Effects of prostaglandin E₂ and F_2α on peri-implantation development of mouse embryos in vitro

Abstract

The effects of exogenous prostaglandin (PG) E₂ and F_2α on the morphology and lactate dehydrogenase (LDH) activities of pre-implantation mouse embryos in vitro were studied. A 24-hour exposure from 0.01 to 10 μg/ml of PGE₂ at the 4-cell or morula stages had no effect on the morphology of embryos during the 144 hours in culture. Exposure to 10 μg/ml PGE₂ at the blastocyst stage accelerated and enhanced spreading of the trophoblast in vitro. Embryos treated at 0.01 to 10 μg/ml PGE₂ at various stages all showed a more rapid decline in LDH activity from morula to blastocysts. Treatment with 50 or 100 μg/ml PGE₂ led to abnormal morphology of embryos in vitro. In contrast, continuous treatment with 0.01 to 100 μg/ml PGF_2α from 4-cell to early post-implantation (day 8) had no effect on the morphology of embryos, although breakdon of LDH was again accelelrated. These results suggest that the peak of PGE₂ secretion on day 4 of pregnancy in mice may enhance trophoblastic outgrowth, and the lower levels of PGE₂ and PGF_2α secreted earlier in pregnancy modulate the development of pre-implantation mouse embryos.