Effects of riboflavin on hyperalgesia and serum glutamine-to-glutamate ratio in rats with painful diabetic neuropathy

Previous studies have explored the antinociceptive effects of riboflavin (vitamin B2) across various experimental models. However, there remains a gap in the literature regarding its potential to alleviate neuropathic pain in diabetes. This study aims to investigate the effects of riboflavin on hyperalgesia and serum glutamine-to-glutamate ratio in rats with painful diabetic neuropathy. In fasted rats, a model of painful diabetic neuropathy was induced through intraperitoneal injection of streptozotocin. In the fifth week post-injection, diabetic rats experiencing neuropathic pain were administered daily doses of riboflavin (25 or 50 mg), dissolved in their drinking water, for a duration of two weeks. Results demonstrate that riboflavin significantly reduced mechanical and cold-induced hyperalgesia in diabetic rats compared to controls. Formalin-induced hyperalgesia was alleviated by riboflavin in the second phase. Additionally, riboflavin supplementation increased the serum glutamine-to-glutamate ratio in these animals. These findings highlight the therapeutic potential of riboflavin in managing neuropathic pain associated with diabetes.