Objectives
Cleft lip and palate (CL/P) are common congenital orofacial anomalies. Autogenous iliac bone grafting closes alveolar cleft defects but requires surgical intervention. Mesenchymal stem cell culture supernatant can regenerate tissues via paracrine activity. However, little is known about the bone‐regenerative effects of stem cells from human exfoliated deciduous teeth (SHED) and conditioned media (CM). Our aim was to address this.
Materials and methods
Stem cells were isolated from primary tooth pulp and cultured. Defects were made in calvariae of immunodeficient mice and implanted with stem cell‐ or CM‐containing atelocollagen. Regenerated bone was analysed by microcomputed tomography, haematoxylin–eosin and Masson's trichrome staining. Vascular endothelial growth factor, CD31 and CD34 expression were confirmed by immunohistochemistry, and the presence of several proteins and growth factors was verified in SHED‐CM.
Results
Bone regeneration was enhanced in defects treated with stem cells and CM compared to that in controls 8 weeks after transplantation. Mature bone formation and angiogenesis were confirmed with CM but not with stem cells or in controls. Secretome analysis using multiple cytokine assays revealed that SHED‐CM contained tissue‐regenerating factors with roles in angiogenesis and osteogenesis.
Conclusion
CM non‐invasively regenerate bone and might be effective to reconstruct alveolar clefts in CL/P patients.
The effects of flow on the changes of electrical resistivity and light-scattering characteristics of blood are experimentally and theoretically discussed. Studies indicate that most erythrocytes deform and orient themselves in the flow direction when blood flows in a conduit. Such oriented blood shows anisotropic properties. Anisotropic electrical resistivity of flowing blood is measured in three rectangular directions with a measurement cell of coaxial cylindrical type. From these experimental results, the orientation and deformation of erythrocytes are discussed. The orientation ratio and the deformation are calculated using a simplified spheroidal model of an erythrocyte. Calculated results show that the fractions of erythrocytes with their short axis parallel to each direction and the equivalent axis ratio for a simplified spheroidal model change with the shear rate of flow.
Laser irradiation activates a range of cellular processes and can promote tissue repair. Here, we examined the effects of high-frequency near-infrared (NIR) diode laser irradiation on the proliferation and migration of mouse calvarial osteoblastic cells (MC3T3-E1). MC3T3-E1 cells were cultured and exposed to high-frequency (30 kHz) 910-nm diode laser irradiation at a dose of 0, 1.42, 2.85, 5.7, or 17.1 J/cm. Cell proliferation was evaluated with BrdU and ATP concentration assays. Cell migration was analyzed by quantitative assessment of wound healing using the Incucyt ZOOM system. In addition, phosphorylation of mitogen-activated protein kinase (MAPK) family members including p38 mitogen-activated protein kinase (p38), stress-activated protein kinase/Jun-amino-terminal kinase (SAPK/JNK), and extracellular signal-regulated protein kinase (ERK)1/2) after laser irradiation was examined with western blotting. Compared to the control, cell proliferation was significantly increased by laser irradiation at a dose of 2.85, 5.7, or 17.1 J/cm. Laser irradiation at a dose of 2.85 J/cm induced MC3T3-E1 cells to migrate more rapidly than non-irradiated control cells. Irradiation with the high-frequency 910-nm diode laser at a dose of 2.85 J/cm induced phosphorylation of MAPK/ERK1/2 15 and 30 min later. However, phosphorylation of p38 MAPK and SAPK/JNK was not changed by NIR diode laser irradiation at a dose of 2.85 J/cm. Irradiation with a high-frequency NIR diode laser increased cell division and migration of MT3T3-E1 cells, possibly via MAPK/ERK signaling. These observations may be important for enhancing proliferation and migration of osteoblasts to improve regeneration of bone tissues.
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