Studies on substantially increased proteins in follicular fluid of bovine ovarian follicular cysts using 2-D PAGE and MALDI-TOF MS

Proteins in normal and cystic FF samples were subjected to two-dimensional polyacrylamide gel electrophoresis (2-D PAGE) and were compared using silver stained gel images with PDQuest image analysis software. Peptides from these increased spots were analyzed by matrix assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS), and were identified based on the NCBI database by a peptide mass fingerprinting method.Comparative proteomic analysis showed 8 increased protein spots present in cystic FF. MS analysis and database searching revealed that the increased proteins in cystic FF were bovine mitochondrial f1-atpase (BMFA), erythroid associated factor (EAF), methionine synthase (MeS), VEGF-receptor, glyceraldehydes 3-phosphate dehydrogenase (GAPDH), heat shock protein 70 (HSP70), β-lactoglobulin (BLG) and succinate dehydrogenase Ip subunit (SD).Our results suggest that these proteins are overexpressed in BOFC, and that they may play important roles in the pathogenesis of BOFC. Furthermore, these proteins in the FF could be useful biomarkers for BOFC.BOFC is one of the most frequently diagnosed gynecological findings in cattle, and is a major reproductive problem in cows, causing infertility [1-3]. BOFC is generally defined as follicle-like structures of greater than 25 mm in diameter without a corpus luteum in both ovaries [1,4]. There have been several different hypotheses regarding the cause of BOFC, such as inherited factors, high lactation, aging, seasonal effects, nutritional condition, environmental estrogen and stress [1,2,4,5]. The primary cause of BOFC development has not been elucidated because of the variety of histological characteristics [1], various abnormal hormonal patterns [1,4], and differing therapeutic responses [1,4]. However, it is generally believed that cysts are formed in response to an "endocrine imbalance" [3,4,6]. Several hypotheses have been proposed suggesting that gonadotropin releasing hormone (GnRH) and gonad