Topical Docosahexaenoic Acid (DHA) Accelerates Skin Wound Healing in Rats and Activates GPR120.

BACKGROUND: The development of methods for improving skin wound healing may have an impact on the outcomes of a number of medical conditions. The topical use of polyunsaturated fatty acids (PUFAs) can accelerate skin wound healing through mechanisms that involve, at least in part, the modulation of inflammatory activity. PURPOSE: We evaluated whether G-protein-coupled receptor 120 (GPR120), a recently identified receptor for docosahexaenoic acid (DHA) with anti-inflammatory activity, is expressed in the skin and responds to topical DHA. METHOD: Male Wistar rats were submitted to an 8.0-mm wound on the back and were immediately administered a topical treatment of a solution containing 30 µM of DHA once a day. The healing process was photodocumented, and tissues were collected on Days 5, 9, and 15 for protein and RNA analyses and histological evaluation. RESULTS: GPR120 was expressed in the intact skin and in the wound. Keratinocytes expressed the most skin GPR120, while virtually no expression was detected in fibroblasts. Upon DHA topical treatment, wound healing was significantly accelerated and was accompanied by the molecular activation of GPR120, as determined by its association with ß-arrestin-2. In addition, DHA promoted a reduction in the expression of interleukin (IL) 1ß and an increase in the expression of IL-6. Furthermore, there was a significant increase in expression of transforming growth factor ß (TGF-ß) and the keratinocyte marker involucrin. DISCUSSION: Topical DHA improved skin wound healing. The activation of GPR120 is potentially involved in this process.

Topical 5-azacytidine accelerates skin wound healing in rats.

The development of new methods to improve skin wound healing may affect the outcomes of a number of medical conditions. Here, we evaluate the molecular and clinical effects of topical 5-azacytidine on wound healing in rats. 5-Azacytidine decreases the expression of follistatin-1, which negatively regulates activins. Activins, in turn, promote cell growth in different tissues, including the skin. Eight-week-old male Wistar rats were submitted to 8.0-mm punch-wounding in the dorsal region. After 3 days, rats were randomly assigned to receive either a control treatment or the topical application of a solution containing 5-azacytidine (10 mM) once per day. Photo documentation and sample collection were performed on days 5, 9, and 15. Overall, 5-azacytidine promoted a significant acceleration of complete wound healing (99.7% ± 0.7.0 vs. 71.2% ± 2.8 on day 15; n = 10; p < 0.01), accompanied by up to threefold reduction in follistatin expression. Histological examination of the skin revealed efficient reepithelization and cell proliferation, as evaluated by the BrdU incorporation method. 5-Azacytidine treatment also resulted in increased gene expression of transforming growth factor-beta and the keratinocyte markers involucrin and cytokeratin, as well as decreased expression of cytokines such as tumor necrosis factor-alpha and interleukin-10. Lastly, when recombinant follistatin was applied to the skin in parallel with topical 5-azacytidine, most of the beneficial effects of the drug were lost. Thus, 5-azacytidine acts, at least in part through the follistatin/activin pathway, to improve skin wound healing in rodents.

Hypothalamic inhibition of acetyl-CoA carboxylase stimulates hepatic counter-regulatory response independent of AMPK activation in rats.

BACKGROUND: Hypothalamic AMPK acts as a cell energy sensor and can modulate food intake, glucose homeostasis, and fatty acid biosynthesis. Intrahypothalamic fatty acid injection is known to suppress liver glucose production, mainly by activation of hypothalamic ATP-sensitive potassium (K(ATP)) channels. Since all models employed seem to involve malonyl-CoA biosynthesis, we hypothesized that acetyl-CoA carboxylase can modulate the counter-regulatory response independent of nutrient availability. METHODOLOGY/PRINCIPAL FINDINGS: In this study employing immunoblot, real-time PCR, ELISA, and biochemical measurements, we showed that reduction of the hypothalamic expression of acetyl-CoA carboxylase by antisense oligonucleotide after intraventricular injection increased food intake and NPY mRNA, and diminished the expression of CART, CRH, and TRH mRNA. Additionally, as in fasted rats, in antisense oligonucleotide-treated rats, serum glucagon and ketone bodies increased, while the levels of serum insulin and hepatic glycogen diminished. The reduction of hypothalamic acetyl-CoA carboxylase also increased PEPCK expression, AMPK phosphorylation, and glucose production in the liver. Interestingly, these effects were observed without modification of hypothalamic AMPK phosphorylation. CONCLUSION/SIGNIFICANCE: Hypothalamic ACC inhibition can activate hepatic counter-regulatory response independent of hypothalamic AMPK activation.

Effect of chronic supplementation with shark liver oil on immune responses of exercise-trained rats.

