Topical retinol attenuates stress-induced ageing signs in human skin ex vivo, throughEGFR activation viaEGF, but notERK andAP-1 activation.

Stress-induced oxidative damage and the inflammatory response lead to degradation of collagen and elastic fibres and wrinkle formation. Topical retinol (or vitamin A) can be a strategy to attenuate the effects of stress in skin as it promotes collagen and elastic fibre production and reduces protease synthesis. This study investigated the effect of topical retinol in stressed human skin using in vitro and ex vivo models. Human skin explants were treated with high levels of epinephrine (as observed in stressed patients) and topically with retinol for 13 days. Human dermal fibroblasts were treated with conditioned medium of ex vivo retinol-treated and non-stressed (without epinephrine) human skin for 24 hours. In ex vivo human skin, retinol reversed the epinephrine-induced reduction in epidermal proliferation and differentiation, normalizing epidermal thickness. Retinol also inhibited the epinephrine-induced reduction in elastic fibre deposition and organization, restoring dermal thickness. In addition, retinol reversed the epinephrine-induced increase in c-JUN protein expression, but it did not alter extracellular signal-regulated kinase 1/2 (ERK) phosphorylation in ex vivo human skin. Conditioned medium of ex vivo retinol-treated and non-stressed human skin presented an increased protein expression of epidermal growth factor (EGF). In human dermal fibroblasts, conditioned medium of ex vivo retinol-treated and non-stressed human skin increased protein and gene expression of fibrillin-1 and protein expression of EGF receptor (EGFR). In conclusion, topical retinol attenuates stress-induced skin ageing signs in human skin ex vivo, probably through EGFR activation via EGF, but not by the stress-activated ERK 1/2 and c-JUN pathways.

Manual Mobilization of Subcutaneous Fibrosis in Mice.

OBJECTIVE: The aim of this study was to induce the remodeling of subcutaneous fibrosis in mice by the manual mobilization of skin and subcutaneous tissue. METHODS: Seven days after the induction of subcutaneous fibrosis, mice were divided into 3 groups: control, stretch, and manual mobilization. Stretch was achieved by elongating the trunk, and manual mobilization was achieved by using the indicator fingertip of both hands, side by side, touching the back and performing a brief stretch. Stretch or manual mobilization was performed once a day for 7 days. RESULTS: Fibrosis was present in the subcutaneous tissue of control animals, whereas brief stretch and manual mobilization were found to reduce fibrosis. CONCLUSIONS: Mechanical stimulation through manual mobilization, or brief stretching, reduced subcutaneous fibrosis after tissue injury.

Viability of randomized skin flaps-an experimental study in rats.

BACKGROUND: Randomized skin flaps are extensively used in plastic surgery, but the possibility of necrosis has challenged their use. Several studies have been conducted aiming to find ways to reduce the occurrence of necrosis. We evaluated the effects of pentoxifylline (PTX) and hyaluronidase (HLD), each alone or combined, on randomized rat skin flaps. MATERIALS AND METHODS: Fifty male Wistar rats were divided into five groups of 10 animals each: control I, control II, PTX, HLD, PTX-HLD. Substances were administered from the first to the 14th postoperative day. The necrotic area was measured on the seventh and 14th postoperative day; the animals were killed on the 14th day, when samples were collected for histologic and immunohistochemical examination. RESULTS: On the seventh day, percentage of the necrotic area was significantly reduced in PTX, HLD, and PTX-HLD animals compared with control groups. On 14th day, percentage of the necrotic area in PTX, HDL, and PTX-HLD groups was also significantly reduced compared with control groups. PTX and PTX-HLD showed a significant reduction in dermis cellularity, VV of macrophages, and myofibroblasts compared with control groups; PTX showed a significant enhancement of LV of blood vessels compared with all other groups. CONCLUSIONS: The use of each substance alone or combined increased flap viability compared with control groups. On the seventh day, PTX exhibited lower viability than HLD, whereas on the 14th day there was no difference between treated groups. PTX alone enhanced the LV of blood vessels, whereas PTX-HLD did not. However, PTX-HLD was more effective in decreasing the dermis cellularity and macrophage VV than HLD alone.

