Selection of a high quality subpopulation of frozen thawed bovine spermatozoa by filtration in a sephadex column. An assessment of functional effects of progesterone.

VINCENTI LM; FIOL DE CUNEO M; RUIZ RD; MARTINI AC; PONCE AA

Journal of experimental animal science

Urban and Fischer Verlag

Año: 2002 vol. 42 p. 93 - 101

  It is accepted  that cryopreservation exerts deleterious effects on functional characteristics of mammalian spermatozoa. Conventional procedures for processing frozen-thawed gametes, such as centrifugation, produce additional damage. In the present work, we investigated the efficacy of processing bovine cryopreserved semen by filtration in a Sephadex column (SF group) or by washing by centrifugation (100 g, 10 min, twice) (W group); the results obtained from both procedures were compared to untreated samples (C group). The effects of in vitro addition of progesterone (10 mM, 20 min) upon sperm functional activity were studied also. The evaluated sperm parameters were: concentration, motility (progressive or non progressive cells), viability and acrosome reaction. They were measured at time 0 (immediately after processing) or after 4 h incubation in capacitating conditions. Sperm concentration was (x10-6): 37.5± 5.4 in C, 8.3±2.1 in W and 12.5±2.9 in SF. The percentages of motile, progressive, viable or acrosome intact gametes were significantly higher in SF than in W or in C. In SF group, after 4 h incubation in capacitating conditions, progesterone  increased significantly the population of acrosome reacted cells whereas this parameter was not modified when the cells were incubated in absence of heparin. Motility and vitality were not modified by the hormone. We conclude that Sephadex filtration method is an adequate tool to obtain a subpopulation of spermatozoa with superior quality, as assessed by motility, viability and acrosomal integrity; besides, our results strongly support that, as in other species, progesterone would be a physiological inductor of acrosome reaction in bovines.