Previous studies have reported that chronic supplementation with shark liver oil (SLO) improves immune response of lymphocyte, macrophage and neutrophil in animal models and humans. In a similar manner, exercise training also stimulates the immune system. However, we are not aware of any study about the association of exercise and SLO supplementation on immune response. Thus, our main goal was to investigate the effect of chronic supplementation with SLO on immune responses of exercise-trained rats. Male Wistar rats were divided into four groups: sedentary with no supplementation (SED, n = 20), sedentary with SLO supplementation (SEDslo, n = 20), exercised (EX, n = 17) and exercised supplemented with SLO (EXslo, n = 19). Rats swam for 6 weeks, 1.5 h/day, in water at 32 +/- 1 degrees C, with a load of 6.0% body weight attached to the thorax of rat. Animals were killed 48 h after the last exercise session. SLO supplementation did not change phagocytosis, lysosomal volume, superoxide anion and hydrogen peroxide production by peritoneal macrophages and blood neutrophils. Thymus and spleen lymphocyte proliferation were significantly higher in SEDslo, EX, and EXslo groups compared with SED group (P < 0.05). Gut-associated lymphocyte proliferation, on the other hand, was similar between the four experimental groups. Our findings show that SLO and EX indeed are able to increase lymphocyte proliferation, but their association did not induce further stimulation in the adaptive immune response and also did not modify innate immunity.

Cardiovascular and pulmonary effects of NOS inhibition in endotoxemic conscious rats subjected to swimming training.

Sepsis is characterized by systemic hypotension, hyporeactiveness to vasoconstrictors, impaired tissue perfusion, and multiple organ failure. During exercise training (ET), dynamic cardiovascular adjustments take place to maintain proper blood pressure and adjust blood supply to different vascular beds. The aim of this study was to investigate whether ET protects against the cardiovascular abnormalities induced by LPS, a model of experimental endotoxemia, and to evaluate the role of nitric oxide (NO) in pulmonary edema. Wistar rats were subjected to swimming training (up to 1 h/day, 5 days/week for 4 weeks) after which their femoral artery and vein were catheterized. LPS (5 mg/kg, i.v.), injected in control (C) and trained animals (ET), promoted 3 distinct phases in mean arterial pressure (MAP) and heart rate (HR). After ET the alterations in MAP were attenuated. The ET animals showed a lower pulmonary edema index (PEI) after LPS (C=0.65+/-0.01; ET=0.60+/-0.02), which was attenuated after treatment with aminoguanidine in both groups (C=0.53+/-0.02; ET=0.53+/-0.02, p<0.05). After l-NAME, PEI was enhanced numerically in the C and was statistically higher in the ET group (C=0.73+/-0.05; ET=1.30+/-0.3, p<0.05). 7-nitroindazole did not promote any alteration in either group. The adaptations promoted by ET seem to be beneficial, counteracting the cardiovascular abnormalities and pulmonary edema seen in septicemia induced by LPS. The results suggest that iNOS aggravates and cNOS protects against this pulmonary edema.

Relação entre aptidão cardiorrespiratória, parâmetros fisiológicos e perceptuais durante caminhada em ritmo auto-selecionado por mulheres adultas sedentárias / Relationship between cardiorrespiratory fitness, physiological and perceptual parameters at self-selected pace walking in sedentary women

O objetivo do presente estudo foi investigar a correlação entre aptidão cardiorrespiratória (ACR) e os parâmetros fisiológicos e perceptuais durante caminhada em ritmo auto-selecionado por mulheres adultas sedentárias. Participaram 41 sujeitos (idade 32,6±8,6 anos), que realizaram inicialmente um teste incremental em esteira, para a determinação dos parâmetros fisiológicos e perceptuais máximos, associados ao limiar ventilatório (LV), e posteriormente um teste de 20 minutos de caminhada em ritmo auto-selecionado. Correlação de Pearson (r) foi empregada para verificar a correlação entre ACR e os parâmetros fisiológicos e perceptuais, utilizando significância de p<0,05. A ACR foi inversamente correlacionada aos valores percentuais dos parâmetros fisiológicos, consumo máximo de oxigênio (%VO2máx; r = -0,77; p<0,01), consumo de oxigênio no LV (%VO2LV; r = -0,57; p<0,01), freqüência cardíaca máxima (%FCmáx; r = -0,50; p<0,01) e freqüência cardíaca no LV (%FCLV; r = -0,66; p<0,01) e diretamente associada ao valor absoluto do consumo de oxigênio (VO2; r = 0,43; p<0,01) durante caminhada em ritmo auto-selecionado. Com relação aos parâmetros perceptuais, a ACR foi inversamente correlacionada à percepção subjetiva de esforço (PSE; r = -0,36; p<0,05). Conclui-se que os sujeitos com menor ACR tendem a auto-selecionar uma maior intensidade de exercício físico apresentando uma maior PSE.

The purpose of this study was to investigate the relationship between cardiorrespiratory fitness (CRF) and physiological and perceptual responses during walking at a self-selected pace in sedentary women. The sample was composed by 41 women with age of 32.6 ± 8.6 years. Subjects participated of an incremental test to determine the maximal physiological and perceptual responses; subjects also participated of a 20 minutes treadmill walking bout at self-selected pace to determine the physiological and perceptual responses. Pearson correlation (r) was used to verify the association between CRF and physiological and perceptual responses during walking, with a level of significance of p<0.05. CRF was inversely associated to percentage of maximal oxygen consumption (%VO2max; r = -0,77; p<0,01), percentage of oxygen consumption at the ventilatory threshold (VT; VO2VT; r = -0,57; p<0,01), percentage of maximal heart rate (HRmax; r = -0,50; p<0,01) and percentage of HR at the VT (HRVT; r = -0,66; p<0,01) (p<0.01) and directly related to maximal oxygen consumption (VO2max; r = 0,43; p<0,01) during walking at a self-selected pace. In summary, the subjects with a lower CRF walked at a higher relative intensity and perceived effort.