Pulsed electromagnetic fields mediate sensory nerve regulation for bone formation in aging models

Area of Science:

• Bone biology
• Regenerative medicine
• Neuroscience

Background:

• Osteoporosis is a growing concern in aging populations.
• Pulsed electromagnetic fields (PEMFs) show promise in enhancing bone formation.
• The precise mechanisms of PEMF action on bone health during aging are not fully understood.

Purpose of the Study:

• To investigate the role of sensory nerves and semaphorin 3A (Sema3A) in PEMF-driven bone formation in aging male mice.
• To elucidate the molecular pathways involved in PEMF's effects on mesenchymal stem cells (MSCs) and bone metabolism.

Main Methods:

• Utilized aging male mice models with intact or impaired sensory nerve function.
• Administered PEMF treatment and assessed bone formation, innervation, and adipogenesis.
• Investigated the Sema3A-neuropilin-1 (Nrp1) signaling pathway in MSCs.
• Employed genetic manipulation (nerve depletion, gene knockout) to confirm pathway involvement.

Main Results:

• PEMFs enhanced new bone formation and innervation, promoting osteogenesis and reducing adipogenesis in aging male mice.
• Sensory nerve dysfunction impaired PEMF-induced bone formation.
• PEMFs stimulated sensory nerves to secrete Sema3A, which is crucial for bone-forming effects.
• The Sema3A-Nrp1 pathway in leptin receptor-expressing MSCs mediated PEMF's anti-senescence and bone-protective effects.

Conclusions:

• PEMFs stimulate sensory nerves to produce Sema3A, which is essential for promoting osteogenesis and inhibiting adipogenesis.
• The Sema3A-Nrp1 pathway activation is critical for PEMF's therapeutic benefits in aging male bone.
• These findings highlight PEMFs' potential for treating osteoporosis in aging males.