RESUMEN
The follicle is a dynamic microenvironment in the ovary where the oocyte develops. Intercellular communication between somatic cells and the oocyte inside the follicle is essential to generate a competent gamete. Extracellular vesicles are nanoparticles secreted by cells that mediate cell-to-cell communication in the follicle microenvironment and can be obtained from the follicular fluid. These extracellular vesicles have been studied as biomarkers and supplementation tools to mimic physiological conditions during assisted reproductive techniques because they are vehicles of bioactive molecules. Therefore, this paper reviews the importance of changes in the ovarian follicle and the effects of extracellular vesicles from follicular fluid during oocyte maturation and early embryo development. Finally, we propose that is important to consider the source of the extracellular vesicles to improve diagnostic methods and to increase invitro embryo production.
Asunto(s)
Desarrollo Embrionario/fisiología , Vesículas Extracelulares/fisiología , Oocitos/fisiología , Oogénesis/fisiología , Animales , Células Cultivadas , Técnicas de Cultivo de Embriones/métodos , Técnicas de Cultivo de Embriones/veterinaria , Embrión de Mamíferos/citología , Exosomas/fisiología , Femenino , Técnicas de Maduración In Vitro de los Oocitos/métodos , Técnicas de Maduración In Vitro de los Oocitos/veterinaria , Folículo Ovárico/fisiologíaRESUMEN
The objective was to evaluate the effect of mastitis by somatic cell count (SCC) on follicular growth, ovulation, oocytes and cumulus cells quality and on the concentration and size of exosomes in follicular fluid of dairy cows. In the study, crossbred cows (Bos taurus - Holstein x Bos indicus - Gir) were classified for analysis as Control (SCC<200.000â¯cells/mL) and Mastitis (SCC>400.000â¯cells/mL) groups. In experiment 1 (follicular dynamics), cows (nâ¯=â¯57) were submitted to ultrasound evaluations every 24â¯h, from progesterone-releasing-intravaginal-device (PRID) removal (D8) until 48â¯h later (D10). Thereafter, evaluations were performed every 12â¯h, until ovulation or up to 96â¯h after PRID removal. In experiment 2 (oocyte, cumulus complexes, and follicular fluid evaluation), cows (nâ¯=â¯26) were submitted to follicular aspiration (OPU) for oocyte quality and cumulus cells transcript evaluation. The amount of cumulus complexes transcripts (BCL2, BAX, PI3K, PTEN, FOXO3) was determined by Real-Time Polymerase Chain Reaction. Moreover, seven days after the OPU session, the dominant follicle was aspirated. Exosomes were isolated from the follicular fluid for evaluation of particle size and concentration. Ovulation rate [Control 77.4% (24/31) and Mastitis 57.7% (15/26); Pâ¯=â¯0.09] and viable oocytes rate [Control 59.1% (130/220) and Mastitis 41.9% (125/298); Pâ¯=â¯0.01] were higher in Control animals. Additionally, there was a greater number of degenerate oocytes [Control 6.7⯱â¯1.2 and Mastitis 13.3⯱â¯5.5; (Pâ¯=â¯0.001)] in subclinical mastitis cows. There was greater abundance (Pâ¯=â¯0.003) of BAX cumulus cell transcripts and exosome mean (Pâ¯=â¯0.03) and mode (Pâ¯=â¯0.02) was smaller in subclinical mastitis cows. In conclusion, ovulation rate, oocyte quality, and exosome diameter were smaller in cows with SCC>400.000â¯cells/mL.