Exercise prior to, but not concomitant with, stress reverses stress-induced delayed skin wound healing.

Stress-induced prolonged inflammation impairs cutaneous wound healing. Exercise may inhibit this effect via an anti-inflammatory mechanism. Our aim was to investigate the effect of moderate exercise on skin wound healing in chronically stressed mice. Mice were trained five times per week on a treadmill or received no training. Mice underwent daily rotational stress from the 6th week until euthanasia. During the 8th week, two wounds were created in the dorsum and collected 10 days later. A control group only received wounds. Exercise was performed prior to and simultaneous with stress for 2 weeks or only prior to stress. Stress increased normetanephrine levels 10 days after wounding, resulting in an increased amount of inflammatory cells and reduced expression of inflammatory cytokines as well as angiogenesis, myofibroblast differentiation and matrix deposition. Concomitant exercise and stress potentiated these effects, intensifying the delayed wound contraction. When exercise was performed only prior to stress, however, the mice showed reduced inflammatory cells in granulation tissue 10 days after wounding and improved wound healing compared with animals with exercise and concomitant stress. Moderate exercise in association with stress potentiates the stress effect; however, when exercise was performed prior to stress, wound healing was improved.

Time Course of the Phenotype of Blood and Bone Marrow Monocytes and Macrophages in the Lung after Cigarette Smoke Exposure In Vivo.

Alveolar macrophages play a central role in the pathogenesis of chronic obstructive pulmonary disease (COPD). Monocytes are recruited from blood during inflammation and then mature into alveolar macrophages. The aim of this study was to investigate the effect of cigarette smoke (CS) at different times in lung macrophages and monocytes from blood and bone marrow in mice. Male mice (C57BL/6, n = 45) were divided into groups: control, CS 5 days, CS 14 days and CS 30 days. Five days' CS exposure induced a pronounced influx of neutrophils and macrophages in the lung associated with increased levels of keratinocyte chemoattractant (KC), tumor necrosis factor-α (TNF-α), nitric oxide (NO) and matrix metalloproteinase (MMP)-12. After 14 days of CS exposure, neutrophil recruitment and cytokine production were greatly reduced. Moreover, chronic CS exposure led to increased recruitment of macrophages (with high expression of CD206), transforming growth factor-ß (TGF-ß) production as well as no detection of TNF-α, interleukin (IL)-6 and KC. CS can also change the monocyte phenotype in the blood and bone marrow, with an increase in Ly6Clow cells. These results show for the first time that CS can change not only macrophage polarization but also monocyte. These results suggest that continued recruitment of Ly6Clow monocytes may help the distinct renewing macrophage M2 population required for COPD progression.

Low-level red laser improves healing of second-degree burn when applied during proliferative phase.

The aim of this study was to investigate the effects of low-level red laser on tissue repair in rats submitted to second-degree burn, evaluating if the timing of laser treatment influences the healing process. The animals had their backs shaved and divided as follows: control group (n = 12)-rats burned and not irradiated, early laser group (n = 12)-rats burned and irradiated from day 1 after injury for five consecutive days, and late laser group (n = 14)-rats burned and irradiated from day 4 after injury for five consecutive days. Laser irradiation was according to a clinical protocol (20 J/cm(2), 100 mW, continuous wave emission mode, 660 nm) as recommended by the laser device manufacturer. Half of the animals were sacrificed 10 days after burn, and the other animals were sacrificed 21 days after burn. The late laser group accelerated wound contraction 10 and 21 days after burn. The late laser group accelerated reepithelialization 18 days after burn. The late laser group increases the granulation tissue 10 and 21 days after burn. Both irradiated groups increased type III collagen expression and TGF-ß 21 days after burn. Both irradiated groups increased macrophage and myofibroblast numbers 10 days after burn and decreased 21 days after. Low-level red laser exposure contributes to the process of tissue repair of second-degree burns, but the intervention during proliferative phase is crucial in the final outcome of the repair process.

