Bioquímica do plasma seminal e efeito do edta adicionado ao meio de congelamento do sêmen de cão doméstico

• Autor(a) principal: Ferreira, Letícia Bergo Coelho
• Data de Publicação: 2013
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/5180
• topic: Cão - Reprodução; Sêmen - Análise; Bioquímica; Ácido etilenodiaminotetraacético; Dog - Playback; Semen - Analysis; Biochemistry; ethylenediaminetetraacetic acid; CNPQ::CIENCIAS AGRARIAS::MEDICINA VETERINARIA::REPRODUCAO ANIMAL

One of the main deleterious factors inherent to the process of canine semen freezing is the large amount of sperm membranes lesions observed in the thawing. The freezing induce some destabilization of cell membrane and changes in the conformation between membrane receptors and ionic channels, promoting the calcium influx and increasing the probability of a premature acrosome reaction (AR), that invalidate the fertilizantion of the oocyte. The calcium is the principal inducing agent of the AR in vitro, and there is not recent reports about the biochemical composition of the seminal plasm and about the calcium levels that prevent the premature AR in the frozen of the domestic dog semen too. This study aimed to evaluate the alkaline phosphatase and cationic composition in seminal plasma of the fractions of dog ejaculate; and also test the effects of calcium amount reducing in freezing medium using the EDTA as a chelating agent. The semen was collected from three half-breed dogs. The sperm-rich fraction (SRF) and the prostatic fraction (PF) were separately collected. Both samples were evaluated by spectrophotometry, measuring the concentrations of calcium, sodium, potassium, alkaline phosphatase (AP), and the freezing medium. The fresh semen was evaluated by classical tests (strength, progressive motility, morphology, and membrane integrity). The remainder was divided into three aliquots that were diluted in a freezing medium based on tris-citrate-egg yolk, glycerol and equex with different concentrations of EDTA. The first treatment did not contain EDTA, treatment 2 contained 0.1% EDTA and the third, 0.25%. The most abundant cation in seminal plasma of these dogs was sodium, followed by potassium and calcium, respectively, both in SRF and in PF, without significant difference between the concentrations of these ions in both fractions. The AP obtained in SRF was significantly higher (p <0.000001) than that obtained in PF. There was a high concentration of calcium in the freezing medium based, that was significantly reduced in the treatments with EDTA. Deleterious effects were observed in all analyzed parameters in thawed semen compared with fresh semen (progressive motility, morphology, and membrane integrity). With the use of fluorescent probes, we did not note significant difference in the percentage of the plasmatic membranes e acrosomal membranes injured among the treatments with different EDTA concentrations. The extracellular medium has high calcium concentration, and despite the EDTA had significantly reduced the extracellular calcium in those treatments that it was added, there was not acrosomal membrane injury reduction in these treatments. This may have been caused because the concentration of this cation still remained high in comparision with its concentration in the original seminal plasma. We note too that the EDTA did not presented deleterious effects on the spermatozoa inside the evaluated parameters.