CHRONIC CONSTRICTION MODEL OF RAT SCIATIC-NERVE - NERVE BLOOD-FLOW, MORPHOLOGIC AND BIOCHEMICAL-ALTERATIONS

We evaluated the nerve blood flow (NBF), light and electron microscopy , and adrenergic innervation of rat sciatic nerve at 2-45 days after t he application of four loose ligatures. Ischemia developed at the lesi on edge, creating an endoneurial dam. Calcitonin gene-related peptide, norepinephrine and NBF were increased within the lesion. Morphologic alterations consisted of early endoneurial edema, followed by myelinat ed fiber degeneration, with relative sparing of small myelinated and u nmyelinated nerve fibers, and leukocyte adhesion to microvessels. Axon al degeneration predominated over demyelination. At 45 days, profuse r egeneration of small myelinated fibers was seen. The mechanism of lesi onal sensitization is discussed.