Deletion of the α2A/α2C-adrenoceptors accelerates cutaneous wound healing in mice.

The α2-adrenoceptors regulate the sympathetic nervous system, controlling presynaptic catecholamine release. However, the role of the α2-adrenoceptors in cutaneous wound healing is poorly understood. Mice lacking both the α2A/α2C-adrenoceptors were used to evaluate the participation of the α2-adrenoceptor during cutaneous wound healing. A full-thickness excisional lesion was performed on the dorsal skin of the α2A/α2C-adrenoceptor knockout and wild-type mice. Seven or fourteen days later, the animals were euthanized and the lesions were formalin-fixed and paraffin-embedded or frozen. Murine skin fibroblasts were also isolated from α2A/α2C-adrenoceptor knockout and wild-type mice, and fibroblast activity was evaluated. The in vivo study demonstrated that α2A/α2C-adrenoceptor depletion accelerated wound contraction and re-epithelialization. A reduction in the number of neutrophils and macrophages was observed in the α2A/α2C-adrenoceptor knockout mice compared with wild-type mice. In addition, α2A/α2C-adrenoceptor depletion enhanced the levels of nitrite and hydroxyproline, and the protein expression of transforming growth factor-ß and vascular endothelial growth factor. Furthermore, α2A/α2C-adrenoceptor depletion accelerated blood vessel formation and myofibroblast differentiation. The in vitro study demonstrated that skin fibroblasts isolated from α2A/α2C-adrenoceptor knockout mice exhibited enhanced cell migration, α-smooth muscle actin _protein expression and collagen deposition compared with wild-type skin fibroblasts. In conclusion, α2A/α2C-adrenoceptor deletion accelerates cutaneous wound healing in mice.

Gonadal hormones differently modulate cutaneous wound healing of chronically stressed mice.

Gonadal hormones influence physiological responses to stress and cutaneous wound healing. The aim of this study was to investigate the role of gonadal hormones on cutaneous wound healing in chronically stressed mice. Male and female mice were gonadectomized, and after 25 days, they were spun daily at 115 rpm for 15 min every hour until euthanasia. Twenty-eight days after the gonadectomy, an excisional lesion was created. The animals were killed 7 or 14 days after wounding, and the lesions were collected. Myofibroblast density, macrophage number, catecholamine level, collagen deposition, and blood vessel number were evaluated. In the intact and gonadectomized groups, stress increased the plasma catecholamine levels in both genders. In intact groups, stress impaired wound contraction and re-epithelialization and increased the macrophage number in males but not in females. In addition, stress compromised myofibroblastic differentiation and blood vessel formation and decreased collagen deposition in males but not in females. In contrast to intact mice, wound healing in ovariectomized female mice was affected by stress, while wound healing in castrated male mice was not. In conclusion, gender differences contribute to the cutaneous wound healing of chronically stressed mice. In addition, androgens contribute to the stress-induced impairment of the healing of cutaneous wounds but estrogens inhibit it.

Supplementation with olive oil, but not fish oil, improves cutaneous wound healing in stressed mice.

Supplementation with olive and fish oils reverses the effects of stress on behavioral activities and adrenal activation. However, previous studies have not shown whether supplementation with olive and fish oil could inhibit the effects of stress on cutaneous wound healing. Thus, this study investigated the effects of supplementation with fish or olive oil on cutaneous healing in stressed mice. Mice were subjected to rotational stress and treated with olive or fish oil daily until euthanasia. An excisional lesion was created on each mouse, and 14 days later, the lesions were analyzed. In addition, murine skin fibroblasts were exposed to elevated epinephrine levels plus olive oil, and fibroblast activity was evaluated. In the in vivo studies, administration of olive oil, but not fish oil, inhibited stress-induced reduction in wound contraction, reepithelialization, hydroxyproline levels, and blood vessel density. Stress-induced increases in vascular endothelial growth factor expression and the numbers of macrophages and neutrophils were reversed only by olive oil. Both oils reversed stress-induced increase in catecholamine levels and oxidative damage. In in vitro studies, olive oil treatment reversed the reduction in fibroblast migration and collagen deposition and the increase in lipid peroxidation induced by epinephrine. In conclusion, supplementation with olive oil, but not fish oil, improves cutaneous wound healing in chronically stressed mice.

