Hydrogen sulfide alleviates neural degeneration probably by reducing oxidative stress and aldose reductase expression

We investigated the potential role of hydrogen sulfide (H₂S) as a novel therapy for diabetic peripheral neuropathy in diabetic rats. A single dose of streptozotocin (60 mg/kg) was applied to the rats for the diabetic rat models. Sodium bisulfide (50 μmol/kg/d) was injected intraperitoneally daily for 2 weeks as H₂S treatment. Electromyogram, haematoxylin eosin staining, transmission electron microscopy, western blotting and enzyme-linked immunosorbent assay were then performed. H₂S treatment did not affect body weights, blood glucose levels or liver function of diabetic rats, while the creatine levels of the H₂S-treated diabetic rats decreased compared with the diabetic control rats. H₂S treatment for 2 weeks did not affect the sciatic nerve conduction velocity of the diabetic rats. However, H₂S treatment relieved neurons loss and cell atrophy of dorsal root ganglion, and axon degeneration of sciatic nerve in diabetic rats. Serum super oxide dismutase (SOD) levels and SOD2 levels in the sciatic nerve of diabetic rats were lower than the non-diabetic rats but were restored after H₂S treatment. Serum and sciatic nerve homogenate malondialdehyde and aldose reductase expression were higher in diabetic rats but decreased significantly after H₂S treatment. Our study revealed that H₂S alleviates neural degeneration in diabetic rats probably by reducing oxidative stress and downregulating aldose reductase expression.