar sperm acrosome exocytosis are scarce. The objective of this work was to evaluate the effect of glucose and ROS on boar sperm acrosome exocytosis. We evaluated acrosome exocytosis by progesterone induction of capacitated sperm and assess viability, kinematics parameters, ROS levels, ATP content and Protein Kinase A activity in media with or without glucose and hydrogen peroxide or potassium chromate, as source of ROS. Our results show that glucose has no effect on acrosome exocytosis and also, it is not necessary for boar sperm capacitation, although it has a positive effect in the presence of ROS. On the other hand, ROS effects are related to spontaneous acrosome reaction. We conclude that glycolysis may function as a metabolic pathway that provides sustain but is not directly involved in boar sperm acrosome exocytosis and capacitation. Also, ROS do not promote capacitation in boar sperm, but affect spontaneous acrosome exocytosis.