We determined the effects of helium-neon (He-Ne) laser irradiation on wound healing dynamics in mice treated with steroidal and nonsteroidal anti-inflammatory agents. Male albino mice, 28-32 g, were randomized into 6 groups of 6 animals each: control (C), He-Ne laser (L), dexamethasone (D), D + L, celecoxib (X), and X + L. D and X were injected im at doses of 5 and 22 mg/kg, respectively, 24 h before the experiment. A 1-cm long surgical wound was made with a scalpel on the abdomens of the mice. Animals from groups L, D + L and X + L were exposed to 4 J (cm 2 ) -1 day -1 of He-Ne laser for 12 s and were sacrificed on days 1, 2, or 3 after the procedure, when skin samples were taken for histological examination. A significant increase of collagen synthesis was observed in group L compared with C (168 ± 20 vs 63 ± 8 mm 2 ). The basal cellularity values on day 1 were: C = 763 ± 47, L = 1116 ± 85, D = 376 ± 24, D + L = 698 ± 31, X = 453 ± 29, X + L = 639 ± 32 U/mm 2 . These data show that application of L increases while D and X decrease the inflammatory cellularity compared with C. They also show that L restores the diminished cellularity induced by the anti-inflammatory drugs. We suggest that He-Ne laser promotes collagen formation and restores the baseline cellularity after pharmacological inhibition, indicating new perspectives for laser therapy aiming to increase the healing process when anti-inflammatory drugs are used.

The investigation of resistance vessels is generally costly and difficult to execute. The present study investigated the diameters and the vascular reactivity of different segments of the rat tail artery (base, middle, and tail end) of 30 male Wister rats (EPM strain) to characterize a conductance or resistance vessel, using a low-cost simple technique. The diameters (mean ± SEM) of the base and middle segments were 471 ± 4.97 and 540 ± 8.39 µm, respectively, the tail end was 253 ± 2.58 µm. To test reactivity, the whole tail arteries or segments were perfused under constant flow and the reactivity to phenylephrine (PHE; 0.01-300 µg) was evaluated before and after removal of the endothelium or drug administration. The maximal response (E max ) and sensitivity (pED 50 ) to PHE of the whole tail and the base segment increased after endothelium removal or treatment with 100 µM L-NAME, which suggests modulation by nitric oxide. Indomethacin (10 µM) and tetraethylammonium (5 mM) did not change the E max or pED 50 of these segments. PHE and L-NAME increased the pED 50 of the middle and the tail end only and indomethacin did not change pED 50 or E max . Tetraethylammonium increased the sensitivity only at the tail end, which suggests a blockade of vasodilator release. Results indicate that the proximal segment of the tail artery possesses a diameter compatible with a conductance vessel, while the tail end has the diameter of a resistance vessel. In addition, the vascular reactivity to PHE in the proximal segment is nitric oxide-dependent, while the tail end is dependent on endothelium-derived hyperpolarizing factor.

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Coronary artery (CA) remodeling may lead to increased arterial stiffness and decreased coronary flow reserve. The molecular mechanisms that dictate diabetes‐induced CA remodeling are undefined. This study established a link between oxidative stress, angiotensin II (Ang II), CA remodeling and stiffness in Type 2 diabetic mice. CA (<100 μ) were isolated from 16 wk heterozygous (Db/db) and diabetic (db/db) mice ± treatment with the NADPH‐oxidase inhibitor apocynin (5mM) or the AT1R blocker candesartan (1mg/kg/day). Mean arterial pressure, measured by telemetry, was similar between groups. CA were mounted on a pressure myograph for measurement of structural and passive mechanical properties. Significant inward remodeling was detected in db/db vs. Db/db, defined by increased wall thickness, media:lumen ratio, remodeling index and decreased compliance. This inward remodeling in db/db CA was associated with increased oxidative stress and collagen accumulation as measured by DHE and picrosirius red staining respectively. Immunoblot analysis indicted that basal JNK, ERK, and AKT phosphorylation were increased in db/db CA tissue lysates vs. Db/db. In vivo treatment with apocynin or candesartan reduced inward CA remodeling. These data suggest that increased oxidative stress and Ang II is critical for altered structural and functional remodeling of CA in Type 2 diabetes. Supported by HL056046 and P20RR18766 (PAL).

