| Autor: |
Lunardi FO; 1 Laboratory of Manipulation of Oocytes and Ovarian Pre-Antral Follicles, Faculty of Veterinary, State University of Ceará , Fortaleza, Brazil ., de Aguiar FLN; 1 Laboratory of Manipulation of Oocytes and Ovarian Pre-Antral Follicles, Faculty of Veterinary, State University of Ceará , Fortaleza, Brazil ., Apolloni LB; 1 Laboratory of Manipulation of Oocytes and Ovarian Pre-Antral Follicles, Faculty of Veterinary, State University of Ceará , Fortaleza, Brazil ., Duarte ABG; 2 University of International Integration of the Afro-Brazilian Lusophony , Redenção, Brazil ., de Sá NAR; 1 Laboratory of Manipulation of Oocytes and Ovarian Pre-Antral Follicles, Faculty of Veterinary, State University of Ceará , Fortaleza, Brazil ., Leal ÉSS; 1 Laboratory of Manipulation of Oocytes and Ovarian Pre-Antral Follicles, Faculty of Veterinary, State University of Ceará , Fortaleza, Brazil ., Sales AD; 1 Laboratory of Manipulation of Oocytes and Ovarian Pre-Antral Follicles, Faculty of Veterinary, State University of Ceará , Fortaleza, Brazil ., Lobo CH; 1 Laboratory of Manipulation of Oocytes and Ovarian Pre-Antral Follicles, Faculty of Veterinary, State University of Ceará , Fortaleza, Brazil ., Campello CC; 1 Laboratory of Manipulation of Oocytes and Ovarian Pre-Antral Follicles, Faculty of Veterinary, State University of Ceará , Fortaleza, Brazil ., Smitz J; 3 Follicle Biology Laboratory, Center for Reproductive Medicine , UZ Brussel, Brussels, Belgium ., Apgar GA; 4 Department of Animal Science, Food and Nutrition, Southern Illinois University , Carbondale, Illinois., de Figueiredo JR; 1 Laboratory of Manipulation of Oocytes and Ovarian Pre-Antral Follicles, Faculty of Veterinary, State University of Ceará , Fortaleza, Brazil ., Rodrigues APR; 1 Laboratory of Manipulation of Oocytes and Ovarian Pre-Antral Follicles, Faculty of Veterinary, State University of Ceará , Fortaleza, Brazil . |
| Abstrakt: |
The vitrification of preantral follicles followed by in vitro growth (IVG) could be valuable to produce fertilizable oocytes. However, the meiotic resumption rates of oocytes cultured from vitrified secondary follicles (SF) have been reported as suboptimal. This study aimed to verify two base media (alpha modification of minimum essential medium, α-MEM, and tissue culture medium 199, TCM199) on vitrified SF regarding different requirements during IVG. Sheep ovarian fragments were divided in six groups: (1) Fresh groups (Control α-MEM and TCM199): SF without vitrification; (2) Follicle-Vitrified (Follicle-Vit α-MEM and TCM199): SF vitrified after isolation; and (3) Tissue-Vitrified (Tissue-Vit α-MEM and TCM199): SF vitrified enclosed in ovarian fragments and, subsequently, isolated. The isolated SF were submitted to IVG for 18 days. Thereafter, the recovered cumulus-oocyte complexes (COCs) underwent in vitro maturation (IVM) and evaluation of chromatin configuration. Follicular granulosa cells were analyzed for their gene expression of Bax, Bcl2, and Connexins (CX) 37 and 43. COCs from in vivo antral follicles were used as in vivo control. Data were analyzed by analysis of variance, Tukey, and chi-square tests. Differences were considered significant if p-value is <0.05. Follicle-Vit groups had higher (p < 0.05) percentage of antrum formation compared with Tissue-Vit groups. Vitrification did not affect (p > 0.05) oocyte diameter postmaturation. Oocytes from Follicle-Vit in α-MEM reached metaphase II stage after IVM. Gene expression for CX37, CX43, and Bax was lower in Tissue-Vit groups. For Bcl2, the gene expression was the opposite. In conclusion, during IVG for 18 days, maximal oocyte meiotic resumption was not negatively impacted by vitrification and was greatest for isolated SF using α-MEM as a medium. |
