Vibration causes acute vascular injury in a two-step process: vasoconstriction and vacuole disruption.
Govindaraju SR; Bain JL; Eddinger TJ; Riley DA
Anat Rec 2008 Aug; 291(8):999-1006
Hand-arm vibration syndrome is a vasospastic and neurodegenerative occupational disease. In the current study, the mechanism of vibration-induced vascular smooth muscle cell (SMC) injury was examined in a rat-tail vibration model. Tails of male Sprague Dawley rats were vibrated continuously for 4 hr at 60 Hz, 49 m/s(2) with or without general anesthesia. Ventral tail arteries were aldehyde fixed and embedded in epoxy resin to enable morphological analysis. Vibration without anesthesia caused vasoconstriction and vacuoles in the SMC. Anesthetizing rats during vibration prevented vasoconstriction and vacuole formation. Exposing tail arteries in situ to 1 mM norepinephrine (NE) for 15 min induced the greatest vasoconstriction and vacuolation. NE induced vacuoles were twice as large as those formed during vibration. When vibrated 4 hr under anesthesia after pretreatment with NE for 15 min, the SMC lacked vacuoles and exhibited a longitudinal banding pattern of dark and light staining. The extracellular matrix was filled with particulates, which were confirmed by electron microscopy to be cellular debris. The present findings demonstrate that vibration-induced vasoconstriction (SMC contraction) requires functioning central nervous system reflexes, and the physical stress of vibration damages the contracted SMC by dislodging and fragmenting SMC vacuoles.
Vibration; Vibration-disease; Vibration-control; Vibration-effects; Vibration-exposure; Neurovascular-disorders; Animal-studies; Animals; Laboratory-animals; Biological-effects; Biological-monitoring; Musculoskeletal-system-disorders; Musculoskeletal-system;
Author Keywords: hand-arm vibration; rat-tail artery; smooth muscle cells; norepinephrine
Danny A. Riley, Department of Cell Biology, Neurobiology & Anatomy, 8701 Watertown Plank Road, Medical College of Wisconsin, Milwaukee, WI 53226
Manufacturing; Wholesale and Retail Trade
Medical College of Wisconsin, Milwaukee, Wisconsin