The effect of static magnetic fields on the hemodynamics of the microcirculation has not been sufficiently studied invivo. We used a transparent chamber which is surgically constructed on the back of a rat. This technique provides an excellent means of observing and quantifying the microvessels of the skin, to quantitatively assess the response of the microcirculation to static magnetic fields up to 8 T.Using an intravital videomicroscope, we observed the changes in diameter of the microvessels whose diameters are 30μm to 80μm under control conditions after magnetic exposure to a horizontal type of superconducting magnet with a bore 100 mm in diameter and 700 mm long. We also recorded the blood pressure during exposure. Nine animals (n=14) exhibited significant vasodilatation after exposure.The magetic fields also decreased the mean blood pressure (n=6). This study provided experimental evidence that static magnetic fields have some vasodilating effect on the microvessels in vivo.
