Increased messenger ribonucleic acid expression of the cyclin-dependent kinase inhibitor p27Kip1 in cleavage-stage human embryos exhibiting developmental arrest

ObjectiveTo quantify p27 messenger RNA (mRNA) levels in human arrested and normally developing embryos and nonfertilized oocytes to determine whether the p27 protein abundance, reported in cleavage-stage embryos exhibiting developmental arrest, is regulated at the mRNA expression level.DesignReal-time reverse transcription quantitative polymerase chain reaction was used to quantify the expression of p27 in three samples: arrested embryos (group A, n = 29), normally developing embryos (group D, n = 34), and nonfertilized oocytes (group O, n = 20).SettingResearch laboratory working closely with a clinical IVF practice.Patient(s)Oocytes and embryos were obtained from patients undergoing assisted fertilization.Intervention(s)None.Main Outcome Measure(s)Quantification of mRNA transcripts.Result(s)The amount of p27 mRNA was statistically significantly higher in group A (mean ± SEM, 86,143 ± 42,496 relative units [RU]) compared with groups D (10,680 ± 3,850 RU) and O (3,555 ± 1,458 RU). Furthermore, in a group of 13 two- to four-cell arrested embryos, high levels of p27 mRNA (51,481 ± 31,120 RU) were found in comparison with the nonfertilized oocyte group (3,555 ± 1,458 RU).Conclusion(s)Cleavage-stage human embryos exhibiting developmental arrest show increased p27 mRNA expression. This probably is due to increased transcriptional activity.