The effects of electromagnetic field on distraction osteogenesis and new bony tissue were investigated. Twenty-five New Zealand rabbits were divided into an experimental (12 rabbits) and a control (13 rabbits) group. An osteotomy was performed on the right tibia in the diaphyseal region in both groups. The experimental group was exposed to a magnetic field of 50 Hz 1.0 mT for 3 hours a day for 13 weeks. The control group was kept in a similar environment but with no electromagnetic field. The distraction was continued until an increase of 10 mm was achieved. At weeks 4, 8, and 13, radiography, scintigraphy, and a biopsy were performed in both groups, and the results were statistically analyzed. The X-ray results were similar in both groups at all times. On the other hand while the scintigraphic and histopathological results were similar at weeks 4 and 13 in both groups, the osteoblastic activity was significantly greater in the experimental group at week 8 (p < 0.01). In conclusion an electromagnetic field increases the osteoblastic activity and osteogenesis, but has little effect during the remodeling phase.
Animals ; *Electromagnetic Fields ; Osteoblasts/physiology/radiation effects ; Osteogenesis/radiation effects ; *Osteogenesis, Distraction ; Osteotomy ; Rabbits

OBJECTIVETo investigate the effects of different-intensity sinusoidal electromagnetic fields (SEMFs) on bone mineral density (BMD) and histomorphometry in SD rats.

METHODSThirty female SD rats were randomly divided into three groups: group A (a control group), group B (0.1 mT group) and group C (0.6 mT group). The rats in group B and C were exposed to 50 Hz SEMFs 3 hours each day. However,the magnetic intensity was different between group B and group C:0.1 mT for group B and 0.6 mT for group C. After 8 weeks, all the animals were killed. Changes of BMD and histomorphometric properties were observed.

RESULTSCompared with group A, the BMD of whole body, femur and vertebrae of rats in group B increased significantly; the area percentage, number and width of bone trabeculae in vertebrae and femur of rats in group B were larger than those of group A; but the resolution of bone trabeculae of rats in group B was lower than that of group A. The trabecular number in group C rats were significantly decreased, compared with that in group A rats. The outcome of double fluorescence labeling in group B was found to be significantly different with that in group A. But the difference between rats in group A and C was not significant.

CONCLUSIONThis study demonstrates that 50 Hz 0.1 mT SEMFs can increase BMD, improve bone tissue microstructure and, promote bone formation.

Animals ; Bone Density ; radiation effects ; Electromagnetic Fields ; Female ; Lumbar Vertebrae ; pathology ; radiation effects ; Osteogenesis ; radiation effects ; Rats ; Rats, Sprague-Dawley ; Tibia ; pathology ; radiation effects

To study the genic and non-genic regulation of 50 Hz 0.6 mT pulsed electromagnenic fields (PEMF) on rat calvarial osteoblasts (ROB) differentiation.ROBs were achieved by enzyme digestion, and treated with 50 Hz 0.6 mT PEMFs for 1.5 hours after subculture. The alkaline phosphatase (ALP) activity, mRNA transcription of ALP, Runx2 and OSX and protein expression of Runx2 and OSX were detected at 0, 3, 6, 9 and 12 hours after PEMF treatment.The ALP activity at 3 hours after treatment was significantly higher than that in the control(<0.01), while the mRNA transcription of ALP began to increase at 6 hours after treatment. The mRNA transcription of Runx2 increased immediately after treatment and regressed at 6 hours, then increased again. The protein expression of it corresponded but with a little lag. The mRNA transcription of OSX also raised instantly after treatment, then returned to the level of control at 6 hours, and lower than control at 12 hours significantly. The protein expression of it also corresponded but with a bit delay.There are genic regulation for the protein expression of Runx2 and OSX, and non-genic regulation for the ALP activity on the process of 50 Hz 0.6 mT PEMFs prompts ROBs differentiation.
Alkaline Phosphatase ; metabolism ; radiation effects ; Animals ; Cell Differentiation ; genetics ; radiation effects ; Cells, Cultured ; Core Binding Factor Alpha 1 Subunit ; metabolism ; radiation effects ; Electromagnetic Fields ; Osteoblasts ; chemistry ; radiation effects ; Osteogenesis ; genetics ; radiation effects ; Rats ; Transcription Factors ; metabolism ; radiation effects

