Influence of 1,25(OH)
therapy on trabecular bone volume, osteoid volume and cellular bone turnover parameters (secondary spongiosa of the right tibia head – arthritic joint) in AIA of the rat. In comparison to healthy controls, vehicle-treated AIA (AIA + vehicle) was associated with a highly significant decrease of trabecular bone volume (A), a significant increase in osteoid-covered surface (D) and a numerical increase in osteoid volume (B) and osteoid-covered surface with osteoblasts (E). 1,25(OH)2D3 therapy completely inhibited AIA-induced bone loss and resulted in a significant increase of trabecular bone volume (A) and osteoid volume (B) in comparison to vehicle-treated AIA and healthy controls. Osteoid-covered surface with osteoblasts was reduced by 1,25(OH)2D3 treatment to values of healthy controls (E). Osteoid-covered surface remained increased in comparison to healthy animals (D). Resorption surface with osteoclasts was not significantly influenced by AIA and by 1,25(OH)2D3 therapy (C). **p < 0.01; *p < 0.05 vs. AIA + vehicle; +++p < 0.001; ++p < 0.01; +p < 0.05 vs. healthy controls.