Efeito do Resveratrol associado a sacarose na vitrificação de tecido ovariano bovino

Abstract

Among the biotechnologies of animal reproduction, gamete cryopreservation has become a well established biotechnology, although it still presents some obstacles when it comes to the cryopreservation of oocytes and ovarian tissue. Our objective was to evaluate the effect of the association of the antioxidant resveratrol with sucrose on the vitrification of ovarian tissue of pre-puberty heifers and adult cows on the morphology and viability of preantral follicles. Twenty ovaries obtained randomly from the slaughter line in a local refrigerator, 10 ovaries from pre-puber heifers and 10 ovaries from adult cows were used, these were fragmented and distributed to different treatments: control (Co), toxicity (T) and vitrification (V), the toxicity and vitrification treatments submitted to the following vitrification solutions: Vitrification base solution (SBV) with 0.25M sucrose (VS), SBV with 10 μM resveratrol (VR) and SBV with sucrose and resveratrol (VS + R) at the same concentrations, after thawing, the ovarian fragments were evaluated for morphology and follicular viability by light microcopy and transmission electron microscopy, respectively. The data of the evaluated variables were submitted to normality tests using the Shapiro-Wilk, the percentage of normal and degenerate follicles in the experimental groups were analyzed by the Chi-square test, since variables that did not pass the normality test submitted to the Kruskall-Wallis test, considering (P <0.05) for determining differences between treatments (InfoStat Statistical Software INFOSTAT, 2012). Of the total of 2,610 preantral follicles evaluated, the average percentage of normal and degenerate was 65.51% and 34.49% respectively. And in the different toxicity and vitrification treatments and in relation to the adult and pre-pubertal groups there was no difference (p> 0.05). Secondary follicles differed (p≤0.05) in the control group when compared to primordial and primary follicles, even though these were presented in a smaller proportion in the different vitrification treatments in both groups of bovine females. The vitrified ovarian tissue fragments showed similar results to the fresh control. It can be concluded that natural antioxidant resveratrol when combined with sucrose contributes to the morphological preservation of preantral follicles of pre-puberty heifers and adult cows when subjected to the process of vitrification and reheating.