Moreover, lipoic acid has reported beneficial effects in the treatment of diabetes complications.[34] Additionally, methylcobalamin could promote myelinogenesis and axon regeneration through nucleic acid and protein synthesis, repairing peripheral nerve injury.[35,36] Our study showed that the serum apelin level was closely associated with DPN and its expression was decreased after lipoic acid and methylcobalamin, thus preventing the progression of neuropathy. This evidence concerns the gene APLN and neuropathy.