Impaired glucose regulation (IGR) constitutes a spectrum of impaired glucose and metabolic regulation that can result in neuropathy. Several different pathways of injury in the diabetic peripheral nervous system that include metabolic dysregulation induced by metabolic syndrome induce oxidative stress, failure of nitric oxide regulation, and dysfunction of certain key signaling pathways. Oxidative stress can directly injure both dorsal route ganglion neurons and axons. Modulation of the nitric oxide system may have detrimental effects on endothelial function and neuronal survival. Reactive oxidative species can alter mitochondrial function, protein and DNA structure, interfere with signaling pathways, and deplete antioxidant defenses. Advanced glycelation end (AGE) products and formation of ROS are activated by and in turn regulate key signal transduction pathways.