Mitochondrial Dysfunction and Apoptosis in Cumulus Cells of Type I Diabetic Mice

Impaired oocyte quality has been demonstrated in diabetic mice; however, the potential pathways by which maternal diabetes exerts its effects on the oocyte are poorly understood. Cumulus cells are in direct contact with the oocyte via gap junctions and provide essential nutrients to support oocyte development. In this study, we investigated the effects of maternal diabetes on the mitochondrial status in cumulus cells. We found an increased frequency of fragmented mitochondria, a decreased transmembrane potential and an aggregated distribution of mitochondria in cumulus cells from diabetic mice. Furthermore, while mitochondrial biogenesis in cumulus cells was induced by maternal diabetes, their metabolic function was disrupted as evidenced by lower ATP and citrate levels. Moreover, we present evidence suggesting that the mitochondrial impairments induced by maternal diabetes, at least in part, lead to cumulus cell apoptosis through the release of cytochrome c. Together the deleterious effects on cumulus cells may disrupt trophic and signaling interactions with the oocyte, contributing to oocyte incompetence and thus poor pregnancy outcomes in diabetic females

Influência da adição de níquel na síntese do SrSnO3 Influence of nickel doping on the SrSnO3 synthesis

Pós cerâmicos microestruturados de Sr1-xNi xSnO3 (x de 0 a 0,20) foram sintetizados com sucesso pelo método dos precursores poliméricos. Os precursores foram caracterizados por análise térmica. Três etapas de decomposição foram observadas: a primeira relacionada com o processo de desidratação, a segunda e a terceira são processos de combustão da matéria orgânica. A caracterização estrutural foi feita por difração de raios X, espectrofotometria de absorção óptica no infravermelho e espectroscopia Raman após calcinação a 700 ºC, indicando a presença da fase SrSnO3 ortorrômbica. Quando níquel II foi adicionado na rede cristalina do estanato, foi observada uma transição de fase, conduzindo a uma nova estrutura pseudo-cúbica. Com base nos resultados de Raman e difração de raios X, foi analisada a ordem-desordem a curto e longo alcance. Os resultados experimentais mostram a formação de fases secundárias quando níquel II é adicionado na matriz, com calcinação a 700 ºC.<br>Sr1-xNi xSnO3 (x from 0 to 0.20) powders were synthesized by the polymeric precursor method. The powder precursors were characterized by thermal analysis. Three decomposition steps were observed: the first step related to the dehydration process, the second and third ones assigned to combustion processes. The structural characterization was done by X-ray diffraction (XRD), infrared absorption spectroscopy and Raman spectroscopy after calcination at 700 °C, indicating the presence of orthorhombic SrSnO3. When nickel is added to the structure, a phase transition is observed, leading to the presence of a pseudo-cubic phase. Based on Raman and XRD results, the order-disorder at short and long range were analyzed. The experimental results show the formation of a secondary phase when nickel is added to the material and calcined at 700 ºC