Estudo comparativo de três diferentes corantes para avaliação da integridade física da membrana plasmática de espermatozoides bovinos criopreservado

The morpho-functional nature of the plasma membrane assists to transport nutrients into the interior of spermatozoa, which requires the physical integrity of the membrane. This present study aims to compare three different dyes used to determine the integrity of the plasma membrane of bovine spermatozoa after freezing. The dyes tested were eosin 3% (p/v), trypan blue 0.4% (p/v), and propidium iodide (1.5 mM). Two sample groups were formed for the research. In the first group, one ejaculate was collected from each 11 animals, and in the second group, ten ejaculates were obtained from one animal. The fresh semen was evaluated using microscopy. The post-freezing samples were assessed using microscopy and flow cytometry. The results are presented in the form of average viability percentages ± standard deviations. The values membrane integrity, for the dyes eosin, trypan blue, and propidium iodide were 56.8±8.3%; 56.1±7.9%; 54.6±9.1%; respectively. There were no significant differences between the groups (p≥0.001). In comparative analysis of the techniques, flow cytometry enabled a greater number of cell evaluations, compared to phase contrast microscopy, with less variability and faster sample evaluation, hence adding value to the microscopy tests.