This study examined the osteogenic effect of electromagnetic fields (EMF) under the simulated in vivo conditions. Rat bone marrow mesenchymal stem cells (BMSCs) and rat osteoblasts were co-cultured and exposed to 50 Hz, 1.0 mT EMF for different terms. Unexposed single-cultured BMSCs and osteoblasts were set as controls. Cell proliferation features of single-cultured BMSCs and osteoblasts were studied by using a cell counting kit (CCK-8). For the co-culture system, cells in each group were randomly chosen for alkaline phosphatase (ALP) staining on the day 7. When EMF exposure lasted for 14 days, dishes in each group were randomly chosen for total RNA extraction and von Kossa staining. The mRNA expression of osteogenic markers was detected by using real-time PCR. Our study showed that short-term EMF exposure (2 h/day) could obviously promote proliferation of BMSCs and osteoblasts, while long-term EMF (8 h/day) could promote osteogenic differentiation significantly under co-cultured conditions. Under EMF exposure, osteogenesis-related mRNA expression changed obviously in co-cultured and single-cultured cells. It was noteworthy that most osteogenic indices in osteoblasts were increased markedly after co-culture except Bmp2, which was increased gradually when cells were exposed to EMF. Compared to other indices, the expression of Bmp2 in BMSCs was increased sharply in both single-cultured and co-cultured groups when they were exposed to EMF. The mRNA expression of Bmp2 in BMSCs was approximately four times higher in 8-h EMF group than that in the unexposed group. Our results suggest that Bmp2-mediated cellular interaction induced by EMF exposure might play an important role in the osteogenic differentiation of BMSCs.
Alkaline Phosphatase ; biosynthesis ; Animals ; Bone Marrow Cells ; cytology ; radiation effects ; Cell Differentiation ; genetics ; radiation effects ; Cell Proliferation ; radiation effects ; Coculture Techniques ; Electromagnetic Fields ; Mesenchymal Stromal Cells ; radiation effects ; Osteoblasts ; radiation effects ; Osteogenesis ; genetics ; radiation effects ; Rats

OBJECTIVE: To explore the effects of low level laser irradiation (LLLI) on the osteogenic capacity of three-dimensional (3D) structure by 3D bio-printing construct used human adipose-derived stem cells (hASCs) as seed cells. METHODS: Using hASCs as seed cells, we prepared sodium alginate/gelatin/hASCs 3D bio-printing construct, and divided them into four groups: PM (proliferative medium), PM+LLLI, OM (osteogenic medium) and OM+LLLI, and the total doses of LLLI was 4 J/cm². Immunofluorescence microscopy was used to observe the viability of the cells, and analyze the expression of the osteogenesis-related protein Runt-related transcription factor 2 (Runx2) and osteocalcin (OCN). RESULTS: The 3D constructs obtained by printing were examined by microscope. The sizes of these 3D constructs were 10 mm×10 mm×1.5 mm. The wall thickness of the printed gelatin mold was approximately 1 mm, and the pores were round and had a diameter of about 700 μm. The cell viability of sodium alginate/gelatin/hASCs 3D bio-printing construct was high, and the difference among the four groups was not significant. On day 7, the expression of OCN from high to low was group OM+LLLI, PM+LLLI, OM and PM. There were significant differences among these groups (P<0.01), but there was no significant difference between group PM+LLLI and OM. On day 14, the expression of OCN in each group was higher than that on day 7, and there was no significant difference between group OM+LLLI and OM. The expression of Runx2 in group OM+LLLI was more than 90%, significantly higher than that in group OM (P<0.01). But the expression of Runx2 in group PM+LLLI and OM+LLLI were significantly lower than that in the non-irradiated groups. The expression of osteogenesis-related protein Runx2 and OCN were higher in OM groups than in PM groups. Furthermore, the irradiated groups were significantly higher than the non-irradiated groups. CONCLUSION LLLI does not affect the cell viability of sodium alginate/gelatin/hASCs 3D bio-printing construct, and may promote the osteogenic differentiation of hASCs.
Adipocytes/radiation effects* ; Alginates ; Cell Differentiation ; Cell Proliferation ; Gelatin ; Humans ; Lasers ; Osteogenesis ; Printing, Three-Dimensional ; Stem Cells/radiation effects*

