The effects of photobiomodulation therapy on Staphylococcus aureus infected surgical wounds in diabetic rats. A microbiological, histopathological, and biomechanical study

ABSTRACT PURPOSE: To evaluate the effects of photobiomodulation therapy (PBMT) at 685 nm on diabetic wound healing in rats suffering from bacterial infection induced by Staphylococcus aureus (S. aureus). METHODS: Thirty streptozotocin-induced diabetic rats were allocated into two groups: control and PBMT. A 4-cm full-thickness linear-incision was made on the dorsal midline and was contaminated with S. aureus. The wounds in the PBMT group were irradiated daily for 5 consecutive days, starting 3 days after the induction and always in the mornings. RESULTS: The result revealed that PBMT resulted in a significant decrease in S. aureus CFU in the PBMT group in comparison to the control group (P<0.05). The length of wounds, in the 2nd and 3rd weeks, in the PBMT group were significantly shorter compared to the control group (P<0.05). PBMT caused a significant increase in the histological parameters in comparison to the control group (P<0.05). Moreover, PBMT significantly increased the breaking strength of the surgical scars produced in the skin of the PBMT group when compared to the control group (P<0.05). CONCLUSION: Photobiomodulation therapy may be useful in the management of wound infection through a significant bacterial growth inhibition and an acceleration of wound healing process.

Effect of Otostegia persica extract on ischemia/reperfusion induced renal damage in diabetic rats. A biochemical study

ABSTRACT PURPOSE: To evaluate the effect of Otostegia persica (O. persica) extract on renal damage induced by ischemia/reperfusion (I/R) in diabetic rats. METHODS: Forty-eight rats were subjected to right nephrectomy; then, they were allocated into six groups: Sham; Diabetic sham; I/R; Diabetic I/R; I/R+O. persica; Diabetic I/R+O. persica. Diabetes was induced by streptozotocin (200 mg/kg, i.p.). O. persica (300 mg/kg/day, p.o) was administered for 2 weeks. On the 15th day, ischemia was induced in left kidney for 60 min, followed by reperfusion for 24h. Renal functional and biochemical markers were estimated. RESULTS: I/R in both normal and diabetic rats, induced a significant elevation in serum levels of urea and creatinine (p<0.05). Renal I/R induced a significant increase of malondialdehyde, myeloperoxidase and nitric oxide concentrations associated with significant reduction in superoxide dismutase and catalase activities in comparison with the sham group (p<0.05). Diabetic rats that underwent renal I/R exhibited a significant increase in all the studied parameters with a reduction in the antioxidant enzymes as compared to nondiabetic rats (p<0.05). These deleterious effects associated with renal I/R were improved by the treatment with O. persica (p<0.05). CONCLUSION: Otostegia persica pretreatment protected the renal injury from ischemia-reperfusion in diabetic rats.

The effects of low level laser therapy on Staphylococcus aureus infected third-degree burns in diabetic rats

PURPOSE: To characterize the effects of low-level laser (LLL) on third-degree burn wounds which were infected with Staphylococcus aureus (S. aureus) in diabetic rats. METHODS: Thirty streptozotocin-induced diabetic rats were divided into two groups: the control and the LLL groups. Third-degree burns were induced using a heated metal rod, and then, were contaminated with S. aureus. The wounds in the LLL group were irradiated with a LLL (685nm) daily for five consecutive days, starting three days after the induction. The wound area was measured at 3, 5, 8, 14 and 21 days after burning. At the end of trial, the skin samples were harvested. RESULTS: Reduction in wound areas in the LLL and control groups were significantly different only on the 21st day (p<0.05). The mean bacterial numbers in the LLL group were significantly lower (p<0.05) than those in the control group. The number of macrophages, new blood vessels, fibroblast, and elevated collagen deposition in the LLL group significantly increased compared to the control group (p<0.05). The mean breaking strength of scars in the control group was significantly lower (p<0.05) than that of the LLL group. CONCLUSION: The low-level laser improved the healing of S. aureus third-degree burn infections in diabetic rats.

Effects of N-acetylcysteine and pentoxifylline on remote lung injury in a rat model of hind-limb ischemia/reperfusion injury / Efeitos da N-acetilcisteína e pentoxifilina na lesão pulmonar remota em um modelo de lesão de isquemia/reperfusão de membro posterior em ratos

Objective : To investigate the effects of N-acetylcysteine (NAC) and pentoxifylline in a model of remote organ injury after hind-limb ischemia/reperfusion (I/R) in rats, the lungs being the remote organ system. Methods : Thirty-five male Wistar rats were assigned to one of five conditions (n = 7/group), as follows: sham operation (control group); hind-limb ischemia, induced by clamping the left femoral artery, for 2 h, followed by 24 h of reperfusion (I/R group); and hind-limb ischemia, as above, followed by intraperitoneal injection (prior to reperfusion) of 150 mg/kg of NAC (I/R+NAC group), 40 mg/kg of pentoxifylline (I/R+PTX group), or both (I/R+NAC+PTX group). At the end of the trial, lung tissues were removed for histological analysis and assessment of oxidative stress. Results : In comparison with the rats in the other groups, those in the I/R group showed lower superoxide dismutase activity and glutathione levels, together with higher malondialdehyde levels and lung injury scores (p < 0.05 for all). Interstitial inflammatory cell infiltration of the lungs was also markedly greater in the I/R group than in the other groups. In addition, I/R group rats showed various signs of interstitial edema and hemorrhage. In the I/R+NAC, I/R+PTX, and I/R+NAC+PTX groups, superoxide dismutase activity, glutathione levels, malondialdehyde levels, and lung injury scores were preserved (p < 0.05 for all). The differences between the administration of NAC or pentoxifylline alone and the administration of the two together were not significant for any of those parameters (p > 0.05 for all). Conclusions : Our results suggest that NAC and pentoxifylline both protect lung tissue from the effects of skeletal muscle I/R. However, their combined use does not appear to increase the level of that protection.

