Effects of Beraprost Sodium, a Prostacyclin Analogue, on Diabetic Neuropathy in Streptozotocin-Induced Diabetic Rats

Abstract

The effects of beraprost sodium (BPS), a stable prostacyclin analogue, on motor nerve conduction velocity and nerve blood flow of the sciatic nerve were investigated in streptozotocin-induced diabetic rats, and they were compared with the effects of epalrestat (aldose reductase inhibitor). Treatment with BPS for 4 weeks significantly inhibited the decrease in motor nerve conduction velocity and nerve blood flow dose-dependently, but epalrestat had no effect on nerve blood flow. Morphological changes of the myelinated fibers of the sciatic nerve were observed macroscopically. The mean axonal area and the mean circularity index of diabetic control rats were significantly less than that of normal rats, while after 6 weeks of BPS treatment, these decreases of the axonal area and the circularity index were inhibited. The enlargement of the mean lumen area of microvessels in the diabetic rats was significantly inhibited after 6 weeks of BPS treatment. Additionally, augmentation of the washed platelet aggregation in diabetic rats was significantly normalized by BPS. It was suggested that BPS is effective on diabetic neuropathy via amelioration of the decrease of blood supply to the structure. The effects of BPS on platelets might also contribute to the improvement of neuronal circulatory deficiency.