Expression of DNA repair genes in burned skin exposed to low-level red laser.

Although red laser lights lie in the region of non-ionizing radiations in the electromagnetic spectrum, there are doubts whether absorption of these radiations causes lesions in the DNA molecule. Our aim was to investigate the expression of the genes involved with base excision and nucleotide excision repair pathways in skin tissue submitted to burn injury and exposed to low-level red laser. Wistar rats were divided as follows: control group-rats burned and not irradiated, laser group-rats burned and irradiated 1 day after injury for five consecutive days, and later laser group-rats injured and treated 4 days after injury for five consecutive days. Irradiation was performed according to a clinical protocol (20 J/cm(2), 100 mW, continuous wave emission mode). The animals were sacrificed on day 10, and scarred tissue samples were withdrawn for total RNA extraction, complementary DNA (cDNA) synthesis, and evaluation of gene expression by quantitative polymerase chain reaction. Low-level red laser exposure (1) reduces the expression of APE1 messenger (mRNA), (2) increases the expression of OGG1 mRNA, (3) reduces the expression of XPC mRNA, and (4) increases the expression of XPA mRNA both in laser and later laser groups. Red laser exposure at therapeutic fluences alters the expression of genes related to base excision and nucleotide excision pathways of DNA repair during wound healing of burned skin.

Nicotine affects cutaneous wound healing in stressed mice.

Stress is an important condition of modern life. Nicotine addiction can modulate the physiological response to stress. Cutaneous healing is a complex process resulting in scar formation, which can be delayed by stress. Therefore, the aim of this study was to investigate the effects of nicotine administration on cutaneous wound healing in chronically stressed mice. Male mice were submitted to rotational stress, whereas control animals were not subjected to stress. These stressed and control animals were treated with a transdermal nicotine patch that was changed every day. A full-thickness excisional lesion was also generated, and 14 days later, lesions had recovered. However, the Stress + Nicotine group presented a delay in wound contraction. These wounds showed a decrease in inflammatory cell infiltration and lower expression of transforming growth factor-ß (TGF-ß), whereas there was an increase in angiogenesis and tumor necrosis factor-α (TNF-α) expression. In vitro fibroblast migration was also impaired by the nicotine treatment of stressed-stimulated cells. In conclusion, nicotine administration potentiates the delay in wound closure observed in mice submitted to stress.

Insulin resistance impairs cutaneous wound healing in mice.

Obesity is associated with significant changes in skin combined with metabolic alterations such as insulin resistance. Our aim was to investigate the effects of insulin resistance induced by a high-fat diet on cutaneous wound healing. Male C57BL/6 mice were fed standard chow (SC group) or high-fat chow (HFC group) for 30 weeks. On day 0 (28th week), an excisional wound was performed. After 14 days (30th week), the mice were euthanized. Starting from the 8th week, the HFC group had a higher body weight. The HFC group became intolerant to glucose, resistant to insulin, and presented increased plasma cholesterol and triglyceride levels. The wound area was greater in the HFC group. The inflammatory infiltrate and the amount of "fibroblast-like" cells increased in superficial regions of the lesions in the HFC group. The collagen fibers were more organized and denser in the SC group. Hydroxyproline levels were lower in the HFC group. The nitric oxide synthase-2-positive cells were higher in the HFC group. Lipid peroxidation and protein carbonyl levels were higher in the HFC group. The expression levels of alpha-smooth muscle actin and transforming growth factor-ß were higher in the HFC group. These findings support the hypothesis that insulin resistance leads to delayed cutaneous wound healing.

