Effects of Low-Intensity Treadmill Exercise on Sciatic Nerve in Experimental Diabetic Neuropathy.

OBJECTIVE: To investigate the potential beneficial effects of low-intensity exercise on histopathological changes of sciatic nerves in streptozotocin (STZ)-induced diabetic rats. STUDY DESIGN: The rats were allotted randomly into 3 experimental groups: A (control), B (diabetic untreated), and C (diabetic treated with low-intensity exercise); each group contained 8 animals. Groups B and C received STZ. Diabetes was induced in 2 groups by a single intraperitoneal injection of STZ (40 mg/kg, freshly dissolved in 0.1 M citrate buffer, pH 4.2). Two days after STZ treatment, diabetes in 2 experimental groups was confirmed by measuring blood glucose levels. Rats with blood glucose levels >= 250 mg/dL were considered to be diabetic. Animals in the exercise group were made to run the treadmill once a day for 4 consecutive weeks. Exercise started 3 days prior to STZ administration. RESULTS: The treatment of low-intensity exercise caused a sharp decrease in the elevated serum glucose and an increase in the lowered serum insulin concentrations in STZ-induced diabetic rats. STZ induced a significant decrease in the area of insulin-immunoreactive beta cells. Low-intensity exercise treatment resulted in increased area of insulin-immunoreactive beta cells signficantly. Myelin breakdown decreased significantly after treatment with low intensity exercise. The ultrastructural features of degenerated axons also showed remarkable improvement. CONCLUSION: We believe that further preclinical research into low-intensity exercise may indicate its usefulness as a potential treatment for peripheral neuropathy in STZ-induced diabetic rats.