P-686 Long photoperiod exposure results in glycometabolism disorder in the cumulus-oocyte complex in SD rats

Abstract

Abstract Study question Does long photoperiod exposure cause glycometabolism changes in the cumulus-oocyte complex? Summary answer The levels of key enzymes and substrates involved in glycometabolism have changed in the cumulus-oocyte complex in SD rats due to circadian rhythm changes. What is known already Circadian rhythm is essential for maintaining the required reproductive activities in mammalians. In our previous research, long photoperiod exposure results in the reduction of ovulation number and the increase of ROS level in oocytes. In the process of oocyte maturation, the tricarboxylic acid cycle and energy metabolism gradually increase, while the ability of the oocyte to absorb glucose is low. It is mainly metabolized by cumulus granulosa cells into pyruvate and then transported to oocytes for subsequent metabolism. Metabolomics is a comprehensive analysis of small molecules, which provides key information about cellular metabolic states. Study design, size, duration Female SD rats, 6-8 weeks old, were randomized into two groups. The rats (n = 20) were exposed to the control photoperiod (12 hours light/12 hours dark) or long photoperiod (16 hours light/8 hours dark) for 12 weeks. Participants/materials, setting, methods Cumulus-oocyte complexes were collected after ovarian stimulation and numbers were counted. The parameters compared include MII rate, fertilization rate, and ovarian follicle number. We used mass spectrometry-based metabolomics to directly measure metabolite abundance. The glycometabolism pathway and its regulatory signaling molecules were analyzed by qPCR and/or Western blots. Main results and the role of chance Long photoperiod exposure significantly reduced the ovulation rate, MII rate and fertilization rate. Interestingly, we find secondary follicle and antral follicle were decreased (p < 0.01), while primordial follicle and primary follicle were increased (p < 0.01). We identified a total of 318 metabolites in COC. Among them, 59 metabolite levels have significant differences between the two groups (FDR < 0.05). The metabolical function analysis suggested that the phosphatidylinositol phosphate metabolism, pyruvate metabolism, phosphatidylcholine biosynthesis, and glycolysis pathways were influenced by circadian interference. In addition, hexokinase, glucose-6-phosphate isomerase, phosphofructokinase glyceraldehyde 3-phosphate expression level were down regulated. Limitations, reasons for caution More studies are required to address how clock gene regulating glycometabolism process. And Translating results in rat model to the human setting is a limitation of this study. Wider implications of the findings Our study findings are first to demonstrate that glycolmetabolism is regulated by long photoperiod exposure in follicle development. This knowledge could help to develop strategies to modulate specific recovery strategies based on metabolic regulator to improve human IVF. Trial registration number Not applicable