چکیده (انگلیسی):

The aim was to investigate rosiglitazone and metformin effects on some vascular and biochemical
changes associated with streptozotocin (55 mg/kg; i.p.)-induced hyperglycaemia in rats. Isolated
aortas were used to evaluate their reactivity towards norepinephrine, acetylcholine, and sodium
nitroprusside. Blood samples were used to assess the biochemical changes of some parameters viz.,
plasma lipid peroxides and nitric oxide levels and erythrocytic glutathione peroxidase activity. Hyperglycaemic
animals orally received rosiglitazone (0.5 mg/kg) or metformin (150 mg/kg) daily for
2 weeks and their effects were determined 24 h after the last dose. Our results revealed that streptozotocin-
induced hyperglycaemia is associated with impaired vascular reactivity towards various agents,
increased lipid peroxides level, decreased glutathione peroxidise activity, and decreased nitric oxide
level. Both drugs further decreased norepinephrine-induced contraction and improved acetylcholineand
sodium nitroprusside-induced relaxations. Rosiglitazone restored the alterations in all tested biochemical
parameters while metformin restored only glutathione peroxidise activity. In conclusion
both drugs show beneficial effects against the vascular dysfunction associated with hyperglycaemia
which might be related to their euglycaemic activity in addition to anti-oxidant property of rosiglitazone
and a direct effect of metformin on vascular smooth muscle.