Relação entre dosagem de glicose e proteínas totais no plasma seminal e a sobrevivência dos espermatozóides ao congelamento e descongelamento

Abstract

The process of freezing / thawing causes serious structural and functional modifications in samples of spermatozoa (SPZ). The presence of glucose and proteins in the seminal plasma is important for correction of these damages. Several tests have been proposed to predict the post-thaw recovery of SPZ, however the current methods are expensive and time-consuming. The aim of this study was to assess the value of semen glucose and protein measurements through dipstick before freezing to predict post-thaw recovery of SPZ. The seminal samples were analysed according the World Health Organization (WHO) guideline and cryopreserved in Tyb-G = Test Yolk Buffer with Gentamicine and 12 % glycerol / N2=nitrogene liquid for an average of 120 days. After thawing (37°C / 10 minutes), the vitality and mobility of the SPZ were analysed. In the samples with higher protein concentration ( 20g/dL, +++) the median recovery rate of live sperm was 74% (interquartile range 55-98%), whereas in the samples with lower protein concentration ( 1g / dL - / +) it was only 42% (26-73%, p <0.05). Conversely, seminal glucose concentrations were not associated with sperm recovery rates. In conclusion, seminal levels of glucose did not predict sperm recovery. However, the higher the levels of seminal proteins in the fresh sperm sample, the higher the rate of live sperm recovery after cryopreservation.