Acetyl-L-carnitine corrects the altered peripheral nerve function of experimental diabetes

Area of Science:

• Neuroscience
• Biochemistry
• Pharmacology

Background:

• Diabetic neuropathy is characterized by diminished nerve conduction velocity (NCV).
• The polyol pathway, involving sorbitol and myo-inositol, is implicated in diabetic nerve dysfunction.
• Acetyl-L-carnitine (ALC) aids nerve repair, while aldose reductase inhibitors like sorbinil may normalize NCV in diabetes.

Purpose of the Study:

• To evaluate the effect of ALC on NCV in rats with streptozotocin (STZ)-induced diabetes.
• To compare ALC's efficacy with sorbinil, a known aldose reductase inhibitor and positive control.
• To investigate the impact of ALC and sorbinil on nerve polyol pathway metabolites and lipid peroxidation.

Main Methods:

• Induction of diabetes in rats using streptozotocin (STZ).
• Treatment of STZ-diabetic rats with ALC (50 mg/kg/d) or sorbinil.
• Measurement of sciatic nerve conduction velocity (NCV).
• Assay of sciatic nerve sorbitol, myo-inositol, and malondialdehyde (MDA) content.

Main Results:

• Both ALC and sorbinil treatments normalized the reduced NCV in STZ-diabetic rats.
• Sorbinil normalized sciatic nerve sorbitol and myo-inositol levels.
• ALC normalized myo-inositol but not sorbitol levels, yet both treatments reduced elevated MDA, indicating decreased lipid peroxidation.
• Despite similar functional improvements, ALC and sorbinil exhibited distinct effects on the polyol pathway.

Conclusions:

• ALC and sorbinil effectively improve nerve conduction velocity in experimental diabetes.
• Both compounds mitigate lipid peroxidation in diabetic nerves.
• ALC and sorbinil exert their beneficial effects through different mechanisms concerning the polyol pathway.