engleski

Antioxidative and antidiabetic effects of quercetin in alloxan-induced diabetic mice

Diabetes mellitus is associated with a high production of reactive oxygen species, which may cause oxidative DNA damage. High levels of genomic damage have been associated with liver and renal failure as well as immune-system decline. Quercetin, as an important antioxidants and anti-inflammatory flavonoid, is effective against oxidative stress and may protect against several chronic diseases including diabetes. This study used the comet assay to assess the levels of DNA damage in blood, liver and kidney cells in untreated and quercetin (QU) treated diabetic mice. The antioxidant capacity of QU in vitro was evaluated using three assays which cover different aspects of antioxidant activity. In addition, the study was designed to establish whether QU might have a biological effect in protecting diabetic mice against oxidative stress by using survival studies to observe total body injury at the organism level. QU was injected to mice intraperitoneally (i.p.) at a dose of 50 mg kg-1 for 7 days starting 2 days after a single dose (75 mg kg-1, i.v.) alloxan injection. Alloxan-injected mice showed a rapid reduction in body weight and a marked increase in oxidative stress in liver, kidney and blood homogenate, as determined by lipid peroxidation and comet assay. Histopathological observation of the liver sections of alloxan-induced diabetic mice showed several lesions including cellular vacuolization, cytoplasmic eosinophilia and lymphocyte infiltrations, but with individual variability. Renal histology showed corpuscular, tubular and interstitial changes in alloxan-induced diabetic mice. QU treatment resulted in a significant increase in the body weight, hematological and immunological parameters of blood, as well as leading to 100% survival of diabetic mice. Furthermore, QU had protective effects against alloxan-induced DNA-damage in peripheral lymphocytes and resulted in a significant decrease in lipid peroxidation level in blood plasma and liver. Treatment of diabetic mice with QU resulted in decreased number of vacuolated cells and degree of vacuolization of the liver tissue but did not improve renal histopathology in diabetic mice. The protective role of QU against the ROS induced damages in diabetic mice gives a hope that it may have similar protective action in humans.

Quercetin ; Alloxan ; Diabetes ; Oxidative stress, DNA damage ; Mice

nije evidentirano