Subcutaneous Arteriolar Vasomotion Changes During and After ELF-EMF Exposure in Mice in Vivo

Summary Biological effects of extremely low-frequency electromagnetic fields (ELF-EMF) on microcirculation were investigated in vivo by monitoring arteriole diameters in conscious mice. Measurements of blood vessel diameter were monitored 33 min non-stop before during and after exposure with ELF-EMF and every 389 ms blood vessel diameter were calculated. Using a dorsal skinfold chamber (DSC), and following caudal vein injection of FITC-dextran 250 kDa, the microvasculature (initial arteriole diameter of 45–80 μm), was examined by intravital microscopy and video images were recorded for a total time of 33 min. Arteriole diameter was continuously measured by on-line analysis using a High-speed Digital Machine Vision System CV-2100, using an edge-gap detection algorithm. Since vessel diameters exhibit rhythmic variation expressed by vasomotion, for estimation of microcirculatory activity we used both raw data for frequency analysis of vasomotion (measured frequencies of vasomotion were in the range 0.008÷0.1 Hz) and evaluate mean blood vessel diameter for each 1 min period of time, and make a comparison between Pre, Exposure/Sham exposure and Post exposure periods, with the aim to evaluate possible changes in mean blood vessel diameter as a result of ELF-EMF action. During EMF exposure and post-exposure periods, arteriole diameters increased significantly compared with the pre-exposure period, and the changes were larger during post-exposure. In contrast to sham exposure, vasodilatation of the microvasculature was significantly greater during exposure and post-exposure to 16 Hz EMF. These findings suggest that ELF-EMF may have potential therapeutic use benefit for treating vascular disorders.