The Effects of Retinoic Acid on Gastrulation of Hatched Mouse Embroyos

Kang, Byung Moon; Cheon, Yong Pil; Kim, Nak Yon; Kim, Chung Hoon; Chang, Yoon Seok; Mok, Jung Eun

Abstract

Retinoic acid(RA), formed in vivo by oxidation of retinol, is known as morphogenic signal. RA plays an active role in normal embryonic development at physiological concentration, but excess RA can be a powerful teratogen in human and animals. The present study was designed to examine the direct effect of RA on murine embryogenesis(gastrulation) and to define the specific development processes perturbed by RA. Five to fifteen blastocysts were randomly assigned to separate culture dishes of the experimental group. Various concentrations of RA(10(-9) M, 10(-7) M, and 10(-5) M) were used in culturing blastocysts. In the effect of RA on the normal grouwth of embryo, the rates of development to the stages of attachment, early egg cylinder(EEC), late egg cylinder(LEC), and early somite(ES)were significantly(p < 0.01) decreased as the RA concentration increased. Stil in the yolk sac formation rate, there was a significant, dose-dependent difference(p < 0.01) according to the RA concentration. In the degeneration of embryos by RA, the effect was more apparent as the concentration of Ra increased. The production rates of embryos devoid of egg cylinder region and embryos with abnormal egg cylinder region were increased (p < 0.01)in a dose-dependent manner according to RA concentration. In conclusion, RA probably act as teratogen at gastrula stage embryos in high concentration and effect of teratogenesis is dose-dependent.