[Effect of Pulsed Electromagnetic Fields on Osteogenic Differentiation and Wnt/ß-catenin Signaling Pathway in Rat Bone Marrow Mesenchymal Stem Cells].

OBJECTIVE: To investigate the effect of pulsed electromagnetic tields (FEMFs) on osteogemc differentiation and Wnt/ß-catenin signaling pathway in rat bone marrow mesenchymal stem cells (BMSCs). METHODS: Rat BMSCs were isolated and the passage 3 cells were divided into 3 groups. Cells were cultured in LG-DMEM complete medium for 1 d to ensure fully adherent. Then, change the medium. Cells were maintained in complete medium (Control group) or in osteo-induction medium (OM group). The cells in PEMFs group were cultured in complete medium and exposed to 8 Hz, 3. 8 mT PEMF stimulation for 40 min/d. The intervention lasted for 21 d. Cell proliferation activity was determined by using MTT. The effects of PEMF onosteogenic differentiation were assessed by ALP and Alizarin Red S staining. Various osteoblast-relevant genes and genes of Wnt/ß-catenin signaling were analyzed by quantitative real-time RT-PCR. RESULTS: We. found that OM could significantly promote the proliferation of BMSC at 7 d, 14 d, 21 d (P<0. 05), but the effect was not obviously found in PEMFs group. For osteogenic differentiation, the positive rates of ALP or Alizarin Red S staining were detected higher in PEMFs/ OM group (P < 0. 05). Quantitative RT-PCR revealed PEMFs or OM could increase mRNA levels of Wnt1, Wnt3a, LRP5, ß-catenin, BMP-2, Runx2, ALP, OC at special time point (P<0. 05). Compared to OM group, PEMFs have a lower expression in each detection, but the trends were consistent. CONCLUSION: PEMFs (8 Hz, 3. 8 mT) could induce the osteogenic differentiation of rat BMSCs via activating Wnt/ß-catenin signaling pathway.

[Effects of whole body vibration on structural and functional remodeling of subchondral bones in rabbits with early osteoarthritis].

OBJECTIVE: To investigate the effects of whole body vibration therapy (WBVT) on structural and functional remodeling of subchondral bone in rabbits with early Osteoarthritis (OA). METHODS: Twenty-four adult rabbits received anterior cruciate ligament transaction (ACLT) to establish knee osteoarthritis model. The rabbits were randomly divided into two groups: ACLT group and WBVT+ ACLT group. The rabbits in the WBVT+ ACLT group received whole body vibration treatment (Frequency: 40 Hz; Amplitude: 2-4 mm; 40 min/d, 5 d/week, 4 weeks) two months after surgery. After interventions, the left femur and tibia of all rabbits were placed in a Micro-CT scanning system. The bone volume fraction (BVF), trabecular thickness (Tb. Th), trabecular spacing (Tb. Sp), trabecular number (Tb. N), volumetric BMD (vBMD), and tissue BMD (tBMD) of the bones of femoral condyle and tibia were analysed using three-dimensional reconstruction Micview V2.1.2 and ABA analysis software. Geomagic Studio 11.0 software were used to calculate modulus (EM), reaction force (RF) and average Von Miss stress (VMF). RESULTS: Higher levels of BVF, Tb. N, Tb. Th, EM, RF, VMF, vBMD and tBMD and lower levels of Tb. Sp were found in distal femora and tibia of the rabbits in the WBVT+ACLT group compared with the controls (P < 0.05). CONCLUSION: WBVT can effectively improve bone microstructure and mechanical properties of rabbits with early knee osteoarthritis.