GSE75559
Effects of High Hydrostatic Pressure on Expression Profiles of In Vitro Produced Vitrified Bovine Blastocysts
High hydrostatic pressure (HHP) has been used to pre-condition embryos before essential, yet potentially detrimental procedures such as cryopreservation. However, the mechanisms for HHP are poorly understood. We treated bovine blastocysts with three different HHP (40, 60 and 80 MPa) in combination with three recovery periods (0, 1h, 2h post HHP). Re-expansion rates were significantly higher at 40 and 60 but lower at 80 MPa after vitrification-warming in the treated groups than controls. Microarray analysis revealed 399 differentially expressed transcripts, representing 254 unique genes, among different groups. Gene ontology analysis indicated that HHP at 40 and 60 MPa promoted embryo competence through down-regulation of genes in cell death and apoptosis, and up-regulation of genes in RNA processing, cellular growth and proliferation. In contrast, 80 MPa up-regulated genes in apoptosis, and down-regulated protein folding and cell cycle-related genes. Moreover, gene expression was also influenced by the length of the recovery time after HHP. The significantly over-represented categories were apoptosis and cell death in the 1h group, and protein folding, response to unfolded protein and cell cycle in the 2h group compared to 0h. Taken together, HHP promotes competence of vitrified bovine blastocysts through modest transcriptional changes. Overall design: 4*3*2 design experiment. The following treatments were included: (1) Control embryos were left untreated in the incubator (one atmospheric pressure or 0.1 MPa); (2) treatment groups were assigned to 40, 60 and 80 MPa HHP for 1h at either 24°C (room temperature) or 39°C (body temperature), followed by three different recovery time periods (0, 1 and 2h) post-HHP in the holding medium. Biological replicates: 3 control replicates. Technical replicates: dye-swap.