Pramipexole protects against diabetic neuropathy: Effect on oxidative stress, TLR4/IRAK-1/TRAF-6/NF-κB and downstream inflammatory mediators

Background: Diabetic neuropathy (DN) is a serious microvascular complication and a major cause of morbidity and mortality in diabetes mellitus. It is characterized by neurodegeneration of terminal sensory nerve fibers with subsequent pain, loss of sensation, and paresthesia, thus compromising the quality of life of diabetic patients. It is considered the leading cause of non-traumatic amputations worldwide, reflecting the insufficiency of current therapies. Pramipexole (PPX) is a dopamine receptor agonist used for the treatment of Parkinson's disease. The current study aims to investigate the potential neuroprotective effect of PPX in an experimental model of DN. Methods: Sprague Dawley rats were randomly assigned into five groups: normal control, Normal + PPX (1 mg/kg) group, STZ control, STZ + PPX (0.25 and 1 mg/kg/day for eight weeks). The neuroprotective effect of PPX in rats was evaluated in terms of sciatic nerve histological alterations, oxidative stress, and protein expression of TLR4/ MyD88/IRAK-1/TRAF-6/NF-kappa B axis and downstream inflammatory mediators. Results: PPX administration ameliorated histopathological signs of neuronal inflammation and apoptosis. Additionally, PPX attenuated STZ-induced sciatic nerve oxidative stress and downregulated neural tissue expression of TLR4, MyD88, IRAK-1, TRAF-6, NF-kappa B and downstream mediators (TNF-alpha, IL-1 beta and ICAM-1). Conclusion: Collectively, the current study sheds light on PPX as a potential protective medication to alleviate neuropathy progression in diabetic patients. PPX neuroprotective effect can be attributed to modulating TLR4/ MyD88/IRAK-1/TRAF-6/ NF-kappa B axis signaling in nerve tissues with subsequent attenuation of oxidative stress and inflammation.