Oestrogen and Progesterone Receptor Gene Expression in Canine Oocytes and Cumulus Cells Throughout the Oestrous Cycle

Abstract

The aim of this research was to analyze oestrogen receptor-alpha (ERalpha), ERbeta and progesterone receptor (PR) gene expression in the canine oocyte and cumulus cells throughout the oestrous cycle. Ovaries from 38 bitches were recovered after ovariohysterectomy and sliced. The phase of the oestrous cycle was determined by vaginal cytology, vaginoscopy and serum hormonal measurements. Oocytes were mechanically denuded by repeated pipetting. For each phase of the cycle, a sample was composed by a pool of 50 oocytes (sample number: prooestrus = 3, oestrus = 8, dioestrus = 5 and anoestrus = 5) or a pool of cumulus cells (prooestrus = 4, oestrus = 7, dioestrus = 4 and anoestrus = 6). Oocyte and cumulus cells' total RNA was isolated and reverse transcription was conducted to perform real-time PCR. Oestrogen receptor-alpha was expressed throughout the cycle in the oocyte (33.33%, 25.0%, 20.0% and 60.0% for prooestrus, oestrus, dioestrus and anoestrus, respectively) and cumulus cells (50.0%, 47.14%, 25.0% and 66.67% for prooestrus, oestrus, dioestrus and anoestrus, respectively). In the oocyte, the ERbeta was also expressed in all phases of the cycle (33.33%, 50.0%, 20.0% and 60.0% for prooestrus, oestrus, dioestrus and anoestrus, respectively), whereas in cumulus cells, ERbeta was only expressed during prooestrus (50%) and oestrus (14.29%). Interestingly, while the oocyte PR was not detected in any phase of the cycle, this receptor was expressed during prooestrus (50%), oestrus (42.86%) and anoestrus (16.67%) in cumulus cells. In conclusion, canine oocytes express ERalpha and ERbeta throughout the oestrous cycle, however, there is a lack of PR expression in all these phases. Moreover, in cumulus cells, only ERalpha was expressed throughout the oestrous cycle.

Composing the Early Embryonic Microenvironment: Physiology and Regulation of Oviductal Secretions

“…In cattle, HSP90B1, HSP27, and GRP78 (also called HSPA5), among other proteins, were identified as interacting with spermatozoa [46]. From in vitro studies, it is known that oviductin, osteopontin, and complement C3 interact with the early embryo and support its development [47,48]. Recently, using mass spectrometry, more than 50 OF proteins, including oviductin, several annexins, alpha-2-macroglobulin, and galectin-3, were shown to interact with the cattle embryo [49].…”

Expression Profiles of the Progesterone Receptor, Cyclooxygenase-2, Growth Differentiation Factor 9, and Bone Morphogenetic Protein 15 Transcripts in the Canine Oviducts during the Oestrous Cycle

“…These paracrine factors play a crucial role in oocyte development, but little is known about their expression and function in the oviduct. The canine oviducts undergo physiological and hormonal changes according to the ovarian cycle [32]. According to our previous studies, the mRNA levels of GDF-9 and BMP-15 in canine follicles and COCs are not expressed equally during the follicular development throughout the ovarian cycle, suggesting a specific regulation and temporal changes in their expression [33,34]; thus, the function and dynamics of gene expression of GDF-9 and BMP-15 in the oviducts may vary in the same way due to these changes.…”