Photomicrographs of the thyroid of rabbits of PTU-treated group (T1) showed hypothyroid changes and distortion in its architecture that characterized by decrease in the size of most follicles (Dashed black arrow) with drop in or lack in the amount of colloid, and increased thickness of follicular lining epithelium (Red arrow). (A) H&E 10X. (B)H&E 40X.