Acute effects of whole-body exposure to static magnetic fields and 50-Hz electromagnetic fields on muscle microcirculation in anesthetized mice.
Acute microhemodynamic effects of static and alternating magnetic fields at a threshold level were investigated on modulating the muscle capillary mirocirculation in pentobarbital-anesthetized mice. The skin in a tibialis anterior was circularly removed with 1.5 mm diameter for intravital-microscopic recording of the capillary blood velocity in the tibialis anterior muscle. Fluorescein isothiocyanate (FITC)-labeled dextran (MW 150 kDa) was used for an in vivo fluorescent plasma marker of the muscle capillaries. Following a bolus injection of FITC-dextran solution into the caudal vein, the peak blood velocity in the muscle capillaries was measured prior to, during, and following exposure to static magnetic fields (SMF) or 50-Hz electromagnetic fields (EMF) using a fluorescence epi-illumination system. The whole body of experimental animals, placed on the observing stage of a fluorescence microscope, was exposed to SMF (0.3, 1 and 10 mT) or 50-Hz EMF (0.3 and 1 mT) for 10 min using a specially devised electromagnet. For sham exposure, the electromagnet was not energized. During exposure and post-exposure to SMF of 10 mT, the peak blood velocity significantly increased as compared to sham exposure. After the withdrawal of SMF and 50-Hz EMF of 1 mT, significant similar effects on the blood velocity were present or enhanced. These findings suggest that field intensity of 1 mT might be considered as a threshold level for enhancing muscle microcirculation under pentobarbital-induced hypnosis.
Xu
S
S
Department of Physiological Hygiene, National Institute of Public Health, Tokyo, Japan.
Okano
H
H
Ohkubo
C
C
D000818:Animals; D001783:Blood Flow Velocity / Q000528:radiation effects; D003911:Dextrans / Q000008:administration & dosage; D004574:Electromagnetic Fields; D004867:Equipment Design; D016650:Fluorescein-5-isothiocyanate / Q000008:administration & dosage / Q000031:analogs & derivatives; D005456:Fluorescent Dyes; D008280:Magnetics; D051379:Mice; D008833:Microcirculation / Q000528:radiation effects; D008856:Microscopy, Fluorescence; D018482:Muscle, Skeletal / Q000098:blood supply*; D010424:Pentobarbital / Q000494:pharmacology; D012039:Regional Blood Flow / Q000528:radiation effects
D003911:Dextrans; D005456:Fluorescent Dyes; C015219:fluorescein isothiocyanate dextran; D016650:Fluorescein-5-isothiocyanate; D010424:Pentobarbital