The effects of melatonin on the development of mouse embryos in vitro. (A) In vitro cultured mouse embryos were observed by inverted fluorescence microscopy until ED 4.5 (EVOS® FL, AMG) (Scale bar = 200 µm). (B) A graph of each development stage. The numbers of embryos tested in each group are at least 20 and experiments were performed repeatedly at least three times. Data are expressed as mean ± standard error mean (SEM) expressed in one-way ANOVA. A significant difference between treatments indicates as *(p < 0.05) and **(p < 0.01). (C) In vitro developmental rates of mouse embryos cultured with LPS.