Abstract: BACKGROUND ＆AIM: To evaluate the effects of hydroxyurea(HU) on embryonic development, effects of hydroxyurea on proliferation and differentiation were studied by using rat embryo midbrain(central nervous system, CNS) cell micromass culture. MATERIALS AND METHODS: Midbrain cells from 13-day rat embryos were harvested. After exposed to different doses of hydroxyurea in the culture medium for 5 days, proliferation and differentiation of neurons from midbrain cells were examined. RESULTS: Hydroxyurea could significantly inhibit the proliferation and differentiation of midbrain cells in a dose dependent manner, and could arrest neurogenesis and colony formation. The numbers of differentiated foci decreased with increasing concentration of HU, and nerve fiber bundle reduced during the differentiated foci,showing a typical dose-effect relationship. The IcV50 value of hydroxyurea was 0.078 mmol/L(5.9 μg/ml)and the IcD50 value was 0.018 mmol/L(1.37 μg/ml). The ratio of IcV50 and IcD50 was 4.33. CONCLUSION: Hydroxyurea is a non-specific inhibitor of cell proliferation and differentiation; it could potentially result in teratogenicity in vitro.

Key words: hydroxyurea, midbrain cell, cell differentiation, micromass culture, teratogenicity