Metabolic requeriments associated with GSH syntesis during in vitro maturation of cattle oocyte

FURNUS CC, MATOS DG, PICCO S, PERAL GARCÍA P, INDA AM, MATTIOLI G, ERRECALDE AL.

ANIMAL REPRODUCTION SCIENCE

Elsevier

Año: 2008 vol. 109 p. 88 - 99

0378-4320

Abstract Glutathione (GSH) concentration increases in bovine oocytes during in vitro maturation (IVM). The constitutive amino acids involved in GSH synthesis are glycine (Gly), glutamate (Glu) and cysteine (Cys). The present study was conducted to investigate the effect of the availability of glucose, Cys, Gly and Glu on GSH synthesis during IVM. The effect of the amino acid serine (Ser) on intracellular reduced/oxidized glutathione (GSH/GSSG) content in both oocytes and cumulus cells was also studied. Cumulus–oocyte complexes (COC) of cattle obtained from ovaries collected from an abattoir were matured in synthetic oviduct fluid (SOF) medium containing 8 mg/ml bovine serum albumin-fatty acid-free (BSA-FAF), 10 g/ml LH, 1 g/ml porcine FSH (pFSH) and 1 g/ml 17 beta-estradiol (17-E2). GSH/GSSG content was measured using a double-beam spectrophotometer. The COC were cultured in SOF supplemented with 1.5 mM or 5.6 mM glucose (Exp. 1); with or without Cys + Glu + Gly (Exp. 2); with the omission of one constitutive GSH amino acid (Exp. 3); with 0.6 mM Cys or Cys + Ser (Exp. 4). The developmental capacity of oocytes matured in IVM medium supplemented with Cys and the cell number per blastocyst were determined (Exp. 5). The results reported here indicate (1) no differences in the intracellular GSH/GSSG content at any glucose concentrations. Also, cumulus cell number per COC did not differ either before or after IVM (Exp. 1). (2) Glutathione content in oocytes matured in SOF alone were significantly different from oocytes incubated with SOF supplemented with Cys + Glu + Gly (Exp. 2). (3) Addition of Cys to maturation medium, eitherin vitro maturation (IVM). The constitutive amino acids involved in GSH synthesis are glycine (Gly), glutamate (Glu) and cysteine (Cys). The present study was conducted to investigate the effect of the availability of glucose, Cys, Gly and Glu on GSH synthesis during IVM. The effect of the amino acid serine (Ser) on intracellular reduced/oxidized glutathione (GSH/GSSG) content in both oocytes and cumulus cells was also studied. Cumulus–oocyte complexes (COC) of cattle obtained from ovaries collected from an abattoir were matured in synthetic oviduct fluid (SOF) medium containing 8 mg/ml bovine serum albumin-fatty acid-free (BSA-FAF), 10 g/ml LH, 1 g/ml porcine FSH (pFSH) and 1 g/ml 17 beta-estradiol (17-E2). GSH/GSSG content was measured using a double-beam spectrophotometer. The COC were cultured in SOF supplemented with 1.5 mM or 5.6 mM glucose (Exp. 1); with or without Cys + Glu + Gly (Exp. 2); with the omission of one constitutive GSH amino acid (Exp. 3); with 0.6 mM Cys or Cys + Ser (Exp. 4). The developmental capacity of oocytes matured in IVM medium supplemented with Cys and the cell number per blastocyst were determined (Exp. 5). The results reported here indicate (1) no differences in the intracellular GSH/GSSG content at any glucose concentrations. Also, cumulus cell number per COC did not differ either before or after IVM (Exp. 1). (2) Glutathione content in oocytes matured in SOF alone were significantly different from oocytes incubated with SOF supplemented with Cys + Glu + Gly (Exp. 2). (3) Addition of Cys to maturation medium, either