Effect of antioxidants added to the extender used for cryopreservation stallion semen

• Grant number: 11/09649-4
• Support Opportunities: Regular Research Grants
• Duration: November 01, 2011 - October 31, 2013
• Field of knowledge: Agronomical Sciences - Veterinary Medicine - Animal Reproduction
• Principal Investigator: Frederico Ozanam Papa
• Grantee: Frederico Ozanam Papa
• Host Institution: Faculdade de Medicina Veterinária e Zootecnia (FMVZ). Universidade Estadual Paulista (UNESP). Campus de Botucatu. Botucatu , SP, Brazil
• Associated researchers: Gabriel Augusto Monteiro

Abstract

The cryopreservation of equine spermatozoa is getting more and more space in the market because it prolongs the time of storage, giving advantages that goes since a better use of the genetic until to the marketing and use of semen. By keeping the sperm at low temperatures, the catabolism of spermatozoa is reduced, avoiding further damages to sperm. However, the full diffusion of this biotech is limited by oxidative stress. This process refers to the imbalance between antioxidant molecules and pro-oxidative molecules produced, also called reactive oxygen species (ROS). Among the damages that this imbalance can cause to sperm cells, we can detach the membrane lipid peroxidation, impairment of DNA integrity and apoptosis. The consequences of these injuries will be reflected in the morphology and function of sperm, prejudicing their fertilizing ability. The semen cryopreservation increases ROS production and decreases their antioxidant defense. The cells have an enzymatic and non-enzymatic antioxidant defense system. In the first one, several enzymes are involved in this mechanism, such as: the superoxide dismutase (SOD) that removes superoxide, converting it into hydrogen peroxide, catalase (CAT) that destroys hydrogen peroxide, converting it into water and oxygen, glutathione peroxidase (GPx) which is the most important in removing peroxide from the cells. In the non-enzymatic system, low molecular weight are part of compounds, including vitamins C and E, and melatonin which was recently confirmed as an antioxidant in many tissues, detected its presence in seminal plasma and its receptors in the membrane of the spermatozoa.Considering that the seminal plasma is a natural source of antioxidant protection to sperm, and in the process of cryopreservation it's removed, it's believed that several damages could be minimized if the process maintains a certain amount of plasma. (AU)