Adição de quercetina e progesterona ao sêmen equino

Abstract

The variations and difficulties on maintaining the equine sperm parameters after manipulation (cooling and cryopreservation) take the scientists in a journey researching for substances that are able to be added to the dilution semen medium in order to keep or improve sperm viability. That being said, the present study has tested, in two different experiments, the addition of quercetin and progesterone to the equine semen. In the quercetin experiment, 10 Crioulo horses with ages between 4 and 10 years old were used, semen collection were performed with artificial vagina and 3 ejaculates of each animal were obtained (totalizing 30 ejaculates). The samples were submitted to 5 different treatments (0; 0,25mM; 0,5mM; 0,75mM and 1mM) of quercetin added in the freezing medium before the cryopreservation process. The analyzes concerning kinect sperm parameters were assessed in a subjective manner by a trained person in phase-contrast microscope and the parameters related to sperm population viability were examined by flow cytometry. Statistical analysis made from data obtained did not showed significant difference between treatments and the control (P > 0,05). The progesterone addition experiment was performed in two phases; the first phase consisted in the realization of a sperm toxicity test to the different hormonal concentrations. Semen collection was also realized with artificial vagina in a total of 10 Crioulo horses in ages between 4 to 10 years; posteriorly semen samples were submitted to cooling process until reach 5°C and adding the treatments containing 7 different progesterone concentrations (0; 1; 2,5; 5; 10; 100 e 1000 ng/mL) in 3 different times of exposition (0,5h; 3h e 24h). The second phase consisted in the sperm cryopreservation from 15 Crioulo horses collected with artificial vagina and with ages between 4 to 10 years. The ejaculates undergone to 5 different concentrations of progesterone (0; 1; 5; 10 e 100 ng/mL) added to freezingmedium previously to the cryopreservation process. In both analysis concerning progesterone experiment, kinect parameters were obtained by the Computer Assistant Sperm Analysis (CASA), as well as the flow cytometer tests regarding viable sperm population were utilized. The statistical data showed that after the toxicity test, with cooled semen, a significant improvement (P < 0,05) with the concentrations of 5 and 1000 ng/mL for 3-hour of exposition in velocity and average distance sperm parameters (DAP, DCL, DSL, VAP VCL, VSL). There was a significant raising on acrosome reaction at the 24-hour exposition time with the 5 ng/mL concentration treatment and also a significant decrease (P < 0,05) of lipid peroxidation (LPO) in the concentrations of 10, 100 and 1000 ng/mL in the 24-hour time of exposition. Information collected from thawing samples demonstrated an impairment (P < 0,05) in the reactive oxygen species, however the other parametersassessed did not differ from the control. From these data obtained in both experiments it is possible for us to conclude that the addition of quercetin to the freezing medium before the cryopreservation it is not interesting, once it does not presents significant improvements in sperm quality. On the other hand, the addition of progesterone to the fresh cooled semen demonstrated beneficial actions for the immediate use of semen, such as hyperactivation, capacitation and anti-oxidant effects.