Vibration causes ischemia‐reperfusion injury in the rat‐tail artery

Abstract

Hand-arm vibration syndrome is a vasospastic disease affecting workers using hand held powered-tools. In a rat-tail vibration model, 4 hr of 60 Hz vibration caused free radical production (nitration) in the ventral artery. To test if ischemia-reperfusion causes free radical production, tails of male Sprague-Dawley rats were vibrated 4 hr at 60 Hz, 49 m/s2acceleration. Blood perfusion to the tail skin was monitored with laser Doppler after 5 min, 1, 2 and 4 hr of vibration. Perfusion was significantly reduced to 62% by 5 min, 94% at 2 and 4 hr, and significantly increased to 122% at 3 hr of exposure. In other rats, tails were vibrated 5 min, 1, 2 or 4 hr at 60 Hz, 49 m/s2, and ventral arteries were processed for light microscopy. Compared to control, 100% of 5 min, 50% of 1 hr, 75% of 2 hr and 57% of 4 hr vibrated animals had smaller arterial lumens with morphological signs of endothelial and smooth muscle cell vacuolation damage. The vibration-induced transient reduction in skin blood flow, the morphological signs of vasoconstriction and the temporal pattern of vasoconstriction and dilation indicate that vibration immediately induces vasoconstriction which is followed by cycles of relaxation and constriction. This temporal pattern is consistent with ischemia reperfusion generating free radicals-induced nitration in the artery. Support: Medical College of Wisconsin, NIOSH grant R01 OH003493