The present research was to investigate the time effect of sinusoidal electromagnetic fields (SEMFs) at different exposure time on the proliferation and differentiation of osteoblasts (OB) in vitro. The newborn rat calvarial OB were isolated by enzyme digestion and divided randomly into 7 groups after one passage. The exposure times of the SEMFs were 0.5 h, 1.0 h, 1.5 h, 2.0 h, 2.5 h and 3.0 h, respectively, and the frequency was 50 Hz. The cells were exposed in the SEMFs of 1.8 mT. Those without SEMFs exposure were used as the control group. They were observed under the contrast phase microscope each day. After 48 h, cell proliferation was assayed by MTT method. The alkaline phosphatase (Alkaline Phosphatase, ALP) activities were measured after the exposure of SEMFs for 3 d, 6 d, 9 d and 12 d, respectively. The calcified nodules were stained by Alizarin Bordeaux after 10 d. The cells exposed in the SEMFs were arranged in Spiral appearance after 8 d. The SEMFs exposure time at 2.0 h, 2.5 h and 3.0 h significantly inhibited cell proliferation (P < 0.01) and 0.5 h, 1.0 h, 1.5 h groups more significantly than control groups (P < 0.05). When the 3 d, 6 d and 12 d the ALP activities of the 0.5 h, 1.0 h, 1.5 h and 2.0 h, times group were significantly higher than those in the control group (P < 0.05), and after 9 d the 1.0 h, 1.5 h and 2.0 h activity of ALP higher significantly than control and other groups (P < 0.01). Other groups had no effect on the ALP activity. Alizarin Bordeaux staining result showed the amounts of calcified nodules 1.0 h, 1.5 h and 2.0 h higher than control groups. The SEMFs at 50 Hz, 1.8 mT different time exposure groups inhibits the proliferation of OB, but they enhances the maturation and mineralization of the OB and SEMFs at 1.8 mT of the 1.5 h has the strongest activity.
Animals ; Animals, Newborn ; Calcification, Physiologic ; radiation effects ; Cell Differentiation ; radiation effects ; Cell Proliferation ; radiation effects ; Cells, Cultured ; Electromagnetic Fields ; Osteoblasts ; cytology ; Osteogenesis ; Rats ; Rats, Sprague-Dawley

Animals ; Catalysis ; Cell Adhesion ; drug effects ; radiation effects ; Humans ; Hydrophobic and Hydrophilic Interactions ; Osseointegration ; drug effects ; radiation effects ; Osteoblasts ; cytology ; drug effects ; radiation effects ; Osteogenesis ; drug effects ; radiation effects ; Photochemical Processes ; Surface Properties ; radiation effects ; Time Factors ; Titanium ; chemistry ; pharmacology ; radiation effects ; Ultraviolet Rays

To study the effects of 1.8 mT sinusoidal electromagnetic fields of different frequencies on bone mineral density (BMD) and biomechanical properties in young rats.A total of 32 female SD rats (6-week-old) were randomly divided into 4 groups (8 in each):control group, 10 Hz group, 25 Hz group and 40 Hz group. The experimental groups were given 1.8 mT sinusoidal electromagnetic field intervention 90 min per day. The whole body BMD of rats was detected with dual-energy X-ray absorptiometry after 4 and 8 weeks of intervention. After 8 weeks of intervention, all rats were sacrificed, and the BMD of femur and lumbar vertebra, the length and diameter of femur, the width between medial and lateral malleolus were measured. Electronic universal material testing machine was used to obtain biomechanical properties of femur and lumbar vertebra, and micro CT scan was performed to observe micro structures of tibial cancellous bone.Compared with the control group, rats in 10 Hz and 40 Hz groups had higher whole body BMD, BMD of femur, maximum load and yield strength of femur, as well as maximum load and elastic modulus of lumbar vertebra (all<0.05). But no significant differences in the length and diameter of femur, and the width between medial and lateral malleolus were observed between control group and experimental groups (all>0.05). Micro CT scan showed that the trabecular number and separation degree, bone volume percentage were significantly increased in 10 Hz and 40 Hz groups (all<0.01). Rats in 25 Hz group also had higher BMD and better in biomechanical properties than control group, but the differences were not statistically significant (all>0.05).10 and 40 Hz of 1.8 mT sinusoidal electromagnetic field can significantly improve the bone density, microstructure and biomechanical properties in young rats.
Absorptiometry, Photon ; Animals ; Biomechanical Phenomena ; radiation effects ; Bone Density ; radiation effects ; Cancellous Bone ; growth & development ; radiation effects ; Electromagnetic Fields ; Female ; Femur ; growth & development ; radiation effects ; Lumbar Vertebrae ; growth & development ; radiation effects ; Magnetic Field Therapy ; methods ; Osteogenesis ; radiation effects ; Rats ; Rats, Sprague-Dawley ; Tibia ; growth & development ; radiation effects

