ACUTE STRETCHING OF PERIPHERAL-NERVES INHIBITS RETROGRADE AXONAL-TRANSPORT

The conjugation of horseradish peroxidase with wheat germ agglutinin w as used to identify the effect on retrograde axonal transport of stret ching the rat sciatic nerve indirectly by 10% and 29% femoral lengthen ing with a unilateral external fixator. To investigate the relationshi p between retrograde axonal transport and blood flow in the stretched nerve, nerve blood flow in the sciatic nerve was measured by a hydroge n washout technique. At 11% strain (20% femoral lengthening), the numb ers of horseradish peroxidase-labelled motor neuron cells and nerve bl ood flow had decreased by 43% and 50%, respectively. Histological exam ination demonstrated ischaemic changes, bot not mechanical damage. How ever, at 6% strain (10% femoral lengthening) there were no significant abnormalities, These findings suggest that the inhibition of retrogra de axonal transport carl be induced by acute stretching of the periphe ral nerve and that circulatory disturbance is the main cause of the in hibition of retrograde axonal transport at the low strain.