Abstract
In order to ascertain the role of embryonic facial structure for the manifestation of genetic microphthalmia (mic), excessive vitamin A (VA) was administered to mic mice on day 8-9 of pregnancy, and the embryos and fetuses were examined. In non-treated mic embryos, the maxillary process grew upward and the optic vesicle was blocked from contact with the head ectoderm. In the VA-treated embryos, reduction of the maxillary process was marked and the lens was fairly well induced. The size of the lens and the eyeball of fetuses in the treated group was significantly larger than in the non-treated one. The incidence of histological abnormalities, such as incomplete detachment of the lens, incomplete closure of the embryonic fissure and persistent primary vitreous was reduced by the VA-treatment. These findings indicated that the morphological deviation of the embryonic facial structure played a significant role for the manifestation of the microphthalmia (mic).
