Chemical imaging and immunodetection of progesterone, prolactin and estrogen receptors in uterine tubes obtained from bitches under different reproductive conditions

Abstract

Maturation is the period in which the oocyte acquires the ability to be fertilized and so, in vitro maturation (IVM) depends mostly on the efficiency of the culture medium. However, IVM in dogs has been conveyed at low rates compared to other species, which limits the development of other biotechnologies of pivotal importance in the management of assisted reproduction such as fertilization, in vitro embryo production and cryopreservation (Farstad, 2000). Thus, it is essential the development of a culture medium specific for this species, which must provide an environment similar to the physiological and which preserves the viability of the oocyte and that allows the acquisition of meiotic competence. Considering that the maturation of canine oocytes occurs within the uterine tube and that they are exposed to different environments (follicular and uterine tube) during preparation for maturation, there is a clear demand of knowledge about the factors responsible for the acquisition of meiotic competence. For this reason, this project aims to study the microenvironment of uterine tube of bitches under different hormonal exposure and correlate them with findings on oocyte and intrafollicular content in order to recognize a chemical and biological pattern that may be involved in the regulation of maturation in this species. Therefore, the objectives of this project are: 1) Investigate the distribution of biomolecules in uterine tube samples harvest from bitches at the pre and post ovulatory period through the technique of chemical imaging by mass spectrometry (MALDI-IMS); 2) Verify the presence and localization of progesterone, estradiol and prolactin receptor in the uterine tube of bitches under different reproductive conditions; 3) Correlate the findings obtained through MALDI-IMS with those from immunohistochemistry in the pre and post ovulatory period. The experiments may contribute to the advance of knowledge about reproductive physiology in canid species and fill in gaps concerning the acquisition of meiotic competence, which may help in the development of a culture media most appropriate for the species. (AU)