Mechanisms of Action of Low-Frequency Pulsed Magnetic Fields in Peripheral Nerve Regeneration

Peripheral nerve regeneration remains one of the most difficult clinical problems in neuropathy management, and no currently approved treatment reliably restores nerve structure once damage has occurred. Low-frequency pulsed magnetic fields (LFPMFs) have attracted interest primarily as an analgesic modality, culminating in FDA clearance of a magnetic peripheral nerve stimulation (mPNS) device for painful diabetic neuropathy. However, accumulating preclinical data suggest that LFPMFs may act on the biological determinants of nerve repair, not merely on pain transmission. This review organizes those mechanisms chronologically. Early effects center on the endoneurial microvasculature: LFPMF exposure promotes release of FGF-2 and VEGF from endothelial cells, drives arteriolar dilation, and stimulates capillary neogenesis, restoring oxygen delivery to ischemic nerve segments. These vascular changes are especially relevant in diabetic neuropathy and peripheral vascular disease, where endoneurial ischemia drives progressive fiber loss. Later effects involve Schwann cell proliferation, downregulation of neuroinflammatory cytokines, upregulation of BDNF, NGF, and GDNF, and acceleration of axonal sprouting through calcium-dependent intracellular signaling. Notably, the Brown et al. trial of high-intensity mPNS reported a 53% reduction in numbness—a finding that cannot be explained by analgesia alone and raises the possibility that clinical-grade devices may drive structural regeneration. Whether the regenerative mechanisms identified with lower-power devices translate to, or are amplified by, high-intensity mPNS remains an open and important question.