NEURAL-TUBE DEFECTS - AN EXPERIMENTAL-MODEL IN THE FETAL-RAT

We report on our experience in the experimental induction of Neural Tu be Defects (NTD) in the foetal rat by maternal administration of retin oic acid. The teratogen diluted in olive oil was administered in a sin gle intragastric dose (125 mg/kg body weight) to pregnant rats (n = 31 ) on the 10th day of gestation. Pure olive oil was given to control fa ts (n = 9). The foetuses were recovered by caesarian section on the 20 th day and prepared for morphological investigation. We have studied 2 01 experimental and 82 control animals. There were NTD in 36.3% of exp erimental foetuses and none in the control ones. Sacral dysraphism was the most frequent defect but we also observed Arnold Chiari malformat ions and crowding of the bony limits by an enlarged neural axis. Other associated malformations found were: craneofacial (78.1%), caudal (80 %), anorectal (31.4%) and limb defects (89.5%). This simple and inexpe nsive model may allow us to gain a better knowledge of the biology in the foetus with NTD.