the effect of the flavonoid quercetin on pain sensation in diabetic rats

introduction: hyperalgesia is considered as one of the marked signs of subchronic diabetes mellitus in patients that could affect their lifestyle. this study was designed to investigate the anti-nociceptive effect of chronic administration of quercetin in streptozotocin (stz)-diabetic rats using formalin and hot tail immersion tests. methods: rats were divided into control, control or diabetic groups receiving sodium salicylate, untreated diabetic, and quercetin-treated control and diabetic groups. the treatment groups received i.p. administration of quercetin at a dose of 10 mg/kg for 6 weeks. finally, hyperalgesia were assessed using standard formalin and hot tail immersion tests. meanwhile, some markers of oxidative stress were also measured in brain tissue.results: quercetin or ss treatment of diabetic rats significantly reduced pain score in chronic phase of formalin test (p<0.05). regarding hot tail immersion test, diabetic rats showed a significant reduction in tail flick latency as compared to control ones (p<0.05) and quercetin treatment of diabetic rats did significantly increase this latency relative to untreated diabetics (p<0.05). quercetin treatment of diabetic rats also significantly decreased brain level of malondialdehyde (mda) (p<0.05) and nitrite (p<0.05) and slightly increased activity of superoxide dismutase (sod) relative to diabetics. discussion: taken together, chronic administration of quercetin could attenuate nociceptive score in chronic phase of formalin test in streptozotocin-diabetic rats and could also increase threshold of thermal nociception.