The quality of oocytes is altered by endometriosis in a mouse model.

KLINSKY OG; WETTEN PA; CASAIS M; SAYEGH F; MICHAUT M

Congreso; Sociedad Chilena de Reproducción y Desarrollo (Octubre 2020); 2020

Endometriosis is a chronic disease characterized by the presence of endometrial tissue outside the uterine cavity. Approximately 10% of women in reproductive age are affected by endometriosis-associated infertility, and various causes, like anatomical alterations or implantation problems, have been evaluated. However, there is still no consensus on whether endometriosis disturbs oocyte quality and competence, or what is the molecular basis of its alterations. Therefore, the aim of the present work is to analyze the effects of endometriosis in the quality of mouse oocytes, analyzing the mitochondrial membrane potential (MMP) and ATP levels, the cortical actin state and the cortical granules exocytosis (CGE). CF-1 mice of 8- 12 weeks were used to develop endometriosis models through an autologous surgical induction. After 4 weeks of development, endometriotic and control females were hormonally stimulated to obtain mature oocytes (MII). Endometriosis generates a pro-inflammatory environment that possibly alters cellular energetic pathways. Consequently, MMP and ATP levels were evaluated in vivo. Although no differences were found with respect to MMP, ATP levels were significantly low in endometriotic oocytes. Then, the state of cortical actin was analyzed. Endometriotic oocytes presented a significantly higher relative fluorescence of the cortical actin. This led us to hypothesize that the CGE may be altered. For that reason, oocyted were stained and basal cortical granules density was calculated. There were no statistic differences between both groups. Consequently, we analyzed the CGE in parthenogenetically activated oocytes with strontium (Sr). While Sr-activated control oocytes exhibited a decrease in cortical granule density, Sr-activated endometriotic oocytes did not show the same pattern. Taken together, these preliminary results show that induced endometriosis would affect some molecular parameters in mouse oocytes, decreasing ATP levels of the cell, augmenting actin in the cortical zone and altering cortical granules exocytosis in activated oocytes.