Vascular pathology in CCI neuropathy: A quantitative temporal study

An experimental neuropathy in rats produced by tying loosely constrictive ligatures around one sciatic nerve evokes pain-related behavior that follows a reproducible time course. We have previously investigated the pathologic changes in the sciatic nerve in this model, and a striking feature was protrusion and proliferation of endoneurial endothelial cells. In the present study, we quantified these changes at time points from 1 day to 12 weeks after surgery. One day after surgery, vessels were distended, shown by an increase of the slope of a graph in which the vessel areas were plotted on the x axis and luminal areas on the y axis. From Day 7, the slope was reduced; i.e., vessel walls had thickened and lumina were smaller. By Day 14, narrowing of lumina was observed in the contralateral (control) nerve also. We suggest that endothelial cell proliferation, known to be induced by cytokines produced by macrophages, indicates increased activity and pathogenic significance of these cytokines in the CCI model. (C) 1996 Academic Press, Inc.