Protective effects of pulsed electromagnetic field therapy attenuates autophagy and apoptosis in osteoporotic osteoarthritis model rats by activating PPARγ

ABSTRACT

Osteoporotic osteoarthritis (OPOA) is a specific phenotype of OA with high incidence and severe cartilage damage. This study aimed to explore the protective efficacy of PEMF on the progression of OPOA and observed the effects of PEMF on PPARγ, autophagy- and apoptosis-related proteins in OPOA rats. Rats were randomly divided into three groups: control group, OPOA group, and PEMF group (n = 6). One week after surgery, the rats in PEMF group were subjected to PEMF (3.82 mT, 8 Hz, 40 min/day and 5 day/week) for 12 weeks. Results showed that PEMF retarded cartilage degeneration and bone loss, as evidenced by pathological staining image, decreased MMP-13 expression and increased bone mineral density. PEMF inhibited the serum levels of inflammatory cytokines, and the expressions of caspase-3 and caspase-8, while upregulated the expression of PPARγ. Moreover, PEMF significantly improved the autophagy disorders, represented by decrease expressions of Beclin-1, P62, and LC3B. The research demonstrates that PEMF can effectively prevent cartilage and subchondral bone destruction in OPOA rats. The potential mechanism may be related to upregulation of PPARγ, inhibition of chondrocyte apoptosis and inflammation, and improvement of autophagy disorder. PEMF therapy thus shows promising application prospects in the treatment of postmenopausal OA.

Plain Language Summary

Osteoporotic osteoarthritis (OPOA) is a very common combination disease, that characterized by chronic pain, swollen joints and susceptibility to fractures. It is particularly common in postmenopausal women. At present, drug therapy is the main treatment method, but the adverse reactions are serious and can not stop the progression of the disease. PEMF is a safe physical therapy that has been shown to increase bone density, reduce pain, and improve joints mobility. In this study, we aimed to explore the protective effect and potential mechanism of PEMF on OPOA. We found that PEMF significantly inhibited the inflammatory response, ameliorated the damaged cartilage and subchondral bone in OPOA rats, that maybe related to the regulation of chondrocyte autophagy and apoptosis. This study provided a new vision for PEMF’ treatment on OPOA and has positive significance for the clinical promotion of PEMF.

KEYWORDS:

• Pulsed electromagnetic field
• osteoarthritis
• autophagy
• apoptosis

Acknowledgments

The authors thank AiMi Academic Services (www.aimieditor.com) for English language editing and review services.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Authors’ contributions

JL, JZ, and ZLS designed and supervised the study; XRH, LWY, XKP, LZ assisted in experimentation and performed data acquisition; JL drafted the manuscript; GHA analyzed and interpreted data; PRZ was accountable for the project management. All authors contributed to manuscript preparation and scientific discussions. All authors read and approved the final manuscript.

Additional information

Funding

This work was supported by National Natural Science Fund of China (81973917); Nature Science Foundation of Hunan (2021JJ40500); Clinical Research 4310 Program of the First Affiliated Hospital of the University of South China (20214310NHYCG07); Clinical Medical Technology Innovation Guidance Project of Hunan (2021SK51805).