title: Low-intensity pulsed ultrasound regulates proliferation and differentiation of osteoblasts through osteocytes.
abstract: Low-intensity pulsed ultrasound (LIPUS) has been used as a safe and effective modality to enhance fracture healing. As the most abundant cells in bone, osteocytes orchestrate biological activities of effector cells via direct cell-to-cell contacts and by soluble factors. In this study, we have used the osteocytic MLO-Y4 cells to study the effects of conditioned medium from LIPUS-stimulated MLO-Y4 cells on proliferation and differentiation of osteoblastic MC3T3-E1 cells. Conditioned media from LIPUS-stimulated MLO-Y4 cells (LIPUS-Osteocyte-CM) were collected and added on MC3T3-E1 cell cultures. MC3T3-E1 cells cultured in LIPUS-Osteocyte-CM demonstrated a significant inhibition of proliferation and an increased alkaline phosphatase activity. The results of PGE(2) and NO assay showed that LIPUS could enhance PGE(2) and NO secretion from MLO-Y4 cells at all time points within 24h after LIPUS stimulation. We conclude that LIPUS regulates proliferation and differentiation of osteoblasts through osteocytes in vitro. Increased secretion of PGE(2) from osteocytes may play a role in this effect.
authors.affiliation: State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Li
authors.forename: Zheng
authors.initials: Z
authors.lastname: Yang
authors.forename: Hai
authors.initials: H
authors.lastname: Zhang
authors.forename: Wenchuan
authors.initials: W
authors.lastname: Chen
authors.forename: Mengshi
authors.initials: M
authors.lastname: Chen
authors.forename: Zhimin
authors.initials: Z
authors.lastname: Zhu
mesh_terms: D000818:Animals; D002454:Cell Differentiation; D002460:Cell Line; D049109:Cell Proliferation; D017077:Culture Media, Conditioned; D015232:Dinoprostone / Q000378:metabolism; D051379:Mice; D010006:Osteoblasts / Q000502:physiology*; D010011:Osteocytes / Q000378:metabolism / Q000502:physiology*; D010012:Osteogenesis; D014465:Ultrasonics
chemical_list: D017077:Culture Media, Conditioned; D015232:Dinoprostone