Abstract
Experiments were performed to evaluate the influence of frequencies in long-term local vibration exposure on the occurrence of intimal thickening of the peripheral arteries. The hind legs of rats were exposed to local vibration (60Hz, 5G and 480Hz, 5G) four hours a day for 90 days. In three of five rats exposed to 60Hz, disruption of the internal elastic lamina was observed in the small arteries at the exposed site. The disruption was followed by focal cell proliferation with regenerative formation of collagen and elastic fibers. The fibrocellular thickening of the intima was further augmented and a complete stenosis of the lumen of the small artery was observed. In all three of the rats exposed to 480Hz, histological alterations of small arteries were also recognized at the exposed site. These alterations, however, were only disruptions of the internal elastic lamina followed by focal cell proliferation.