Female, but not male, mice show delayed cutaneous wound healing following aspirin administration.

Cyclo-oxygenase (COX) is an enzyme that participates in the wound healing process. Aspirin, a non-steroidal anti-inflammatory drug, simultaneously inhibits the aromatase activity of COX-1 and COX-2 isoforms, which is needed for prostaglandin synthesis. The aim of the present study was to determine whether aspirin, and thus COX inhibition, distinctly affects cutaneous wound healing in female and male mice. Female and male BALB/c mice were treated with aspirin (25 mg/kg per day) for 16 days until they were killed. The control group received vehicle (saline) only. A full-thickness excisional lesion was made on the back, 2 days after aspirin administration started, and macroscopic, histological and biochemical parameters were evaluated. Sections were stained and immunostained for microscopic analysis. Myeloperoxidase (MPO) activity, hydroxyproline quantity and the protein expression of von Willebrand factor (vWF) and vascular endothelial growth factor (VEGF) were also determined. Female control and aspirin-treated groups exhibited delayed wound closure and re-epithelization compared with the male control and aspirin-treated groups, respectively. The female control group exhibited reduced MPO activity and a decreased number of macrophage inhibitory factor-positive cells compared with the male control group. In the female aspirin-treated group, MPO activity and the number of F4/80-positive macrophages was higher than in the control group. Collagen was reduced only in the female aspirin-treated group. The expression of vWF and VEGF protein was increased in the female aspirin-treated group. In conclusion, aspirin administration impaired the wound healing process in BALB/c female, but not male, mice.

Dermal dendritic cell population and blood vessels are diminished in the skin of systemic sclerosis patients: relationship with fibrosis degree and disease duration.

Recent studies have suggested that the number of dermal dendritic cells is altered in the skin of patients with scleroderma and that these cells may have an important role in the pathogenesis of this disease. There is also a belief that insufficient blood flow to the affected organs may also be responsible for the disease. Our aim was to quantify CD34+ cells, factor XIIIa cells, and blood vessels in the skin of patients with systemic sclerosis and to correlate these data with fibrosis degree and duration of disease. Paraffin-embedded skin sections from patients with systemic sclerosis and from healthy subjects were immunolabelled with antibodies against CD34+ and factor XIIIa. Cells and blood vessels were quantified in the papillary and reticular dermis. Both, the number of CD34+ cells and factor XIIIa cells in the skin of patients with systemic sclerosis were reduced. The reduction of these cell types preceded the appearance of intense fibrosis, suggesting that fibrosis is not responsible of this phenomenon. Blood vessel volume and surface density were also reduced in the skin of systemic sclerosis patients. This reduction was also noted early in the evolution of the disease. Our results suggest that CD34+ cells and factor XIIIa cells may contribute to normal regulation of extracellular matrix assembly. We confirmed the observation that capillary density is diminished in scleroderma skin.

Stress-induced epinephrine levels compromise murine dermal fibroblast activity through ß-adrenoceptors.

Stress-induced catecholamine impairs the formation of granulation tissue acting directly in fibroblast activity; however, the mechanism by which high levels of catecholamines alter the granulation tissue formation is still unclear. Thus, the aim of this study was to investigate how high levels of epinephrine compromise the activity of murine dermal fibroblasts. Dermal fibroblasts isolated from the skin of neonatal Swiss mice were preincubated with α- or ß-adrenoceptor antagonists. Thereafter, cells were exposed to physiologically elevated levels of epinephrine or epinephrine plus α- or ß-adrenoceptor antagonists, and fibroblast activity was evaluated. The blockade of ß1- and ß2-adrenoceptors reversed the increase in fibroblast proliferation, ERK 1/2 phosphorylation, myofibroblastic differentiation and the reduction of collagen deposition induced by epinephrine. In addition, the blockade of ß3-adrenoceptors reversed the increase in fibroblast proliferation and nitric oxide synthesis as well as the reduction of fibroblast migration, AKT phosphorylation and active matrix metalloproteinase-2 expression induced by epinephrine. However, the blockade of α1- and α2-adrenoceptors did not alter the effects of epinephrine on the activity of murine dermal fibroblasts. In conclusion, high levels of epinephrine directly compromise the activity of neonatal mouse skin fibroblasts through the activation of ß1-, ß2- and ß3-adrenoceptors, but not through α1- and α2-adrenoceptors.

