[Effects of homocysteine on post-implantation rat embryo cultured in vitro]

In order to investigate the effect of homocysteine(HCY) on the development of rat embryos, the post-implantation whole embryo culture(WEC) technique was used. Neural plate stage(GD9.5) rat embryos were explanted in rat serum medium(immediately centrifugal serum, ICS) with D,L-HCY(0,0.15, 1.5,2.0,4.0,6.0,8.0,10.0 mmol/L), and cultured for 48 hours. The results showed that HCY did cause damage to embryonic development and the damages of HCY on embryos were characterized in a significant dose-response pattern. The minimum teratogenic dose of D,L-HCY was 0.15 mmol/L, the incidence of dysmorphogenic embryos was 8.33%. Significant inhibiting effects of HCY on yolk sac(including reduced yolk sac diameter, shriveled surface, small or defective yolk sac vessels) and embryonic growth and morpholological differentiation were apparent with increased HCY, while HCY were 4 mmol/L or more (P < 0.05). The abnormalities included neural tube defects, delayed cardiac tube formation, pericardial effusion, incomplete flexion, small or missing forelimb buds and irregular somites, etc. These findings suggested that HCY might exert a direct effect on embryos and a "double effect" both on yolk sac and embryos.