Congelación Ultra Rápida de Espermatozoides Humanos: Efecto sobre la Función Espermática y Producción de Especies Reactiva de Oxígeno

Abstract

The number of patients who wish to maintain their fertility is ever increasing. This group of patients includes cancer patients, those with fertility problems or viral infectious diseases acquired through sexual contact and others submitting to voluntary surgical sterilization; all of the above requiring freezing methods to adequately preserve sperm function. In the field of cryobiology the use of ultra-rapid freezing techniques has successfully preserved oocytes, embryos and ovarian tissue. This method has recently been incorporated in preserving male gametes. This study evaluates the effect of ultra-rapid freezing (vitrification) on sperm function of 10 normozoospermic donors. The sperm were selected by swim-up technique and the solution divided into two fractions. One fraction is vitrified by dipping directly into liquid nitrogen and the second fraction is used as control. In both fractions, viability, motility, mitochondrial membrane potential (YMMit) DNA integrity, spontaneous and induced acrosome reaction and intracellular superoxide (O2.-) were determined. It was noted that vitrification preserves cell function in a great number of spermatozoon, and is also simple, rapid and cost effective as this method does not require freezing equipment. There is however, significant activation of the production of reactive oxygen species, which leads to premature sperm capacitation, an event necessary to modulate particularly when using these cells in intrauterine insemination techniques. Future studies with addition of antioxidants to freezing media are necessary to further improve this technique.