EFFECTS OF THE NATURAL FLAVONOID DELPHINIDIN ON DIABETIC MICROANGIOPATHY

The purpose of the present study was to investigate the effects of the flavonoid delphinidin chloride (CAS 528-53-0, IdB 1056) on diabetic m icroangiopathy. Hamsters were injected with alloxan and cheek pouch mi crocirculation was observed by a fluorescent microscopy technique 90 d ays from alloxan. The increase in permeability, the number of adhering leukocytes to venular vessel wall and vasodilatory responses to acety lcholine (Ach) and sodium nitroprusside (SNP) were measured. In diabet ic group microvascular permeability and the number of sticking leukocy tes to the venular endothelium were increased. Vasoconstriction by Ach was observed while the vasodilation by SNP was significantly attenuat ed in diabetic animals. These results are consistent for a decreased r elaxation an suggest also an impairment in the smooth muscle cell func tion in diabetic arterioles. IdB 1056 exhibited an inhibitory effect o n increased microvascular permeability and on leukocytes adhering to t he venular vessels. Indeed, the treatment with IdB 1056 in diabetic ha msters pretreated or not with indometacin, a cyclooxygenase inhibitor, restored the relaxant responses to Ach and SNP. In conclusion, the ef fects of IdB 1056 observed in vivo at the microcirculatory level preve nt the injury to endothelial cell function associated with diabetes an d/or oxidative stress.