Assessment of 3-nitropropionic acid-evoked peripheral neuropathy in rats: neuroprotective effects of acetyl-l-carnitine and resveratrol

Oxidative stress and secondary excitotoxicity, due to cellular energy deficit, are major factors playing roles in 3-nitropropionic acid (3-NPA) induced mitochondrial dysfunction. Acute or chronic exposure to 3-NPA also leads to neuronal degeneration in different brain regions. The present study quantitatively assessed peripheral neuropathy induced by chronic exposure to 3-NPA in rats. The neuroprotective abilities of two antioxidants, acetyl-l-carnitine and resveratrol, were investigated as well. Rats were exposed for up to four weeks to 3-NPA alone or 3-NPA combined with acetyl-l-carnitine or resveratrol, administered peripherally. The experimental outcome was evaluated by neurophysiological, histological, and morphometric analyses. Rats exposed to 3-NPA developed hind limb paresis. Furthermore, a significant decrease in motor nerve conduction velocity (MCV) was detected in tail nerves and axonal degeneration in sciatic nerves (p<0.05). Treatment with resveratrol prevented the functional effects of 3-NPA exposure, whereas treatment with acetyl-l-carnitine, preventing paresis, was not effective to MCV and morphological changes. These data suggest that resveratrol is a good candidate for treatment of metabolic neuropathy. The experimental outcome of this study shows that chronic treatment with 3-NPA in rats is relevant in development of an experimental model of toxic neuropathy.