The evaluation of the metabolism of normal and metabolically challenged preimplantation embryos

Objective: Morphological assessment remains the primary method of embryo evaluation in ART. However, as a biomarker, noninvasive methods because of the well-known adverse effect of the invasive methods for assessing embryo metabolism has been needed besides morphological assessment. In our study, we aimed to determine and to measure of normal and metabolically challenged mouse embryo metabolism using FLIM and confocal microscopy via autofluorescence NADH and FAD. Method: Under different nutrient, different oxygen and mitochondrial uncoupler conditions, the response of the embryo metabolism has been determined using NADH and FAD via FLIM and using FAD via confocal microscopy. On the other hand, the expression patterns of Glut1 has been determined by immunofluorescence to reveal which metabolic pathway has been used to produce energy by anoxic embryos. Results: Embryo metabolism profiles have been revealed from the response of embryo metabolism under different nutrient and oxygen conditions using NADH and FAD via FLIM. Also, it has been showed that embryo metabolism can be measured using FAD not only other mitochondrial markers but also more selectively via confocal microscopy. Moreover, cell division of the anoxic embryos suggest a question: how these oxygen addicted precompaction embryos to produce energy could make it happen? Based on that question, we investigated the expression pattern of Glut1 and it is showed that expression of the Glut1 is increased and it is localized in the cell membrane under anoxia. Conclusion: In our study, for the first time, the detail information has been revealed about precompation mouse embryos via evaluation of the metabolism of the normal and metabolically challenged embryos. The data from our study may contribute to create a new biomarker to select the best embryo and also contribute biological and technical information for the future studies. Key words: Embryo metabolism, mitochondria, NADH, FAD, microscopy.