Morphometric study of malformations induced by hypervitaminosis A on rat fetus Meckel cartilage, maxillary bone and mandible.

Morphological and histological studies were carried out to determine the effects on fetal development in rats of a single intraperitoneal injection of 150,000 I.U. of vitamin A, given to the mothers on the 10th day of gestation. The Meckel cartilage of malformed animals appeared to be diminished, with larger nuclei, less numerous isogenous nests, smaller cellular and thin perichondrium and more abundant cartilaginous matrix, which was less deeply stained by alcian blue. The maxillary bone and mandible of the treated fetuses showed thin and poorly calcified trabeculae, smaller medullary spaces and a less fibrous, and more cellular periosteum. These data were confirmed with morphometric techniques.