Neuroscience

Prolonged occupational exposure to hand-held vibrating tools leads to pain and reductions in tactile sensitivity, grip strength and manual dexterity. The goal of the current study was to use a rat-tail vibration model to determine how vibration frequency influences factors related to nerve injury and dysfunction. Rats were exposed to restraint, or restraint plus tail vibration at 62.5\u202fHz or 250\u202fHz. Nerve function was assessed using the current perception threshold (CPT) test. Exposure to vibration at 62.5 and 250\u202fHz, resulted in a reduction in the CPT at 2000 and 250-Hz electrical stimulation (i.e. increased A\u3b2 and A\u3b4, nerve fiber sensitivity). Vibration exposure at 250\u202fHz also resulted in an increased sensitivity of C-fibers to electrical stimulation and thermal nociception. These changes in nerve fiber sensitivity were associated with increased expression of interleukin (IL)-1\u3b2 and tumor necrosis factor (TNF)-\u3b1 in ventral tail nerves, and increases in circulating concentrations of IL-1 \u3b2 in rats exposed to 250-Hz vibration. There was an increase in glutathione, but no changes in other measures of oxidative activity in the peripheral nerve. However, measures of oxidative stress were increased in the dorsal root ganglia (DRG). These changes in pro-inflammatory factors and markers of oxidative stress in the peripheral nerve and DRG were associated with inflammation, and reductions in myelin basic protein and post-synaptic density protein (PSD)-95 gene expression, suggesting that vibration-induced changes in sensory function may be the result of changes at the exposed nerve, the DRG and/or the spinal cord.CC999999/Intramural CDC HHS/United States2019-11-01T00:00:00Z30553794PMC6545897691