Both obesity-prone and obesity-resistant rats present delayed cutaneous wound healing.

Diet-induced overweight rats exhibit delayed cutaneous healing; however, when receiving an obesogenic diet, some rats are susceptible to developing the overweight phenotype, whereas others are resistant. We investigated cutaneous healing in diet-induced obesity (DIO)-prone and diet-resistant (DR) rats. Male rats were fed with a standard (control) or a high-saturated fat (30 % fat, w/w) diet for 20 weeks. Then, the experimental group was subdivided into DIO (n 17) and DR (n 16) groups. An excision lesion was made, and the animals were killed 7 or 14 d later. The average body weight was 29 and 25 % higher in the DIO group compared with the C and DR groups. Retroperitoneal fat was higher in the DIO group than in the control and DR groups (518 and 92 %) and was higher in the DR group than in the control group (223 %). The DIO group presented glucose intolerance, and both the DIO and DR groups presented delayed wound contraction (50 %) and re-epithelialisation (20 %). Compared with the DR group, the DIO group displayed higher amounts of inflammatory cells as well as higher levels of lipid peroxidation (P < 0·05). Myofibroblastic differentiation and vessel remodelling were delayed in both the DIO and DR groups. Nitrite levels were lower in the DIO group (340 % less) than in the DR group. TNF-α expression was increased in the DIO group (130 %) compared with the DR group. Our results showed that DIO as well as DR rats present delays in cutaneous wound healing, even though the DR group does not have an overweight phenotype.

An ex vivo model of human skin photoaging induced by UVA radiation compatible with summer exposure in Brazil.

Skin is the largest body organ and can be affected by several factors, such as ultraviolet (UV) radiation. UV radiation is subdivided in UVA, UVB and UVC according to the radiation wavelength. UVC radiation does not cross the ozone layer; UVB cause DNA damage and is closely related to carcinogenesis; UVA radiation penetrates deeply into the skin, reaching epidermis and dermis and is considered the main promoter of skin aging, known as photoaging. In order to understand photoaging mechanisms and propose efficient therapies, several photoaging study models have been developed, each with benefits and limitations, but most of them use very high doses of UVA radiation, which is not compatible with our daily sun exposure. The objective of this work was to develop a human ex vivo photoaging model induced by UVA exposure compatible to a summer in Brazil. For this, human skin fragments were obtained from healthy donors who underwent otoplasty surgery and skin explants were prepared and placed in plates, with the epidermis facing upwards. Skin explants were exposed to UVA at 16 J/cm2 carried out by protocols of 2 or 4 exposures. Results showed an increase of oxidative damage, inflammatory cells, collagenolytic and elastolytic MMPs expression as well as a decrease of elastin expression, suggesting that the experimental model based on skin explants is able to evaluate UVA-induced aging in human skin.

Cutaneous wound healing of chronically stressed mice is improved through catecholamines blockade.

