A lipoic acid-gamma linolenic acid conjugate is effective against multiple indices of experimental diabetic neuropathy

Abstract

Untreatedstreptozotocin-diabetic (7 weeks duration) rats showed reductions (all p < 0.01; percentages in brackets) in motor and sensory nerve conduction velocity (MNCV; 14%, SNCV; 17%) and in sciatic nerve contents of nerve growth factor (NGF; 57%), substance P (SP; 53 %) and neuropeptide Y (NPY; 39 %). Treatment with a γ-linolenic acid-α-lipoic acid conjugate (GLA-LA; 35 mg · day-51 · rat-1) attenuated (p <0.05) these reductions to MNCV (8%), SNCV (5%), NGF (19%), SP (230), NPY (20%), such that the values in GLA-LA-treated diabetic rats did not differ significantly from those of control non-diabetic animals. Treatment with alphalipoic acid alone at 100 mg/kg i.p. was without effect on these variables except for NGF (33 % reduction, p < 0.05) and treatment with the antioxidant, butylated hydroxytoluene (1.5% dietary supplement) did not affect any deficits. These data show that GLA-LA is effective in improving both electrophysiological and neurochemical correlates of experimental diabetic neuropathy.