The effect of melatonin on in vitro fertilization and embryo development in mice

To examine the effect of melatonin on in vitro fertilization and embryonic development, mouse embryos after insemination in vitro were cultured in a p hysiological medium with or without melatonin. Melatonin increased the fert ilization rate significantly at a concentration between 10(-6) and 10(-4) M (27.6 vs. 43.9 or 40.4%, P < 0.01). Furthermore, a significant increase in the rate of embryos reaching the four-cell stage (16.0 vs. 26.7%, P < 0.01 ), the eight-cell stage (12.1 vs. 25.8 or 23.5%, P < 0.01), and blastulatio n (8.9 vs. 23.5 or 17.5%, P < 0.01) was observed when the embryos were cult ured in a medium containing 10(-8) or 10(-6) M melatonin. These results dem onstrate that melatonin supports fertilization and early embryo development after in vitro fertilization.