Stress impairs cutaneous wound healing; however, it is unclear how beta-adrenoceptors participates in alterations induced by stress on skin wound repair. Therefore, the aim of this study was to investigate the effects of propranolol, a non-selective beta-blocker, administration on cutaneous wound healing of chronically stressed mice. Male mice were spun at 115 rpm for 15 min every hour from three days before wounding until euthanasia. Control animals were not submitted to stress. Stressed and control animals were treated with propranolol dissolved in water; controls received only water. Propranolol administration began one day before wounding and was continued daily until euthanasia. A full-thickness excisional lesion was performed. Seven and fourteen days later, animals were killed, and lesions were formalin-fixed and paraffin-embedded. Sections were stained with hematoxylin-eosin and immunostained against F4/80 to quantify macrophages, alpha-smooth muscle actin to quantify the myofibroblast density and proliferating cell nuclear antigen to quantify the cell proliferation. Furthermore, matrix metalloproteinases (MMP)-2 and MMP-9 activity, nitrite and hydroxyproline levels and tumor necrosis factor-alpha (TNF-alpha) expression were measured in wound. Stress and control + propranolol groups presented a delay in wound contraction, re-epithelialization, F4/80-positive macrophages, neutrophils and mast cells infiltration, cellular proliferation, angiogenesis, myofibroblastic differentiation, MMP-2 and MMP-9 activation and TNF-alpha expression, whereas an increase in the nitrite levels. Stress + propranolol group presented results similar to control group. In conclusion, stress impairs cutaneous wound healing in mice through beta1- adrenoceptors and beta2-adrenoceptors activation.

Rotational stress-induced increase in epinephrine levels delays cutaneous wound healing in mice.

Stress impairs wound healing of cutaneous lesions; however, the mechanism is still unclear. The aim of this study was to evaluate the effects of rotational stress on cutaneous wound healing in mice and propose a mechanism. Male mice were spun at 45 rpm for 15 min every hour beginning 3 days before wounding until euthanasia. Control animals were not subjected to stress. To confirm that catecholamines participate in stress-induced delay of wound healing, mice were treated daily with propranolol. An excisional lesion was created and measured. Seven and 14 days later, animals were killed and lesions collected. Sections were stained with hematoxylin-eosin and immunostained for alpha-smooth muscle actin and proliferating cell nuclear antigen. Matrix metalloproteinase (MMP)-2 and -9 activity, nitrite levels, and tumor necrosis factor-alpha (TNF-alpha) expression were measured in the wounds. In addition, murine skin fibroblast cultures were treated with high levels of epinephrine and fibroblast activity was evaluated. Stressed mice exhibited reduced locomotor activity and increased normetanephrine plasma levels. Rotational stress was associated with decreased wound contraction, reduced re-epithelialization, reduced MMP-2 and MMP-9 activation, but with strongly increased nitrite levels. Furthermore, inflammatory cell infiltration, TNF-alpha expression, myofibroblastic differentiation, and angiogenesis were all delayed in the stress group. Propranolol administration reversed the deleterious effects of stress on wound contraction and re-epithelialization. High epinephrine concentrations increased murine skin fibroblast proliferation and nitric oxide synthesis, and strongly inhibited skin fibroblast migration and both pro- and active MMP-2. In conclusion, rotational stress impairs cutaneous wound healing due to epinephrine increased levels.

Effects of supplementation with different edible oils on cutaneous wound healing.

Fatty acids are bioactive molecules, but their effects on cutaneous wound healing are not well understood. Our aim was to investigate the effects of supplementation with edible oils on cutaneous healing. Thirty days before wounding, rats were started on daily supplements of sunflower oil, linseed oil, fish oil, or water. Supplementation lasted until euthanasia. On day 0, an excisional wound was made on the back of each animal. Fourteen days later, the animals were euthanized, and the wound and adjacent skin were collected. Wound closure was higher in the control group compared with the other groups at days 7 and 14. Inflammatory cells were abundant in the control, linseed, and fish groups, but scarce in the sunflower group. Large numbers of myofibroblasts were observed in the control and sunflower groups. The linseed and fish groups presented a high density of dilated blood vessels. The control and sunflower groups showed a moderate density of collagen fibers; a high density of fibers was observed in the linseed and fish groups. Hydroxyproline levels were lowest in the control and sunflower groups. Supplementation with different types of edible oils delayed wound closure and affected the inflammatory infiltrate and collagen deposition.