Role of Cell Oxidant Status and Redox State in Controlling Cell Proliferation and Apoptosis in Two Models of Wallerian Degeneration of Rat Sciatic Nerve

After peripheral nerve lesion, the role of reactive oxygen species (ROS) has not been clarified during Wallerian degeneration. The present study examined the participation of oxidant stress after rat sciatic nerve injury induced by two experimental models (crush and transection). Here, biochemical parameters indicative of oxidant stress, nitric oxide (NO) metabolism, cell proliferation, apoptosis, and bioenergetics were determined in injured and contralateral sciatic nerves and caudofemoralis muscle. After crushing, we found two peaks of increased lipid peroxidation (LP) by-products and carbonylation of proteins in crushed nerves. In transected nerves, increases in LP showed similar patterns in both proximal and distal nerve. In both models, NO production was decreased and accompanied by an early increase in cell proliferation. Moreover, caspase-3 activity increased later only in crushed nerves. NAD availability and mitochondrial cytochrome oxidase activity were increased in transected but not in crushed nerves. The contralateral nerves also had changes in these parameters, but in a differential manner depending on the type of nerve lesion. In conclusion, present data suggest that changes in the patterns of LP may play a regulatory role in cell damage and death, somehow exerting a control in the progression of Wallerian degeneration.