Effect of inositol and glycine with increasing sodium chloride and constant osmolality on development of rabbit embryos

Abstract

Many commercially available culture media have a high sodium content as sodium chloride and sodium bicarbonate. We examined the effects of osmolytes, inositol and glycine, on embryos cultured in synthetic RD medium with a lower concentration of NaCl (93 mM) and a higher concentration of NaCl (116 mM) with media held constant at 270 mosmols. There were no significant effects of either glycine or inositol on embryo growth when the embryos were cultured in RD medium with 93 mM NaCl (P > 0.05). Culture of one-cell embryos for 72 h in RD medium with 93 mM NaCl, 116 mM NaCl and 116 mM NaCl containing 0.56 mM inositol resulted in 77%, 14% and 55% expanded blastocysts, respectively (P < 0.05). Corresponding values for two-cell embryos cultured for 67 h were 84%, 34% and 66% expanded blastocysts (P < 0.05). When one-cell and two-cell embryos were cultured in RD medium with 93 mM NaCl, 116 mM NaCl, 116 mM NaCl plus 1 mM glycine and 116 mM NaCl plus 1 mM glycine and 0.56 mM inositol, expanded blastocysts from one-cell embryos were 79%, 19%, 49%, and 48%, respectively (P < 0.05), and expanded blastocysts from two-cell embryos were 91%, 32%, 52%, and 53%, respectively (P < 0.05). Inositol and glycine presumably behave as osmolytes in providing substantial protection for rabbit one-cell and two-cell embryos cultured in a medium with high NaCl concentration.