European Journal of Anatomy

Official Journal of The Spanish Society of Anatomy
Cover Volume 6 - Number 1
Eur J Anat, 6 (1): 17-21 (2002)

Vascular lesions and vibroacoustic disease

Dos Santos J.M., Grande N.R., Castelo Branco N.A., Zagalo C., Oliveira P.

Insto. Sup. de Cie. da Saude -Sul, 2829-511 Monte Caparica, Portugal

ABSTRACT Low frequency noise (LFN) (? 90 dB SPL, ? 500 Hz) is an agent of disease that regularly goes unchecked during standard noise assessment procedures. Vibroacoustic disease (VAD) is an extra-aural noise-induced systemic pathology, caused by long-term exposure to LFN and characterised by a proliferation of extra-cellular matrices. The present study attempts to elucidate the behaviour of medium-and large-calibre blood vessels in the presence of insult due to noise and vibration. Thirty-five adult Wistar rats were studied. The animals were divided into 3 groups. One group of 20 rats was exposed to large pressure amplitude and low frequency (LPALF) noise in an occupationally simulated schedule: 8 h/day, 5 days/week, and weekends in silence, for 968 to 1984 (median 1576 h) cumulative hours of noise exposure. Another group of 5 rats was exposed to 24 h of continuous noise. The last group of 10 rats (control) was kept under identical conditions but in a silent environment. Overall noise levels were recorded above 109 dB, the A-weighted levels being around 98 dB (A). The rats were sacrificed and fragments of aorta, inferior vena cava and femoral artery and vein from both hindlimbs, were collected; these were prepared for histological examination. With long-term exposure, the aorta and the femoral artery showed a focal thickening of the intima, disruption of the internal elastic lamina and a proliferation of smooth muscle cells in the intima in 70% of the cases. With acute exposure, the lesions appeared in 60% of the cases observed. Most of the lesions involved the appearance of clefts in the media, pulling the cells and the elastic membranes apart. The media thickness-to-inner caliber ratio of the femoral artery was increased (p<0.05). Our results point to a remodelling of the vessels that can be attributed to vibration and flow disturbances. The observed remodelling was not observed in small vessels.

Keywords: animal experiment, animal model, animal tissue, aorta, artery diameter, artery intima proliferation, artery media, article, cell proliferation, controlled study, environmental exposure, extracellular matrix, femoral artery, hindlimb, histology, industrial noise, inferior cava vein, long term exposure, low frequency noise, noise injury, nonhuman, occupational exposure, pressure, rat, rat strain, simulation, smooth muscle fiber, thickness, vein, vibration, vibroacoustic disease

European Journal of anatomy
ISSN 2340-311X (Online)