RESUMO
In vitro maturation (IVM) is one of the most important steps in in vitro embryo production (IVEP). It is a complicated procedure in which nuclear and cytoplasmatic changes in oocytes appear. In order to carry out the in vitro maturation procedure correctly, it is necessary to provide the oocytes with as close to a natural (in vivo) environment as possible. Many factors contribute to the overall poor quality of in vitro-matured oocytes. One important factor may be oxidative stress (OS). The generation of oxidants, such as reactive oxygen species, is common under culture conditions. The solution for OC treatment and prevention is antioxidants. In the last 5 years, many studies have examined different antioxidants and their effects on in vitro maturation of oocytes and embryo production. The aim of this systematic review was to present the achievements of scientific research in the last five years, in which the effects of many antioxidants were tested on bovine oocyte maturation and embryo production.
RESUMO
PURPOSE: this study was conducted on the effects of vitrification cryotop method on gene expression of mature oocytes in Mus musculus. METHODS: transcript analyses of three mouse genes, namely Mater, Hook1 and Sod1, were performed upon non-vitrified and vitrified oocytes with different concentrations of dimethyl sulfoxide (DMSO) and ethylene glycol (EG),15%: 7.5% DMSO + 7.5% EG, and 30%: 15% DMSO + 15% EG, using cryotop following normalization of transcripts with Hprt1 by nested quantitative PCR. RESULTS: vitrification caused down-regulation of Mater and Hook1 and up-regulation of Sod1 when lower concentrations of cryoprotectants were used as opposed to the control group. The relative expression of Sod1 in vit(2) (30% v/v) was significantly higher than vit(1) (15% v/v)(.) Quantitative transcript analysis of Mater and Hook1 for the vit(2) condition failed to produce any data. Survival rates were the same for both vitrification treatments and significantly lower than control group. CONCLUSIONS: although vit(1) treatment had lower survival rate compared to control group, it demonstrated better stability comparing to vit(2) based on the transcript analysis.
