Myocardial capillary net and blood constituents in streptozotocin (STZ)-induced diabetic rats

Type 1 diabetes was induced in Wistar rats by injection of streptozotocin (STZ). Changes in the myocardial capillary network were examined using the double-staining enzymatic method for alkaline phosphatase (AP) and dipeptidylpeptidase IV (DPPIV) This method allows the identification of the arteriolar (AP-containing) and the venular (DPPIV-containing) portions of the capillary network. In addition, blood plasma was analysed. The AP- and AP/DPPIV-containing capillary portions increased significantly, accompanied by a decrease in the DPPIV-containing portions in 60 days. A significant increase in AP was observed in the plasma. The capillary domain areas of each capillary portion were larger in the STZ-injected group than in the controls. It appears that oxygen transport to the subendocardial myocardial tissues may be decreased in the STZ group. In rats fed with Saji-supplemented chow there was a decrease in plasma AP, with increases in hemoglobin, hematocrit and vitamin C, suggesting a partial improvement of metabolic function and oxygen supply in these diabetic Wistar rats.