1. Although in vitro maturation (IVM) of oocytes is an important part of assisted reproduction, the developmental rate of embryos from IVM oocytes is lower than in vivo counterparts. It has been shown that follicle-stimulating hormone (FSH) increase cAMP accumulation oocytes during follicle growth and that an artificial increase of intracellular cAMP before culture significantly improves oocyte developmental competence in cattle and mice. Here, we show that forskolin and 3-isobutyl-1-methylxanthine treatment of prophase-I stage oocytes induced the expression of genes required for glycolysis, fatty acid degradation, and the mitochondrial electron transport system and improved mitochondrial functions and ATP levels in oocytes without involving nuclear maturation. We propose the existence of a comprehensive energy-supply system in oocytes under follicle-stimulating hormone stimulation as a potential explanation of how oocytes acquire developmental competence.

2. The fertility of women decreases with age because of factors such as an increased incidence of aneuploidies and—possibly—decreased mitochondrial activity in oocytes. However, the relationship between maternal age and mitochondrial function of their embryos remains unknown. We assessed the relationship in oocytes and embryos and the effect of L-carnitine on mitochondrial function. Although there were no direct relationships between maternal age and copy numbers of mitochondrial DNA at any embryo stages, the oxygen consumption rates (OCRs) of morulae decreased with maternal age. In a retrospective analysis, we noticed a decrease in the development rate of morulae to blastocysts along with maternal age. It was revealed that addition of L-carnitine to the culture medium significantly increased the OCRs of morulae and improved the morphologically good blastocyst formation rate per zygote compared to the sibling control embryos. Twenty-nine healthy babies were born from embryos cultured in L-carnitine-supplemented medium after single embryo transfers. Thus, this study shows that there is a decrease in the mitochondrial function in morulae with maternal aging and we suggest that L-carnitine is a promising culture medium supplement that might be able to counteract this factor.

3. During pregnancy, logically the fetus should have been attacked by the maternal immune system as it has paternal gene. However, it is not the case. In general, the fetus grows in the placenta without being rejected by the mother’s immune system. This is probably due of adequate suppression of the immune reaction. Previous study in mice revealed that activation of the alternative pathway of complement, one of the immune system pathways, induces pregnancy loss. In this study, we investigate whether an inhibitor of alternative pathway could prevent spontaneous pregnancy loss. CBA/J female mice mated with DBA/2 male mice show about 20% abortion rates and are used as the model for spontaneous pregnancy loss. These pregnant mice have both normal fetuses and lethal fetuses. We compare the distribution of complement protein expressions in the placentae of normal fetuses versus that of lethal fetuses, and clarify the relationship between the placental environment leading to abortions and inactivation of the complement.