Intraspinal degenerative atrophy caused by sciatic nerve lesions prevented by acetyl-L-carnitine

Peripheral nerve lesions cause retrograde changes in the spinal cord, involving initially the descending serotoninergic pathways and later the substance P sensory input and methionine-enkephalin interneurons. Within 48 h after sciatic nerve resection there is a significant increase of 5-hydroxyindoleacetic acid in the lumbar spinal cord with no changes of serotonin metabolism in the cell body areas. The immunocytochemical analysis of the spinal cord shows that 20 days after nerve lesion there is a loss of substance P-positive boutons in the laminae I and II of the dorsal horn in the lumbar segment. Such a morphological change is correlated by radioimmunoassay for substance P and methionine-enkephalin, that reveals a significant loss of both peptides. Treatment with acetyl-L-carnitine prevents the early 5-hydroxyindoleacetic acid increase and the reduction of peptide content observed 20 days after lesioning the sciatic nerve. These data suggest that treatment with acetyl-L-carnitine exerts a neuroprotective activity preventing the retrograde changes triggered by peripheral nerve lesions.