Histochemical examination of osteoblastic activity in op/op mice with or without injection of recombinant M-CSF

Abstract

Osteopetrotic (op/op) mice do not exhibit bone remodeling because of defective osteoclast formation caused by the depletion of macrophage colony-stimulating factor (M-CSF). In the present study, we investigated tibial bones of op/op mice with or without prior injections of M-CSF to determine whether osteoclast formation and subsequent bone resorption could activate osteoblasts, which is known as a "coupling" phenomenon. In op/op mice, no osteoclasts were present, but the metaphyseal osteoblasts adjacent to the growth plate cartilage seemed to be active, revealing an intense alkaline phosphatase (ALPase) immunoreactivity. Consequently, primary trabecular bones were extended continuously to the diaphysis, indicating that bone modeling is well achieved in op/op mice. In contrast with the metaphysis, most of the diaphyseal osteoblasts were flattened and showed weak ALPase activity, and, as a result, they seemed to be less active. Osteopontin (OPN) was localized slightly at the interface between bone and cartilage matrices of the primary trabeculae. In contrast, in op/op mice injected with M-CSF, tartrate-resistant acid phosphatase-positive osteoclasts appeared, resorbing trabecular bones of the diaphyseal region. The diaphyseal osteoblasts in the vicinity of the active osteoclasts were cuboidal and exhibited strong ALPase immunoreactivity. OPN was observed not only at the bone-cartilage interface, but also significantly on the resorption lacunae beneath the bone-resorbing osteoclasts. These observations indicate that the activation of diaphyseal osteoblasts appears to be coupled with osteoclast formation and subsequent osteoclastic bone resorption. Alternatively, the metaphyseal osteoblasts at the chondro-osseous junction seemed to be less affected by osteoclastic activity.

Effects of drug discontinuation after short-term daily alendronate administration on osteoblasts and osteocytes in mice

“…Without osteoclasts, osteoblastic population, osteoblastic bone formation and bone mineralization are markedly diminished in op/op mice, which lack the macrophage colony-stimulating factor [12,13]. One of our studies demonstrated that cell coupling between osteoclasts and preosteoblasts must take place for the parathyroid hormone-driven bone anabolic effect to occur [14].…”

“…In vivo animal studies have shown that bisphosphonate administration negatively affects mineral apposition rate, which suggests reduced osteoblast activity [15][16][17][18]. This may be due to hindrances in the "coupling phenomenon", the partnership with osteoclasts that seems to be necessary for osteoblastic activity during bone remodeling [12][13][14]. High-dose bisphosphonate administration disrupts the coupling between osteoclastic bone resorption and osteoblastic bone formation [34], and several in vivo studies have shown the effects of such disruption of cell coupling on osteoblasts [17,35].…”

Renal macrophage migration and crystal phagocytosis via inflammatory-related gene expression during kidney stone formation and elimination in mice: Detection by association analysis of stone-related gene expression and microstructural observation

“…Mice with absent osteoclasts, known as op/op mice, have induced failure of bone remodeling and exhibit osteopetrosis by reduced bone resorption. (18) Although no report has discussed the relationship between M-CSF and kidney stone formation, granulocyte-macrophage colony-stimulating factor (GM-CSF) could be involved in hypercalciuria and bone mineral loss in calcium kidney stone formation via peripheral blood monocyte activation. (19) Cxcl1 encodes chemokine (C-X-C motif) ligand 1 (CXCL1), known as growth-related oncogene 1 (GRO1), which could enhance the adhesion of monocytes to matrix protein, (20) and is involved in the atherogenic recruitment of monocytes.…”

“…However, the precise function of macrophages in kidney stone formation and elimination could not be determined, and the possibility that we observed renal responses to crystal formation remains. To confirm the role of macrophages in kidney stone formation, an in vivo study using op/op mice (18) or an in vitro study using cultured renal tubular cells and macrophages to detect the paracrine systems between cells is necessary. Moreover, the mechanism of removing intratubular crystals to the interstitial area should be investigated in the future.…”

<b>Histochemical assessment for osteoblastic activity coupled with dysfunctional osteoclasts in </b><i><b>c-src</b></i><b> deficient </b><b>mice </b>

“…We have previously reported that cell coupling with osteoclasts in vivo is necessary for preosteoblastic differentiation into mature osteoblasts to deposit new bone in response to parathyroid hormone (21). Consistently, op/op mice, an- other mouse model lacking osteoclasts (9,18,19,22) revealed the extremely-reduced osteoblastic activity in long bones (26), and defective bone mineralization (30). Taken together, the presence of osteoclasts is important for cell coupling to activate osteoblastic cells in bone remodeling sites in vivo.…”