Efeito do estradiol e da progesterona no desenvolvimento e na qualidade de embriões bovinos produzidos in vitro

Abstract

The development and quality of bovine embryos co-cultivated with bovine oviduct epithelial cells (BOEC) supplemented or not with estradiol and progesterone were evaluated. Oocytes were matured and fertilized in vitro (MIV/FIV) (5%CO2/38.5oC). The BOEC were cultivated in TCM-199 with or without estradiol (E2) (24h), in the same conditions of MIV/FIV. Presumptive zygotes were transferred to BOEC in suspension after in vitro maturation and fertilization of bovine oocytes with thawed percoll-selected sperm. The zygotes were cultivated in CR2 medium containing or not progesterone (P4) (G1=P4+E2), (G2=E2), (G3=P4), and (G4=control). No significant differences (P>0.05) were found in the cleavage rates among G1, G2, and G4 (53.5%, 56.3%, and 51.7%) as well as in relation to the blastocystis (BL) rates (29.3%, 31.2%, and 28.7%). However, significant differences (P<0.05) were observed in the G3 for both variables (34.5% and 16.4%). G1 and G2 showed hatching rates higher (P<0.05) than the other groups (23.3%; 23.2%), being G4 (19.3%) different from G3 (16.1%) (P<0.01). In the groups G1, G2, and G3, the total cell number of the BL increased (125.9, 128.4, and 123.6) (P<0.05) compared to G4 (112.5). These results demonstrate that the treatment of the BOEC with estradiol in first the 24 hours of culture can be used separately or in combination with the progesterone to improve the quality of bovine embryos produced in vitro.