[Effect of maternal vitamin A deficiency on cranio-dental structures in the rat]

In collaboration with the Research Department on vitamins and nutrition of Hoffmann-Laroche Laboratories, an experiment has been conducted, in strictly controlled dietary conditions, to study the effects of a maternal deficiency in vitamin A on the cranio-dental development of rat fetuses and of young weanling rats. A minimal dose of 6 international units per day for 100 g of body weight was required by the mothers for the gestation evolution and a natural birth. Hypovitaminosis A induced, in the fetuses, after 21 intrauterine days, a generalized delay in growth and development proportional to the deficiency severity. In the cranial base and the toothgerms, the delay reached over two fetal days. No teratogenic action was noted. The troubles observed in 21 day old fetuses seemed to disappear in young rats, 21 days after natural parturition. This compensation seemed to be related to a prolonged gestation, proportional to the vitamin deficiency and equal to the growth delay observed at the 21 fetal day. Only modifications in the molars, consisting in coronal dimension and enamel mineral density changes were still observed.