RESUMO
This study was designed to investigate the antinociceptive effect of chronic administration of the flavonoid hesperetin in streptozotocin-diabetic rats using formalin and hot tail immersion tests. Rats were divided into 5 control groups, hesperetin-treated control, diabetic, sodium salicylate [SS] -treated diabetic, and hesperetin-and glibenclamide-treated diabetic groups. Hesperetin [10 mg/kg] was administered i. p. one other day 1 week after diabetes induction for 6 weeks. Finally, thermal pain tolerance and nociception were evaluated using hot water tail immersion and formalin tests respectively. Diabetic rats exhibited a higher score of pain at both phases of the formalin test [P<0.05] and hesperetin-treated diabetic rats exhibited a lower nociceptive score at both phases of the test [P<0.05]. Regarding thermal pain tolerance, diabetes significantly reduced tail immersion latency [P<0.01] and hesperetin treatment did produce a significant change in this respect [P<0.05]. Chronic treatment with hesperetin for 6 weeks does mildly increase thermal pain tolerance and reduces chemical nociception in an experimental model of diabetes mellitus and this may be considered as an auxiliary treatment for diabetic hyperalgesia