Increase in the potential of osteoblasts to support bone resorption by osteoclasts in vitro in response to roughness-of bone surface

The development of the potential of osteoblasts to support bone resorption by osteoclasts in response to roughness on bone slices was examined in the co-incubation cell system of immature osteoclasts and osteoblastic cells. T he immature osteoclasts, which need alkaline phospatase (ALP)-positive oste oblastic cells for bone resorption, were generated in mouse spleen cultures with I, 25-dihydroxy-vitamin D-3 and prostaglandin E-2. ALP-negative osteo blastic cells from mouse calvaria were incubated on rough surfaced bone sli ces for 3 days. The number of ALP-posirtve cells increased greatly on the r ough surface, but little on the smooth surface. When immature osteoclasts w ere added and incubated for 1 more day, the resorption pit number and the t otal pit areas on the smooth surface were not much different from those bef ore incubation but were approximately four times higher on the rough surfac e.