Photomicrograph of lymphatic follicle of red pulp in spleen. The expression of anti-CD68 primary antibody (arrow) has shown (A) positive expression in control group, (B) weak expression in hypothyrodism group, (C) moderate expression in the SC-SeNPs group, (D) strong expression in the levothyroxine group, and (E) strong expression in the SC-SeNPs+levothyroxine group. Hematoxylin & DAB. 400x