Sciatic nerve stimulation increases the degree of histopathological damage in lumbosacral segments after short lasting spinal cord ischemia in rabbit

To characterize the influence of primary afferent activation on the development of histopathological changes in the spinal cord after reversible ischemia, the left sciatic nerve was stimulated at the intensity of myelinated fibers before, during and for 1 h after 10 min of abdominal aortic ligation in halothane anesthetized rabbits. In control animals, only 10 min of spinal cord ischemia or sciatic nerve stimulation was employed. One hour after reperfusion all animals were perfusion fixed with 4% paraformaldehyde. Histopathological analysis using the suppressive Nauta method revealed significantly higher number of argyrophilic neurons in dorsal horns and in the intermediate zone in animals in which spinal cord ischemia was combined with sciatic nerve stimulation in comparison with the animals with spinal cord ischemia, but without stimulation. These histopathological changes corresponded with signs of irreversible damage analyzed on the ultrastructural level. Stimulation of sciatic nerve, but without ischemia did not evoke any detectable neuronal changes. The data from the present study suggest that increased activity of spinal cord neurons evoked by peripheral nerve stimulation can be an important factor in determining the extent of irreversible damage after short lasting ischemia.