SKELETAL GROWTH CHANGES ASSOCIATED WITH PRENATALLY INDUCED HYPOTHYROIDISM AND SIMULTANEOUS THYROXIN TREATMENT IN ALBINO RAT.
Abd El-Rahman El-Shahat
Department of Anatomy , Faculty of Medicine, Cairo University
This study was carried to evaluate the effect of carbimazole induced hypothyroidism and thyroxine replacement on axial and appendicular skeletal growth in prenatally treated albino rats. Experimental pregnant female albino rats were treated with carbimazole and carbimazole plus thyroxine from the 10th day of pregnancy till parturition.The pups born to these treated mothers were cleaned, weighed and measured for CR length and left with their mothers till 10th post natal day. These pups were weighed and measured again for CR length and then were sacrificed, fixed and processed to demonstrate the bony and cartilaginous parts. The ulna and tibia of both sides were measured for intact bone length & diameter and the data compared. The reduction in length and circumference observed. In ulna it was 13.67%, & 18.18% and in tibia it was 24.87%, 24.60% in carbimazole treated group respectively, while in carbimazole plus thyroxin treated group the reduction in length & circumference of ulna was 5.08% & 6.36% and in tibia it was 3.09% & 3.17% respectively when compared to their age matched controls. The reduction in the CR length (axial skeleton) of the pups born to carbimazole treated mothers was 8.77% and of those born to carbimazole plus thyroxin treated mothers was 3.20%. The reduction in the weight of the pups born to carbimazole treated mothers was 11.29% and of those born to carbimazole plus thyroxin treated mothers was 2.96%. The results show that the prenatal hypothyroidism affects the general weight gain, crown rump length (axial skeleton) and endochondral as well as periosteal bone growth of appendicular skeleton.