AimsLittle is known about Type 2 diabetes‐induced structural remodeling of mesenteric resistance arteries. This study compared structural differences in small mesenteric resistance arteries in diabetic (db/db) and control (Db/db) mice.MethodsVessels were isolated from 16wk old mice and structural properties were assessed by pressure myography. Mean arterial pressure (MAP) was measured in vivo by telemetry. Western blot analysis and gelatin zymography were used to assess the expression and activity of matrix regulatory proteins.ResultsMAP was similar between control and db/db mice. Fasting blood glucose levels were higher in db/db mice (505±28 mg/dl) vs. control (115±10, p<0.001). The lumen diameter (121±5.5 μm vs. 77.8±5.5, p<0.001 at 75 mmHg) and media cross‐sectional area were significantly increased in db/db compared to control, respectively, suggesting hypertrophic outward remodeling. Cross‐sectional compliance was significantly larger in the diabetic arteries at 50 and 75 mmHg. The stress‐strain curve was shifted to the right in mesenteric arteries from diabetic mice compared with controls. The expression of the matrix regulatory proteins MMP‐9, MMP‐12, TIMP‐1, TIMP‐2, TGF‐β and PAI‐1 were increased in db/db arteries, while MMP‐2 activity was decreased.ConclusionsThese data suggest that diabetic mesenteric resistance arteries undergo hypertrophic outward remodeling, increased vessel compliance and reduced stiffness that was associated with ECM turnover secondary to an imbalance between pro and anti‐fibrotic factors. Supported by COBRE P20RR18766 and HL56046 (PAL) and CAPES (DV).

The effects of antioxidants on Type 2 diabetes‐induced remodeling of mesenteric resistance arteries are not well known. This study identified structural changes found in small mesenteric resistance arteries in the diabetic (db/db) mouse model. Effects of a membrane permeable free radical scavenger (Tempol, 1 mM) and the NAD(P)H oxidase inhibitor (apocynin, 5 mM) on blood pressure (MAP, measured by telemetry), glucose levels (Accu‐Chek) and vascular structure (pressure myography) were assessed in 16 wk db/db and Db/db (control) mice with or without 4 wks of treatment. MAP was similar between Db/db and db/db mice and unaffected by drug treatment. Fasting blood glucose levels were higher in db/db mice (Db/db 115±10 vs. db/db 505±28 mg/dl, p<0.001). The lumen diameter (Db/db 107±7.5; db/db 131±5 microns, p〈0.05 at 75 mm Hg) and the media cross‐sectional area were increased in db/db compared to Db/db, suggesting hypertrophic outward remodeling. Treatment of db/db mice with Tempol reduced the growth index by 45% and apocynin by 56% compared to untreated db/db. Oxidative stress, measured by electron spin resonance with CMH as spin trap, was increased in db/db and was reversed by Tempol or apocynin. These data suggest that oxidative stress plays an important role in diabetes‐induced hypertrophic vascular remodeling of resistance arterioles. Supported by COBRE P20RR18766 and HL056046 (PAL) and CAPES (DV).

We tested the hypothesis that histamine‐induced endothelial barrier dysfunction is associated with disruption of normal actin dynamics at the endothelial cell periphery. Human umbilical vein endothelial cells (HUVEC) were transfected with GFP‐actin (500 ng vector/5 × 105 cells). Transendothelial resistance (TER) served as an index of barrier function. Time‐lapse image sets were acquired before and after the addition of 10 μM histamine. GFP‐actin expression slightly enhanced histamine‐induced endothelial barrier dysfunction, but did not affect the time course. GFP‐actin was found in cortical fibers moving centrally at a mean rate of 63 nm/min, and in membrane ruffles protruding outward at a mean rate of 1462 nm/min. New cortical fibers formed at a frequency of 0.59/min., and membrane ruffling occurred at a frequency of 0.61 events/min. GFP‐actin also localized in small lamellipodia on the cell periphery. Histamine treatment caused a sudden, coordinated formation of lamellipodia around the cell perimeter, followed by inactivity during the time frame of histamine‐induced barrier dysfunction. Shortly after, lamellepodia and membrane ruffling were restored. The data show that histamine‐indcued barrier dysfunction is associated with a loss of normal cortical actin dynamics in endothelial cells. Supported by NIH RR‐018766 and a grant from the American Heart Association.