Capillary area in early low-dose streptozocin-treated mice.

It has been reported that vasoconstriction of intra-islet capillaries plays an important role in the initiation of the insulitis seen in the islets of Langerhans of diabetic animals. Nevertheless, only a few studies have concentrated on islet vessels. This led us to perform an experiment with the aim to compare the islet capillary area of normal untreated and multiple low-dose streptozocin (LDS) (40 mg/kg b.wt. i.p./5 days)-treated mice. In order to identify endothelial cells a method devised by Gomori, based on the fact that these cells present alkaline phosphatases on their surface, was used. Results revealed that in LDS-treated animals the capillary area per islet is significantly reduced when compared to the vascular area of controls (p less than 0.05). This could be due to a vasoconstriction phenomenon that occurs in the islet capillaries after the streptozocin administration and before the appearance of any inflammation. Our findings could demonstrate that vasoconstriction events are involved in initiation of the diabetic disease.