RESUMO
OBJECTIVES: To investigate the effect of insulin on microvascular responses to inflammatory mediators in a model of type 2 diabetes mellitus. MATERIALS: We used the neonatal streptozotocin (n-STZ)-induced diabetes model. Diabetes was induced in male newborn (2-day-old) Wistar rats through STZ administration. Experiments were performed 10-12 weeks later. METHODS: Rats were divided into control (sham-injected) and study (n-STZ) groups. Using a closed-circuit video camera coupled to a microscope, changes in mesenteric arteriolar and venular diameters induced by topical application of the inflammatory mediators histamine, bradykinin and platelet-activating factor were assessed in chloral hydrate-anesthetized rats. TREATMENT: The n-STZ rats received NPH insulin s.c. for either 4 h or 12 days. RESULTS: Impaired arteriole and venule responses to the inflammatory mediators tested were observed in n-STZ rats. Both acute and chronic insulin treatment corrected the alterations. CONCLUSION: We conclude that insulin is beneficial, restoring microvascular reactivity to inflammatory mediators in type 2 diabetes.