Effects of Glucose on Blastocyst Formation and Their Cell Numbers of Mouse Embryos

Park, Sung Baek; Kim, Ji Chul; Park, Kee Sang; Lee, Taek Hoo; Chun, Sang Sik; Song, Hai Bum

Abstract

OBJECTIVE
Mammalian embryos undergo changes of energy environment for transfer from oviduct to uterus. An experimental design was used to examine the effects of glucose on the development in vitro of mouse embryos.
METHODS
Two cell embryos were recovered from ICR female mice (3-4 weeks) at 46-50 hrs after 5 IU hCG injection (mated just after hCG injection) and cultured in 50 micro gram MEM droplets supplemented with nothing (control; n=46), 0.5 mM glucose (Group A; n=46) or 3.15 mM glucose (Group B; n=46) under mineral oil. All experimental media were supplemented with 20% human follicular fluid. Results were observed: (i) the number of zona-intact blastocysts (ZiB); (ii) the number of zona-escaped blastocysts (ZeB; hatching~hatched); (iii) the mean cell numbers; and (iv) the proportion of inncer cell mass (% ICM) in the blastocysts.
RESULTS
Total blastocyst formation rates were (NS) in glucose groups (group A: 52.2; B: 47.8%) than control group (60.9%). ZiB rates the highest (p<0.05) in control (47.8%) than those in group A (21.7%) and B (28.3%). ZeB rates the highest (NS) in group A (30.4%) than those in control (13.0%) and group B (19.6%). Blastocysts, cultured in group B (50.5), had the highest (NS) mean cell numbers compared with the others (control: 39.2; group A: 45.6). The % ICM in blastocysts cultured in group A (20.6%) was the highest (NS) than those of other tested groups (control: 15.2%; group B: 13.9%).
CONCLUSION
This study shows that a low dose of glucose added to culture medium increases the developmental capacity of 2 cell embryos in mice.