Lipossomas e betacaroteno encapsulado na refrigeração do sêmen canino

Abstract

Currently, studies have highlighted manipulation of membrane stabilizing agents, such as soy phosphatidylcholine liposomes, considered the primary site of damage during cryopreservation, and implementing the use of antioxidants, such as carotenoids, in order to minimize oxidative sperm stress. The first experiment aimed to evaluate the biocompatibility of 4 liposomes containing 45% (S45), 75% (S75), more than 98% (S100) of soy phosphatidylcholine and β-carotene encapsulated in S45 (SCAR), in two base diluents TRIS-glucose and egg yolk plasma and possible concentrations of use. The sperm kinetics of canine semen refrigerated at 5°C by the automated system (CASA) was evaluated after the cooling curve at 3h, 24h, 48h, 72h and 96h of refrigeration. Egg yolk plasma was shown to be superior in maintaining motility parameters at 72h and greater biocompatibility with liposomes (p < 0.05). Liposomes S75 and SCAR at a concentration of 1.25mM were more efficient in maintaining progressive motility, distance parameters, velocity, straightness, linearity, oscillation coefficient, head and flagellar movement of refrigerated canine semen. In the second experiment S45, S75, S100 and SCAR were studied, as additives, in canine semen refrigeration at 5°C for up to 4 days, in concentrations of 5mM; 1.25mM and 0.5mM. with evaluations after 24h, 48h, 72h and 96h. Kinetics were evaluated using the automated system (CASA) and parameters of cell integrity and functionality using flow cytometry. The use of soy phosphatidylcholine liposomes and encapsulated β-carotene decreased the production of intracellular reactive oxygen species in refrigerated canine semen (p < 0.05). The concentration of 0.5mM of liposome S75 allowed the highest means of total and progressive motility of the media studied in this experiment (p < 0.05). Additionally, 0.5mM of SCAR obtained progressive motility, speed, straightness and linearity superior to the control medium (p < 0.05).