A Model for the Study of Induced Skeletal Anomalies in Albino Rat Fetuses

Objective: This work aims at studying the phenytoin-induced skeletal anomalies in albino rat fetuses, using double stain for fetal rat skeleton with Alizarin red S and Alcian blue to be considered as a model for the study of induced skeletal anomalies. The study was done by a stereomicroscope. Design: In the present study stereomicroscope was used to study the double stained skeleton for rat albino rat fetuses in control and phenytointreated groups. Material and Methods: Forteen adult albino female rats weighing about 170–250 g were used in this study. Three female rats were mated with one male overnight. The female rats were examined for sperms in the vaginal smear next morning, and sperm positive ones were considered as 0.5 day pregnant. The pregnant rats were divided into two equal groups :(control and treated). In group-1 (control group), the rats were injected with an intraperitoneal (IP) dose of 0.3 ml physiological serum at 09:00 a.m. on the 8, 9 , and 10 th days of pregnancy. In group-2 (treated group), the rats were received an intraperitoneal (IP) dose of 25 mg/kg/day phenytoin diluted with physiological serum at 09:00 a.m. on the 8 , 9 , and 10 th days of the pregnancy. On the 20 th day of pregnancy, all rats were anaesthetize d by ether inhalation and the fetuses were removed by transversal abdominal incision then dissected carefully. All the fetuses had been weighed using a scale and the crown-rump lengths were measured by a ruler. The fetuses were sacrificed with ether and examined for any gross external malformation. A number of 84 fetuses (44 from the group-1 and 40 from the group-2) were taken for the staining process, using Alizarin red S and Alcian blue stains. Results: Out of the 40 fetuses of phenytoin-treated group, no ossification signs appeared in some skull bones. Also, ossification was fine in other bones. Costal separation and costal angulation anomalies were observed in some fetuses of the treated group. No ossification was determined in the radius and the ulna of five fetuses. As for the metacarpal bones, no ossification was present in some of the metacarpal bones of four fetuses. Deficiency was also seen in the cartilage drafts of the metacarpal bones and phalanges in four fetuses. No ossification was determined in the coxal bones of four fetuses of this group. Tibia and fibula in 6 fetuses were completely cartilaginous in nature. No ossification was observed in the metatarsal bone drafts of one fetus. None of the phalanges of the foot of this fetus was ossified. Deficiency was also seen in the cartilage drafts of the phalanges. The mean value of the weights and lengths of the treated fetuses showed a highly significant difference as compared to control fetuses. Conclusion: Based on this study it can be concluded that phenytoin is a teratogenic substance, even with the lower doses, on the bone development of rats. [Metwally A. Mansoor, Aml S. Swilam, Maha M. Abdul Rahman and Mohamad A. Sabry. A Model for the Study of Induced Skeletal Anomalies in Albino Rat Fetuses. J Am Sci 2014;10(2):181-190]. (ISSN: 1545-1003). http://www.jofamericanscience. org. 27