Avaliação da inflamação na pele de membro posterior isquêmico em modelo experimental de diabetes tipo 1

Abstract

Diabetes mellitus is considered a pandemic and is characterized by a high risk of developing vascular complications, among them Peripheral Arterial Disease (PAD). PAD is two to four times more common in diabetics than in non-diabetics and causes a reduction of blood flow in lower limbs (ischemia). The ischemia triggers a vascular and inflammatory response that can lead to the development of diabetic ischemic wounds, which can progress to necrosis and amputation of lower limbs. Thus, we aimed to evaluate the inflammatory activity in the skin of hind limbs after ischemia in diabetic mice. 6 weeks old balb\c mice were divided in two groups: diabetic (STZ) and nondiabetic (Control). Diabetes was induced by 50mg/kg/day of streptozotocin for five days. Hindlimb ischemia was induced by permanent left femoral artery occlusion (FAO). Confirmation of ischemia was done by laser Doppler perfusion imaging and analyzes were carried out 0, 1, 3 and 7 days after the FAO. To assess skin inflammation, we analyzed total and differential leukocyte count in peripheral blood, and in skin we analyzed macrophage and neutrophil infiltration by evaluating NAG and MPO activities, respectively, in ischemic and contralateral non-ischemic skin of hindlimbs. Also evaluated are the main recruiting chemokines these cells, CXCL1 and CCL2, respectively, histopathological sections stained with H&E and the dosage of VEGF. The leukocytes were isolated from brachial plexus and labeled with 99m Tc-ECD and were injected into the tail vein of animals to conduct scintigraphic images and analyzed quantitatively by counting the radioactivity in the regions of interest. The results showed that ischemia was maintained throughout the trial period. In peripheral blood, the diabetic group had lower white blood cell count on the 3º day after FAO (p0,001), if compared with control. The inflammatory score showed that in the skin in the control group had higher score on the 3º day after FAO and in diabetic group the score were higher on 1º day after FAO, wherein the control group had higher concentration of neutrophils on the 3º day (p0,001) and on the 7º day (p0,001) after FAO and diabetic group had had higher concentration of macrophages on the 0 day (p0,01) e 3 (p0,001) after FAO. When assessing the concentration of VEGF, the diabetic group presented a lower on the day 1 (p0,001), 3 (p0,01) e 7 (p0,01) after FAO. In the scintigraphic images there was no difference between groups. Thus, our results suggest that are differences in the inflammatory profile in diabetic and control group. New results will still be required to evaluate the use of radiolabeled leukocytes in the early identification of possible changes in the skin.