[Studies of electrophysiological and morphological changes in the rabbit sciatic nerve under various types of stretch...

Electrophysiological and morphological changes of rabbit sciatic nerve during high-speed stretch, stepwise stretch and low-speed stretch were investigated. In the high-speed nerve stretch of ten millimeters, rapid decrease in amplitude with temporal dispersion and delay of peak latency were noted at an early period of the conditioning, revealing a tendency to recovery of the function. In the nerve under step-wise stretch, gradual progression of dysfunction was noticed along with a slight increase of the stretch with no obvious recovery signs, and the limit of the functional recovery was estimated at a 60% loss of peak amplitude of the action potentials. Histologic and electron microscopic changes of the nerves with functional loss showed swelling with separation of the myelin sheath and narrowing of the axons mainly located in the paracentral area of the nerve with intact nerve sheaths.