DETECTION OF REACTIVE OXYGEN SPECIES (ROS) AND APOPTOSIS IN HUMAN FRAGMENTED EMBRYOS

In human in-vitro fertilization (IVF)-embryo transfer, the in-vitro cu lture environment differs from in-vivo conditions.at the oxygen concen tration is higher, and in such conditions the mouse embryos show a hig her concentration of reactive oxygen species (ROS) in simple culture m edia. ROS are believed to cause damage to cell membranes and DNA fragm entation in somatic cells. This study was conducted to ascertain the l evel of H2O2 concentration within embryos and the morphological featur es of cell damaged induced by H2O2. A total of 62 human oocytes and em bryos (31 fragmented, 15 non-fragmented embryos, 16 unfertilized oocyt es) was obtained from the IVF-embryo transfer programme, The relative intensity of H2O2 concentrations within embryos was measured using 2', 7'-dichlorodihydrofluorescein diacetate by Quanti cell 500 fluorescenc e imaging and DNA fragmentation was observed with transmission electro n microscopy and an in-situ apoptosis detection kit. The H2O2 concentr ations were significantly higher in fragmented embryos (72.21 +/- 9.62 , mean +/- SEM) compared to non-fragmented embryos (31.30 +/- 3.50, P < 0.05) and unfertilized oocytes (30.75 +/- 2.67, P < 0.05), Apoptosis was observed only in fragmented embryos, and was absent in non-fragme nted embryos. microscopic findings confirmed apoptotic bodies and cyto plasmic condensation in the fragmented blastomeres. We conclude that t here is a direct relationship between increased H2O2 concentration and apoptosis, and that further studies should be undertaken to confirm t hese findings.