Effect of exercise and vitamin E on pain threshold in type I diabetic rats

Introduction: Oxidative stress is an important factor in the induction of diabetes complications especially peripheral neuropathy and hyperalgesia, and it has been proven that regular aerobic exercise and vitamin E have antioxidant effects. Therefore, this study was designed to examine effects of regular aerobic exercise and vitamin E on thermal pain threshold in streptozocin-induced diabetic rats. Methods: Male Wistar rats (250±10 g) were made diabetic by streptozotocin (60 mg/kg, subcutaneously). One week after diabetes induction, animals were subjected to aerobic exercise and vitamin E treatment for 6 weeks. Aerobic exercise consisted of running on treadmill, and vitamin E (7 g/kg) was added into daily food. Forty eight hours after the end of 3rd and 6th weeks of exercise protocol, we used tail-flick to assess the effects of training and vitamin E on thermal pain threshold. Results: 1) A significant decrease in thermal pain threshold was seen in diabetic rats. 2) Diabetes-induced hyperalgesia decreased significantly by regular aerobic exercise and vitamin E. 3) The effect of simultaneous regular aerobic exercise and vitamin E on thermal pain threshold was significantly more than the effect of each one alone. Conclusion: Regular exercise and vitamin E administration at the time of diabetes induction may be able to restore thermal hyperalgesia. Therefore, they can be used for the treatment and/or management of painful conditions.