Authors:
Cassandra E. Morris and Thomas C. Skalak
Summary:
External application of static magnetic fields, utilized 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 -carrageenan (CA) or histamine into rat hindpaws, alone or in conjunction with pharmacologic agents, resulting in a spatially and temporally defined inflammatory reaction. Application of a 10mT or 70mT, but not a 400mT SMF for 15 or 30 minutes immediately following histamine-induced edema resulted in a significant, 20-50% reduction in edema formation. Additionally, a 2 hour, 70mT 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 400mT) and a temporal dependence of efficacy. Administration of pharmacologic agents directed at NO signaling and L-type Ca2+ 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 Ca2+ channels in vascular smooth muscle cells.
Source:
American Journal of Physiology: Heart and Circulatory Physiology, November 2, 2007