The Proteomics of Human Follicular Fluid on the Day of Oocyte Retrieval in in Vitro Fertilization Cycle

To investigate the main proteins in HFF on the day of oocyte retrieval in controlled ovarian hyperstimulation (COH) cycle. The proteins of HFF from 17 patients in COH cycles were tested. The protein’s molecular functions, biological process and pathways were analyzed. Seventeen patients aged between 23 and 35 years with fallopian tube occlusion were included in the study. All of them received long pituitary down regulation and COH protocol. When more than three follicles reached 18 mm in diameter, 10000 IU of hCG was administered and oocyte pick-up was performed 36 h later under the guidance of transvaginal ultrasound. At oocyte retrieval, the biggest pre-ovulatory follicle was first aspirated, the HFF collected by centrifugation and stored at -80.C for later testing. The HFF were pooled and tested by Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and mass spectrum analysis for proteomics. The results of mass spectrometrum testing were retrieved in data base Swissprot . The protein’s molecular functions and the biological processes were analyzed by software QuickGo. The proteins’ pathways were analyzed by website Kyoto Encyclopedia of Genes and Genomes. Altogether, 206 proteins were identified. The main functions of the identified proteins are binding (69%)and enzyme related activity (15%); the dominant biological process is response to stress (16%) and metabolic process (14%). The pathway analysis showed that complement and coagulation cascades rank second just next to metabolic pathways. As the ovarian follicle is a relatively isolated structure with blood barrier, so quite a part of nutrients, metabolites and regulating factors were stored by binding, and the reactive oxygen species (ROS) which is the main target in response to stress were counteracted by antioxidants contained in follicle. This might explains the main follicular function and main biological process in HFF. Ovulation is a acute phase response in which complement activation, immune response and blood coagulation are involved in. This might explains why complement and coagulation cascades is the important pathways in HFF on the day of oocyte retrieval. In summary, this study will help us to understand the mechanism of follicular development, at least in the COH cycle.