chronic oral pelargonidin alleviates streptozotocin-induced diabetic neuropathic hyperalgesia in rat: involvement of oxidative stress

background: diabetes mellitus in some clinical cases is accompanied with hyperalgesia. in this study, we evaluated the possible beneficial effect of chronic pelargonidin (pg) treatment on hyperalgesia in streptozotocin (stz)-diabetic neuropathic rat. methods: male wistar rats (n = 56) were divided into seven groups, i.e. control, diabetic, pg-treated control, pg (single- and multiple-dose)-treated diabetic, and sodium salicylate-treated control and diabetics. for induction of diabetes, stz was injected i.p. at a single dose of 60 mg/kg. pg was orally administered at a dose of 10 mg/kg once and/or on alternate days for 8 weeks 1 week after diabetes induction. after two months, hyperalgesia was assessed using standard formalin and hot tail immersion tests. meanwhile, markers of oxidative stress in brain were measured. one-way analysis of variance was used for statistical analysis of the data. results: diabetic rats showed a marked chemical and thermal hyperalgesia, indicating that development of diabetic neuropathy and pg treatment (especially multiple-doses) significantly ameliorated the alteration in hyperalgesia (p<0.05-0.01) in diabetic rats as compared to untreated diabetics. pg (multiple doses) also significantly decreased diabetes-induced thiobarbituric acid reactive substances formation and non-significantly reversed elevation of nitrite level and reduction of antioxidant defensive enzyme superoxide dismutase. conclusion: these results clearly suggest that pg prevents diabetic neuropathic hyperalgesia through attenuation of oxidative stress.