Acute exposure to a moderate strength static magnetic field reduces edema formation in rats

Am J Physiol Heart Circ Physiol. 2008 Jan;294(1):H50-7. doi: 10.1152/ajpheart.00529.2007. Epub 2007 Nov 2.


External application of static magnetic fields (SMF), used specifically for the treatment of inflammatory conditions such as soft tissue injuries, has recently become popular as a complementary and/or alternative therapy with minimal investigation into efficacy or mechanism. Localized inflammation was induced via injection of inflammatory agents lambda-carrageenan (CA) or histamine into rat hindpaws, alone or in conjunction with pharmacological agents, resulting in a spatially and temporally defined inflammatory reaction. Application of a 10- or 70-mT, but not a 400-mT, SMF for 15 or 30 min immediately following histamine-induced edema resulted in a significant, 20-50% reduction in edema formation. In addition, a 2-h, 70-mT field application to CA-induced edema also resulted in significant (33-37%) edema reduction. Field application before injection or at the time of maximal edema did not influence edema formation or resolution, respectively. Together, these results suggest the existence of a therapeutic threshold of SMF strength (below 400 mT) and a temporal dependence of efficacy. Administration of pharmacological agents directed at nitric oxide signaling and L-type Ca(2+) channel dynamics in conjunction with SMF treatment and histamine-induced edema revealed that the potential mechanism of SMF action may be via modulation of vascular tone through effects on L-type Ca(2+) channels in vascular smooth muscle cells.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • 3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester / pharmacology
  • Animals
  • Arginine / metabolism
  • Calcium / metabolism
  • Calcium Channel Agonists / pharmacology
  • Calcium Channels, L-Type / drug effects
  • Calcium Channels, L-Type / metabolism
  • Carrageenan
  • Disease Models, Animal
  • Dose-Response Relationship, Radiation
  • Edema / chemically induced
  • Edema / metabolism
  • Edema / prevention & control*
  • Electromagnetic Fields*
  • Histamine
  • Inflammation / chemically induced
  • Inflammation / metabolism
  • Inflammation / prevention & control*
  • Male
  • Muscle, Smooth, Vascular / drug effects
  • Muscle, Smooth, Vascular / enzymology
  • Muscle, Smooth, Vascular / metabolism
  • Muscle, Smooth, Vascular / radiation effects*
  • Nitric Oxide / metabolism
  • Nitric Oxide Synthase / metabolism
  • Rats
  • Rats, Sprague-Dawley
  • Severity of Illness Index
  • Signal Transduction / radiation effects
  • Time Factors


  • Calcium Channel Agonists
  • Calcium Channels, L-Type
  • Nitric Oxide
  • 3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester
  • Histamine
  • Carrageenan
  • Arginine
  • Nitric Oxide Synthase
  • Calcium