Nitric oxide as an early marker of human embryo metabolic cleavage in ART using fresh or thawed oocytes

Abstract

Objective To study a possible role of nitric oxide (NO) as a marker of development in the early phases of human embryo cleavage during assisted reproduction. Study design 179 women having ART were included. 123 women used fresh oocytes and 56 oocyte thawing cycles in the Center of Reproductive Medicine, Department of Obstetrics and Gynecology, Arcispedale S. Maria Nuova, between July 2005 and June 2006; 57 patients had IVF and 122 patients had ICSI. NO concentrations in IVF or ICSI embryo culture media were assessed by monitoring levels of NO stable oxidation products (nitrites/nitrates). Analysis of embryo quality was performed. Student’s t-test or Mann–Whitney and logistic regression model tests were applied to the data. Results In patients using fresh oocytes, there were greater NO production in embryos derived from ICSI than from IVF after 52 h of culture (38.64 μmol/L vs 11.2 μmol/L, p < 0.05). No correlation with embryo quality was observed. Embryos derived from fresh oocytes produce more NO than embryos from thawed oocytes both after 48 and 52 h of culture (16.12 μmol/L vs 6.83 μmol/L and 25.93 μmol/L vs 2.98 μmol/L respectively, p < 0.05). Conclusion(s) NO in embryo culture media is not a metabolic cleavage marker or a marker of embryo quality in ART. However, it could be an important parameter in the investigation of metabolism in frozen/thawed oocytes.