Static magnetic fields affect capillary flow of red blood cells in striated skin muscle.
Blood flowing in microvessels is one possible site of action of static magnetic fields (SMFs). We evaluated SMF effects on capillary flow of red blood cells (RBCs) in unanesthetized hamsters, using a skinfold chamber technique for intravital fluorescence microscopy. By this approach, capillary RBC velocities (v(RBC)), capillary diameters (D), arteriolar diameters (D(art)), and functional vessel densities (FVD) were measured in striated skin muscle at different magnetic flux densities. Exposure above a threshold level of about 500 mT resulted in a significant (P < 0.001) reduction of v(RBC) in capillaries as compared to the baseline value. At the maximum field strength of 587 mT, v(RBC) was reduced by more than 40%. Flow reduction was reversible when the field strength was decreased below the threshold level. In contrast, mean values determined at different exposure levels for the parameters D, D(art), and FVD did not vary by more than 5%. Blood flow through capillary networks is affected by strong SMFs directed perpendicular to the vessels. Since the influence of SMFs on blood flow in microvessels directed parallel to the field as well as on collateral blood supply could not be studied, our findings should be carefully interpreted with respect to the setting of safety guidelines.
Brix
Gunnar
G
Federal Office for Radiation Protection, Department of Medical Radiation Hygiene and Dosimetry, Neuherberg, Germany. gbrix@bfs.de
Strieth
Sebastian
S
Strelczyk
Donata
D
Dellian
Marc
M
Griebel
Jürgen
J
Eichhorn
Martin E
ME
Andrā
Wilfried
W
Bellemann
Matthias E
ME
D000818:Animals; D001160:Arterioles / Q000502:physiology / Q000528:radiation effects; D002196:Capillaries / Q000502:physiology / Q000528:radiation effects; D006224:Cricetinae; D004574:Electromagnetic Fields; D004912:Erythrocytes; D008647:Mesocricetus; D008833:Microcirculation / Q000502:physiology / Q000528:radiation effects; D008856:Microscopy, Fluorescence / Q000295:instrumentation / Q000379:methods; D008955:Models, Cardiovascular; D054792:Muscle, Striated / Q000098:blood supply*; D051381:Rats; D012039:Regional Blood Flow / Q000502:physiology* / Q000528:radiation effects*; D012867:Skin / Q000098:blood supply*