Rats subjected to saline (A, D, G, J, M, P,S); rats subjected to ligation (B, E, H, K, N, Q,T); rats subjected to ligation and treated with AZT (5 mg/kg) (C, F, I, L, O, R,U). Images are shown at 40× magnification. Bar = 100 µm. Arrow indicates high or moderate labeling in the periodontal ligament or the alveolar bone. Asterisk indicates mild or moderate labeling in the periodontal ligament or the alveolar bone. Triangle and asterisk indicate mild labeling of OPG in osteoclasts. Triangle and arrow indicate high labeling of osteoclasts. Triangle indicates intense labeling of Cathepsin K on alveolar bone. Asterisk and triangle indicate mild labeling of cathepsin K on alveolar bone.