Status of Glutathione during Oxidant-Induced Oxidative Stress in the Preimplantation Mouse Embryo1

Abstract

Experiments were conducted to elucidate the status of glutathione present in the oxidized (GSSG), reduced (GSH), and protein-mixed disulfide (GSSprotein) forms in preimplantation mouse embryos during development and after treatment with tertiary-butyl hydroperoxide (tBH) to cause oxidative stress. Glutathione was measured at picomolar levels by fluorimetric HPLC after derivatization of extracted embryonic samples with dansyl chloride. GSH content decreased approximately 10-fold from that in the unfertilized oocyte to 0.12 pmol/blastocyst, representing an estimated change in concentration from 7 to 0.7 mM. GSH levels were lower in embryos cultured in vitro than in embryos that developed in vivo. Addition of GSH to the culture medium improved in vitro development of mouse embryos, but surprisingly the addition of glutathione monoethyl ester did not. Addition of low levels of the oxidant tBH (13.2 microM) to culture medium decreased the percentage of two-cell and blastocyst stage embryos that exhibited further development. After 15-min exposure to 13.2 microM tBH, GSH levels were markedly decreased in the two-cell stage embryo (75%), but only slightly decreased (25%) in the blastocyst. The loss of GSH was accounted for by increases in GSSG and GSSprotein, indicating that the embryo was undergoing oxidative stress. These data indicate that preimplantation embryos are very sensitive to conditions that can cause oxidative stress and show also that their glutathione status changes dramatically during development.

Improvement in bovine embryo production in vitro by glutathione-containing culture media

“…The period of in vitro development at which this block occurs in the mouse embryo (the mid-two-cell stage to the early fourcell stage) is associated with a rise in reactive oxygen species such as HzOz (Nasr-Esfahani et al, 1990;Noda et al, 1991). The ineffective action of SOD and the significantly improved development in the culture medium for bovine embryos supplemented with GSH (Table 2) are in agreement with findings for mouse embryos cultured under high oxygen concentration in serum-free medium (Legge and Sellens, 1991;Gardiner and Reed, 1994). GSH showed a beneficial effect on development, and the greatest influence was with addition on day 6 postinsemination in the present work.…”

Effect of all-trans retinol on in vitro development of preimplantation buffalo embryos

“…In addition, glutathione levels change dramatically during preimplantation development, and this may be related to a role for oxygen radicals or thiol status in differentiation. Culturing embryos in vitro decreased their glutathione content; this may be a partial cause of the retarded development observed in vitro (Gardiner and Reed, 1994). Retinoids may protect the oxidative damage by maintaining adequate endogenous levels of antioxidant compounds and enzymes.…”

Committing Embryonic Stem Cells to Early Endocrine Pancreas In Vitro

“…MTG and its related thiol compounds, including 2-mercaptoethnol, can decrease oxidative stress by increasing intracellular glutathione concentration [49]. Glutathione concentration fluctuates at specific stages during early embryo development [50]. However, the mechanism by which MTG exerts its function in our cultured cells is currently unknown.…”