SIRT2 Is Critical for Sheep Oocyte Maturation through Regulating Function of Surrounding Granulosa Cells.

Oocyte in vitro maturation is crucial for in vitro embryo production technology, which provides oocytes resources for in vitro fertilization and somatic cell nuclear transfer. Previous studies proved that SIRT2, a member of the sirtuin family, plays a role in oocyte meiosis, but its role in sheep oocyte maturation and its regulating mechanism remains unknown. Firstly, we confirmed the role of Sirt2 in sheep oocytes maturation by supplementation of SIRT2 inhibitor and activator. To further explore the specific mechanism, we performed knockdown of Sirt2 in granulosa cells and then cocultured them with oocytes. Moreover, we determined the effects of Sirt2 on granulosa cell oxidative apoptosis, cell migration, and diffusion, and examined its effects on granulosa cell mitochondrial function, mitophagy, and steroid hormone levels. The results showed that supplementation of SIRT2 inhibitor decreased the oocytes maturation rate (69.28% ± 1.28 vs. 45.74% ± 4.74, p < 0.05), while resveratrol, a SIRT2 activator, increased its maturation rate (67.44% ± 1.68 vs. 78.52 ± 1.28, p < 0.05). Knockdown of Sirt2 in sheep granulosa cells also reduced the oocytes maturation rate (47.98% ± 1.43 vs. 33.60% ± 1.77, p < 0.05), and led to decreased cell migration and expansion ability, oxidative apoptosis, abnormal mitochondrial gene expression, decreased mitochondrial membrane potential and ATP level, and increased mitophagy level. Overexpression of Sirt2 improved mitochondrial membrane potential and ATP level and improved mitochondrial function. Furthermore, we found that Sirt2 knockdown in granulosa cells promotes the secretion of P4 through regulating p-ERK1/2. In conclusion the present study showed that SIRT2 is critical for sheep oocyte maturation through regulating the function of ovarian granulosa cells, especially affecting its mitochondrial function.

Embarazo mediante tratamiento de maduración in vitro de ovocitos en paciente amenorreica y con historia de anorexia nervosa

La maduración in vitro (MIV) de ovocitos, generalmente utilizada en pacientes con ovario poliquístico y con síndrome de ovario poliquístico, ha sido aplicada para el tratamiento de infertilidad de una mujer con amenorrea secundaria y con historia de anorexia nervosa. Tras reiterados intentos infructuosos de estimulación ovárica por técnicas convencionales de reproducción asistida, se inició el tratamiento de MIV de ovocitos estimulándose los ovarios con FSHr durante el segundo, tercero y cuarto días del ciclo, aspirando los folículos antrales en el octavo día. Se obtuvo cuatro complejos cúmulo-ovocito, los que fueron cultivados en medio de maduración por 36 horas en presencia de FSH y hCG. Los ovocitos maduros en metafase II fueron fecundados mediante inyección intracitoplasmática de espermatozoides (ICSI) y los embriones obtenidos fueron congelados por vitrificación al segundo día. Un mes después, se preparó el endometrio con valerato de estradiol. Los embriones descongelados fueron cultivados por 24 horas adicionales y se transfirió tres embriones. La paciente logró gestación única evolutiva con embrión activo.

Oocytes in vitro maturation (IVM) usually used in patients with polycystic ovaries and polycystic ovary syndrome has been applied for the treatment of infertility in a woman with secondary amenorrhea and history of anorexia nervosa. After repeated unsuccessful attempts of ovarian stimulation for conventional techniques of assisted reproduction, IVM treatment was begun by stimulating the ovaries with rFSH during the second, third and fourth day of the cycle and aspiring antral follicles on the eighth day. There were four cumulus-oocyte complexes that were cultivated in the maturation media for 36 hours in presence of FSH and hCG. Mature metaphase II oocytes were fertilized by intracytoplamatic sperm injection (ICSI) and embryos were frozen by vitrification on the second day. A month later, the endometrium was prepared with estradiol valerate. Thawed embryos were cultivated for 24 additional hours and three embryos were transferred. The patient achieved an evolutionary single gestation with active embryo.