Glass wool filtration of bull cryopreserved semen: a rapid and effective method to obtain a high percentage of functional spermatozoa

ARZONDO, MM; CABALLERO, J; MARIN BRIGGILER, CI; CETICA, P; DALVIT, G; VAZQUEZ LEVIN, M

THERIOGENOLOGY

ELSEVIER SCIENCE INC

Lugar: Amsterdam; Año: 2012 vol. 78 p. 201 - 209

0093-691X

Frozen-thawed bull sperm are widely used in assisted reproductive technologies, but cryopreservation negatively affects semen quality. Several sperm selection techniques have been developed to separate motile sperm from non-motile cells. The aim of the present study was to evaluate the effectiveness of the glass wool column filtration to select functional sperm from frozen-thawed bull semen samples. Frozen semen from six Holstein bulls were thawed and filtered through a glass wool column followed by assessment of routine and functional sperm parameters. In a set of experiments, sperm aliquots were also processed by the swim up to compare both selection methods. Samples recovered in the glass wool filtrate showed high percentages of viable (94 ± 3%), progressively motile (89 ± 4%), acrosome-intact (98 ± 1%) and non-capacitated (80 ± 10%) sperm; these values were higher (P<0.05) than those obtained after performing the swim up procedure. Moreover, the glass wool filtration yielded 67 ± 19% of motile cells in comparison with 18 ± 8% obtained with the swim up (P<0.05), calculated as the concentration of progressively motile cells selected relative to their concentration in the sample prior to the selection procedure. Glass wool-filtered sperm were capable to undergo capacitation-related events, as judged by the increase in the percentage of cells classified as capacitated by CTC staining (B-pattern) after incubation with heparin (50 ± 5%) in comparison with control conditions with no heparin (17 ± 4%) or heparin + glucose (16 ± 2%) (P<0.05). Moreover, they underwent acrosomal exocytosis in response to pharmacological (calcium ionophore A23187 and lysophosphatidylcholine) and physiological (follicular fluid) stimuli, and were found to fertilize in vitro matured cumulus-oocyte complexes and denuded oocytes (two-cell embryos: 72 ± 4% and 52 ± 6%, respectively). Altogether, the results show that glass wool filtration is a low-cost, simple, and highly effective procedure to select functionally competent sperm to be used in reproductive technologies in the bull, and may be utilized for other domestic and farm animals, as well as for endangered species.