The Possible Role of Neutrophils in the Induction of Osteoclastogenesis
Activated cPMNs do not stimulate osteoclastogenesis in cocultures with osteoclast precursors. Nuclei are stained with DAPI (visualized in blue), and TRACP expression is shown in green. Preosteoclasts (monocytes) were cultured for 10 days with RANKL and M-CSF. (a) TRACP-positive, multinucleated cells were formed (depicted by arrows). (b) Monocytes were cultured with unstimulated cPMNs. (c) Monocytes were cultured with stimulated cPMNs (IL-6, 100 ng/mL for 48 hours) and did not differentiate into TRACP-positive multinucleated cells. (d) Monocytes were cocultured with TNF-α-stimulated cPMNs (50 ng/mL for 24 hours) and did not differentiate into osteoclasts. (e) Monocytes were cocultured with TNF-α-stimulated cPMNs (50 ng/mL, 48 hours) and did not differentiate into osteoclasts. Representative micrographs of three independent experiments are shown. Scale bars represent 200 μm.