De Sousa Pereira A, Grande N R, Monteiro E, Castelo Branco M S, Castelo Branco N A
Abel Salazar Institute for Biomedical Sciences, University of Porto, Portugal.
Aviat Space Environ Med. 1999 Mar;70(3 Pt 2):A78-85.
Vibroacoustic disease (VAD) is a noise-induced pathology occurring in workers occupationally exposed to large pressure amplitude (> or =90 dB SPL) and low frequency (< or = 500 Hz) (LPALF) noise, over long periods of time (> or = 10 yr). Patient complaints frequently involve the respiratory tract. There have been three cases of pleural effusion of unknown etiology and with unusually long recovery times. To better understand what may be occurring we studied the effects of LPALF noise on the morphological and functional characteristics of pleural mesothelial cells of Wistar rats.
The animals were exposed to LPALF noise for periods ranging from 24-600 h. An intrapleural instillation of calcium tungstate was performed, and after sacrifice the pleural visceral and parietal leaflets were studied by scanning electron microscopy.
Acute exposure to LPALF noise caused a temporary decrease in the number of mesothelial microvilli, and prolonged exposure resulted in a definite decrease in their number as well as an impairment of their capacity to absorb particles within in the pleural space.
These results explain the pleural pathology found in human patients with VAD and confirm the deleterious effect of LPALF noise on the respiratory system.
