Reactive Oxygen Species and Acute Modulation of Albumin Microvascular Leakage in the Microcirculation of Diabetic Rats in vivo

Abstract

Endothelial cells have been reported to generate reactive oxygen species such as the superoxide anion, hydrogen peroxide, and the hydroxyl radical. The aim of this work was to evaluate the role of reactive oxygen species in diabetes-induced changes in vascular permeability. Intravital videomicroscopy was used to study albumin microvascular leakage in the cremaster muscle. The extravasation of a fluorescent macromolecular tracer (FITC-albumin) was measured for 1 h and, after computer-aided image analysis, was expressed as variations of normalized gray levels (arbitrary units). The extravasation of the macromolecular tracer was greater in diabetic rats (5.28 ± 1.29 vs. 1.96 ± 0.41 AU at 1 h in diabetic and control rats, respectively). Administration of superoxide dismutase (SOD), which dismutates ·O^–₂ to H₂O₂, and of catalase which reacts with H₂O₂ to form H₂O and molecular oxygen failed to inhibit the increased extravasation of the macromolecular tracer when administered separately. However, a significant inhibition of diabetic increase in albumin extravasation was found when these 2 drugs were administered simultaneously, and in this case, the extravasation of the macromolecular tracer at 1 h was similar in diabetic rats (2.11 ± 0.61 AU) and normoglycemic rats (1.43 ± 0.48 AU). No difference was found in adherent leukocytes or in the leukocyte rolling flux between diabetic and normoglycemic rats. We conclude that reactive oxygen species are responsible for an increase in microvascular permeability likely via leukocyte-independent mechanisms.

Endothelial Domes Encapsulate Adherent Neutrophils and Minimize Increases in Vascular Permeability in Paracellular and Transcellular Emigration

“…However, at 60 min MIP-2 superfusion, the number of emigrated Mac-1-/- cells was not dissimilar to what was observed in the wild-type mice (Figure 1B). Vascular permeability was measured as the flux of FITC-labeled albumin from the circulation to the interstitial space as we and others have described [18], [19], [20] using computer assisted imaging for quantification. There was a significant increase in permeability over time in response to MIP-2 superfusion in wild-type mice (Figure 1C).…”

“…The degree of vascular albumin leakage from cremasteric venules of Mac-1-/- and wt mice was quantified as described previously by both our laboratory [18] and others [19], [20]. In brief, 25 mg kg −1 FITC-labeled BSA (Sigma-Aldrich) was administered to the mice i.v.…”

Effects of berberine on diabetes induced by alloxan and a high-fat/high-cholesterol diet in rats

“…Hyperglycemia also can degrade antioxidant enzyme defenses, thereby allowing reactive oxygen species to damage cells and tissues. Increase in reactive oxygen species including superoxide anion can result in damage to endothelial cells and an increase in micro-vascular permeability (Bonnardel-Phu and Vicaut, 2000;Kashiwagi et al, 1996). In diabetes highly glycated human oxyhemoglobin, at physiologic plasma glucose concentrations, impairs nitric oxide-mediated reactions by a mechanism involving superoxide anions (Vallejo et al, 2000).…”

Diabetic vascular dysfunction: Links to glucose‐induced reductive stress and VEGF

“…Radical Damage Renewed interest has been placed on the role of oxidative stress in the pathogenesis of diabetic complications (Baynes and Thorpe, 1999;Low et al, 1997;Nishikawa et al, 2000a,b) and the role of ROS in the increased microvascular permeability of diabetes (Bonnardel-Phu and Vicaut, 2000). Increased flux through the sorbitol pathway is associated with increased superoxide formation, increased malondialdehyde, and decreased glutathione (Bravi et al, 1997;De Mattia et al, 1994).…”