Bradykinin B₁ antagonism inhibits oxidative stress and restores Na+K+ ATPase activity in diabetic rat peripheral nervous system.

Diabetic peripheral neuropathy is one the most common complications of diabetes mellitus and frequently results in clinically significant morbidities such as pain, foot ulcers and amputations. The diabetic condition progresses from early functional changes to late, poorly reversible structural changes. The chronic hyperglycemia measured alongside diabetes development is associated with significant damage and failure of various organs. In the present study diabetes was induced in male Wistar rats by a single dose of streptozotocin (STZ) and the association between the BKB1-R and the oxidative stress and Na+-K+ ATPase activity in nervous tissues was analysed. The results showed that the resulting hyperglycemia induced a reduction of the neuronal electrical function integrity and increased oxidative stress in the sciatic nerve homogenates of 30 days diabetic rats. Malondialdehyde (MDA) used as a marker of oxidative stress was elevated whereas Biological Antioxidant Potential (BAP), glutathion (GSH) levels and superoxide dismutase (SOD) activity were decreased. Treatment of the rats 3 days before the end of the 4 week period with the BKB1 antagonist R-954 restored the neuronal activity and significantly attenuated the oxidative stress as shown by the level of the various markers returning close to levels found in control rats. Our results suggest that the BKB1-R subtype is overexpressed in sciatic nerve during the STZ-induced diabetes development as evidenced by inhibitory effects of the BKB1-R antagonist R-954. The beneficial role of BKB1-R antagonist R-954 for the treatment of diabetic neuropathy is also suggested.