Assessment of spinal cord trauma using evoked potentials in a rat model of decompression sickness

A rapid quantitative technique for assessing spinal cord trauma in a rat model of decompression sickness is described. Evoked potentials are measured from the lower limbs of rats before and after dives with compressed air in a hyperbaric chamber. Under chloral hydrate anesthesia, the sciatic nerve is stimulated at the sciatic notch with needle electrodes and platinum/iridium electrodes are used to record the action potentials from the plantar muscles. Analysis showed that the sensory reflex response was markedly depressed in the rats soon after diving and did not recover for up to 5 days. The motor response was similarly affected although to a lesser degree. The latency of the reflex response also became prolonged after 3 days. The significant and complex pattern of neurological dysfunction shown by this electrophysiologic technique validates the use of the rat model for the study of spinal cord decompression sickness. This technique should aid studies aimed at testing new therapies for this disease.