Volume 39, March 2023, Pages 43-54Author links open overlay panelAbstractObjective

To investigate the therapeutic effects of static magnetic field (SMF) and its regulatory mechanism in the repair of osteoarthritic cartilage.

Methods

Fourteen-week-old female C57BL/6 mice were randomly divided into the sham operation group and the osteoarthritis (OA) groups with and without SMF application. SMF was applied at 200 ​mT for two consecutive weeks. Changes in knee cartilage were examined by histomorphometry, and the chondrogenesis and migration of endogenous stem cells were assessed. The expression of SRY-related protein 9 (SOX9), Collagen type II (COL2), matrix metallopeptidase 13 (MMP13), stromal cell-derived factor 1/C-X-C chemokine receptor type 4 (SDF-1/CXCR4), Piezo1 and other genes was evaluated, and the mechanism of SMF's action was tested using the CXCR4 inhibitor, AMD3100, and Piezo1 siRNA.

Results

SMF significantly decreased the OARSI scores after induction of OA. SMF was beneficial to chondrogenesis by elevating SOX9. In the OA mouse model, an increase in MMP13 with a decrease in COL2 led to the destruction of the cartilage extracellular matrix, which was suppressed by SMF. SMF promoted the migration of cartilage-derived stem/progenitor cells and bone marrow-derived mesenchymal stem cells (MSCs). It increased SDF-1 and CXCR4, while the CXCR4 inhibitor significantly suppressed the beneficial effects of SMF. The application of Piezo1 siRNA inhibited the SMF-induced increase of CXCR4.

Conclusion

SMF enhanced chondrogenesis and improved cartilage extracellular matrices. It activated the Piezo1-mediated SDF-1/CXCR4 regulatory axis and promoted the migration of endogenous stem cells. Collectively, it attenuated the pathological progression of cartilage destruction in OA mice.

The Translational potential of this article

The findings in this study provided convincing evidence that SMF could enhance cartilage repair and improve OA symptoms, suggesting that SMF could have clinical value in the treatment of OA.

Keywords

Osteoarthritis

Static magnetic field

Mesenchymal stem cells

Chondrogenesis

SDF-1/CXCR4

Piezo1

AbbreviationsBMSCs

Bone marrow mesenchymal stem cells

CD105

Endothelial glycoprotein

CD146

Melanoma cell adhesion molecule

CD166

Activated leukocyte adhesion molecule

CSPCs

Cartilage-derived stem/progenitor cells

CXCR4

C-X-C chemokine receptor type 4

MMP13

Matrix metallopeptidase 13

MSCs

Mesenchymal stem cells

OARSI

Osteoarthritis Research Society International

SDF-1

Stromal cell-derived factor 1

SOX9

SRY-related protein 9

TAC

Total articular cartilage

Ping Zhang

© 2022 The Authors. Published by Elsevier B.V. on behalf of Chinese Speaking Orthopaedic Society.