Evaluación de dos crioprotectores en la congelación de embriones bovinos producidos in vitro, en medios sintéticos

Abstract

The objective of this investigation was to determine the best cryoprotectant; To be used in a chemically defined medium, without biological compounds, using synthetic substitutes, capable of maintaining and / or improving the results of embryonic quality and survival after embryo preservation produced in vitro. A total of 176 PIVE embryos were obtained from oocytes from slaughterhouse ovaries. They were grouped into 2 groups (n = 85 and n = 91), 7 and 8 days respectively, and were subjected to slow freezing using 6 different media containing two cryoprotectants: 1.5M glycerol (GLY) and 1.5M ethylene glycol (ETY ) Combined with three compounds: 0.4% polyvinylpyrrolidone (PVP), 0.5 mg/ml hyaluronic acid (HA) and 0.4% bovine serum albumin (BSA). They were thawed and cultured and evaluated at 24, 48 and 72 hours for the variables membrane integrity, re-expansion and embryo hatching. Plasma membrane integrity was similar between cryoprotectants supplemented with synthetic proteins; however, addition of BSA increased the number of intact plasma membrane 7-day embryos in both cryoprotectants, but this difference was only significant with the combination of ethylene glycol plus hyaluronic acid. The combination of ethylene glycol with hyaluronic acid or with bovine serum albumin had lower and higher percentages of embryo expansion respectively, and only among these treatments the difference was significant. Therefore, the use of synthetic proteins in cryoprotectants may be an effective alternative to keep chemically defined freezing media and avoid sanitary risks