Lymphatic lesions and vibroacoustic disease

Introduction. Long-term (years) exposure to low frequency noise (LFN) (≤ 500 Hz, including infrasound) can lead to the development of vibroacoustic disease (VAD). In animal models, oedema is an immediate and sustained response to LFN exposure. Goal. To investigate possible a) alterations of lymphatic morphology, and b) lesions of the lymphatic network in LFN-exposed rodents. Methods. Twenty rats were exposed to LFN (8 hrs/day, 5 day/week, weekends in silence), and 10 rats were kept in equal conditions but in silence. After a cumulative exposure 1576 hours, animals were sacrificed, and fragments of femoral artery and vein and femoral lymphatics from both hindlimbs were collected for histological examination. Results. Lymphatic walls are greatly thickened with numerous small lymphatics exhibiting severe lumen dilation. Disruption of the valvular apparatus is also identifiable. Discussion. Changes in lymphatic morphology and disruption of lymphatic valvular apparatus in LFN-exposed rodents are sequelae of the organism's LFN-induced response.