The investigation of effects quercetin treatment on cyclooxygenase-2 and inducible nitric oxide synthase levels at experimental diabetic rat

ABSTRACTDiabetes mellitus (DM) is a chronic metabolic disease characterized by microvascular and macrovascular complications. Quercetin (3,3?,4?,5,7 pentahydroxyflavone) is a flavonoid that has antioxidant, antiinflammatory and antitumoral effects. This study aimed to determine biochemical and histopathological changes in cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) levels at the end of Quercetin treatment in the streprozosin-induced diabetic rats.In this study forty Wistar Albino male rats aged 8-10 weeks were used. The rats were randomized into four groups. Group-I as control group: citrate buffer, Group-II as sham group: citrate buffer +tween solution, Group-III as diabetic group and Group-IV as diabetic+quercetin group were assigned (n=10 in each group). After the intraperitoneally injection of 0,1 mol/L citrate buffer for 3 days to the Group-I and Group-II rats, % 0,2 tween solution was injected to sham group rats intraperitoneally twice a day for fourteen days.Group-III and Group-IV rats were injected 40 mg/kg streptozotocin dissolved in 0,1 mol/L citrate buffer (pH: 4,5) intraperitoneally for 3 days and diabetes was induced in rats. The rats in Group-IV were given dose of 50 mg/ kg/ day Quercetin dissolved in % 0,2 tween solution intraperitoneally for 14 days twice a day and the protective effects of the Quercetin was investigated.When the 3 groups were compared with control group (Group I) , in the diabetic group rats (Group-III) serum IL-6, tissue COX-2 and iNOS levels increased significantly. Histopathological analysis demonstrated mild inflammation in diabetic group rats (Group-III). Quercetin treatment decreased serum IL-6, tissue COX-2 and iNOS levels; it suppressed the inflammation in liver, kidney and aort tissues.These results suggest that Quercetin might be useful in order to prevent development of diabetes and its complications.Key words: Diabetes mellitus, Quercetin, Cyclooxygenase-2, Inducible Nitric Oxide Synthase.