To investigate the effect of irradiation on the quantity and osteogenesis potential of BMMSCs and to explore the response of them in the irradiation stress and its contribution to long-term effects of radiation-induced bone and hematologic injury, a total body irradiation (TBI) murine model was adopted. The number of CFU-F and cell cycle profile of BMMSCs were analyzed at different time points before and after TBI. Osteogenic differentiation was evaluated by Von Kossa staining, expressions of osteogenesis-related genes and transcriptional coactivator with PDZ-binding motif (TAZ) were detected by real-time RT-PCR. The results showed that the number of CFU-F decreased greatly at day 28 after TBI. At day 3 after TBI, more cells entered cell cycle and the osteogenesis potential was greatly enhanced followed by recovery of cell cycle distribution and significant defect in osteoblast differentiation respectively, meanwhile the expression of TAZ was changed. It is concluded that TBI results in the reduction of bone marrow mesenchymal stem/progenitor cell pool and alters the osteogenesis potential of BMMSCs, which is related to the change of TAZ expression.
Animals ; Bone Marrow Cells ; cytology ; radiation effects ; Colony-Forming Units Assay ; Dose-Response Relationship, Radiation ; Male ; Mesenchymal Stromal Cells ; cytology ; radiation effects ; Mice ; Mice, Inbred C57BL ; Osteogenesis ; radiation effects ; Whole-Body Irradiation

Retaining or improving periodontal ligament (PDL) function is crucial for restoring periodontal defects. The aim of this study was to evaluate the physiological effects of low-power laser irradiation (LPLI) on the proliferation and osteogenic differentiation of human PDL (hPDL) cells. Cultured hPDL cells were irradiated (660 nm) daily with doses of 0, 1, 2 or 4 J⋅cm(-2). Cell proliferation was evaluated by the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay, and the effect of LPLI on osteogenic differentiation was assessed by Alizarin Red S staining and alkaline phosphatase (ALP) activity. Additionally, osteogenic marker gene expression was confirmed by real-time reverse transcription-polymerase chain reaction (RT-PCR). Our data showed that LPLI at a dose of 2 J⋅cm(-2) significantly promoted hPDL cell proliferation at days 3 and 5. In addition, LPLI at energy doses of 2 and 4 J⋅cm(-2) showed potential osteogenic capacity, as it stimulated ALP activity, calcium deposition, and osteogenic gene expression. We also showed that cyclic adenosine monophosphate (cAMP) is a critical regulator of the LPLI-mediated effects on hPDL cells. This study shows that LPLI can promote the proliferation and osteogenic differentiation of hPDL cells. These results suggest the potential use of LPLI in clinical applications for periodontal tissue regeneration.
Adenine ; analogs & derivatives ; pharmacology ; Adenylyl Cyclase Inhibitors ; Alkaline Phosphatase ; analysis ; genetics ; radiation effects ; Anthraquinones ; Bone Morphogenetic Protein 2 ; genetics ; Calcium ; metabolism ; radiation effects ; Cell Culture Techniques ; Cell Differentiation ; radiation effects ; Cell Line ; Cell Proliferation ; radiation effects ; Coloring Agents ; Core Binding Factor Alpha 1 Subunit ; genetics ; Cyclic AMP ; antagonists & inhibitors ; radiation effects ; Gene Expression ; radiation effects ; Humans ; L-Lactate Dehydrogenase ; analysis ; Lasers, Semiconductor ; Low-Level Light Therapy ; instrumentation ; Osteocalcin ; genetics ; Osteogenesis ; genetics ; radiation effects ; Periodontal Ligament ; cytology ; radiation effects ; Radiation Dosage ; Real-Time Polymerase Chain Reaction ; Reverse Transcriptase Polymerase Chain Reaction ; Tetrazolium Salts ; Thiazoles