Abstract

Cultured mouse early embryos often fail to develop to the blastocyst stage, although 2-cell block can be released by culturing in CZB medium. We hypothesized that fructose in culture medium may improve the in vitrodevelopment of mouse embryos. To evaluate the embryotrophic role of fructose, mouse embryos were cultured in CZB medium contain fructose (0.5, 1.0, 2.5 or 5.0mM). In this study, we compare whether glucose or fructose is metabolized most easily by mouse embryos at different stages of development. Seven-8- week-old cell block strain ICR mice were naturally mated after super ovulation. One-cell embryos were cultured in CZB medium supplemented with fructose.

When EDTA was added, 1-cell embryos developed to blastocysts but they did not develop in the presence of only fructose. The number of blastocysts and hatched blastocysts was significantly increased by the addition of fructose compared with that without fructose. The uptake and oxidation of 14C-fructose by pre-implantation embryos were significantly higher than those of 14C-glucose at all stage of embryo development. Furthermore, the quality of embryos produced by fructose and di-peptides, AlaGln or GlyGln supplementation instead of glutamine established this as an effective culture system for mouse embryos. The addition of AlaGln or GlyGln significantly increased the number of blastocysts and hatched blastocysts.

We improved the CZB medium with fructose, and determined that supplementation with AlaGln or GlyGln may be beneficial for culture medium for mouse early embryos.

Keywords: Embryo culture; Fructose; Glucose; Mouse embryo; Oxidation

Abbreviations: TCA: Tricarboxylic Acid Cycle; GlyGln: L-glycyl-L-Glutamine; PI: Propidium Iodide; PBS: Phosphate Buffered Saline; ICM: Inner Cell Mass; TE: Trophectoderm; PCA: Perchloric Acid; GFAT: Glutamine:Fructose-6-Phosphate Amidotransferase