Objetivo : Investigar os efeitos da N-acetilcisteína (NAC) e pentoxifilina em um modelo de lesão pulmonar remota após isquemia/reperfusão (I/R) de membro posterior em ratos. Métodos : Trinta e cinco ratos Wistar machos foram divididos em cinco grupos (n = 7/grupo), cada qual submetido ao seguinte: operação simulada (grupo controle); isquemia de membro posterior, induzida por pinçamento da artéria femoral esquerda por 2 h, seguida por de 24 h de reperfusão (grupo I/R); e isquemia de membro posterior, como descrito acima, seguida de injeção intraperitoneal (antes da reperfusão) de 150 mg/kg de NAC (grupo I/R+NAC), 40 mg/kg de pentoxifilina (grupo I/R+PTX) ou ambas (grupo I/R+NAC+PTX). Ao final do experimento, tecidos pulmonares foram removidos para análise histológica e avaliação do estresse oxidativo. Resultados : Comparados aos ratos dos outros grupos, os do grupo I/R apresentaram menor atividade de superóxido dismutase e menores níveis de glutationa, além de maiores níveis de malondialdeído e maiores escores de lesão pulmonar (p < 0,05 para todos). Infiltração celular inflamatória intersticial dos pulmões também foi bem maior no grupo I/R do que nos outros grupos. Além disso, os ratos do grupo I/R apresentaram vários sinais de edema intersticial e hemorragia. Nos grupos I/R+NAC, I/R+PTX e I/R+NAC+PTX, a atividade de superóxido dismutase, níveis de glutationa, níveis de malondialdeído e escores de lesão pulmonar foram preservados (p < 0,05 para todos). As diferenças entre a administração de NAC ou pentoxifilina isoladamente e a das duas combinadas não foi significativa para nenhum desses parâmetros (p > 0,05 para todos). Conclusões : Nossos resultados sugerem que tanto NAC quanto pentoxifilina protegem o tecido pulmonar dos efeitos de I/R de músculo esquelético. Entretanto, seu uso combinado não parece aumentar o nível dessa proteção.

Tramadol Alleviates Myocardial Injury Induced by Acute Hindlimb Ischemia Reperfusion in Rats / Tramadol Atenua Lesões Miocárdicas Induzidas pela Reperfusão Pós- Isquêmica Aguda de Membros Posteriores em Ratos

AbstractBackground:Organ injury occurs not only during periods of ischemia but also during reperfusion. It is known that ischemia reperfusion (IR) causes both remote organ and local injuries.Objective:This study evaluated the effects of tramadol on the heart as a remote organ after acute hindlimb IR.Methods:Thirty healthy mature male Wistar rats were allocated randomly into three groups: Group I (sham), Group II (IR), and Group III (IR + tramadol). Ischemia was induced in anesthetized rats by left femoral artery clamping for 3 h, followed by 3 h of reperfusion. Tramadol (20 mg/kg, intravenous) was administered immediately prior to reperfusion. At the end of the reperfusion, animals were euthanized, and hearts were harvested for histological and biochemical examination.Results:The levels of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) were higher in Groups I and III than those in Group II (p < 0.05). In comparison with other groups, tissue malondialdehyde (MDA) levels in Group II were significantly increased (p < 0.05), and this increase was prevented by tramadol. Histopathological changes, including microscopic bleeding, edema, neutrophil infiltration, and necrosis, were scored. The total injuryscore in Group III was significantly decreased (p < 0.05) compared with Group II.Conclusion:From the histological and biochemical perspectives, treatment with tramadol alleviated the myocardial injuries induced by skeletal muscle IR in this experimental model.

ResumoFundamento:Lesões a órgãos ocorrem não apenas durante períodos de isquemia, mas paradoxalmente, também durante a reperfusão. Sabe-se que a reperfusão pós-isquêmica (RPI) causa lesões tanto remotas quanto locais no órgão afetado.Objetivo:Este estudo avaliou os efeitos do tramadol no coração como órgão remoto, após RPI aguda dos membros posteriores.Métodos:Trinta ratos Wistar, machos, adultos e saudáveis, foram distribuídos aleatoriamente em três grupos: Grupo I (controle), Grupo II (RPI) e Grupo III (RPI + tramadol). Isquemia foi induzida em ratos anestesiados através do pinçamento da artéria femoral esquerda por 3 horas, seguidas de 3 horas de reperfusão. Tramadol foi administrado (20 mg/kg, IV) imediatamente antes da reperfusão. Ao final da reperfusão, os animais foram sacrificados e seus corações coletados para exames histológicos e bioquímicos.Resultados:Os níveis de superóxido-dismutase (SOD), catalase (CAT) e glutationa-peroxidase (GPx) foram maiores nos grupos I e III que no grupo II (p < 0.05). Em comparação aos outros grupos, os níveis tissulares de malondialdeído (MDA) estavam significativamente mais elevados no grupo II (p < 0.05), o que foi evitado pelo uso de tramadol. Foram pontuadas as alterações histopatológicas, incluindo micro-hemorragia, edema, infiltração por neutrófilos e necrose. A pontuação total das lesões do grupo III foi significativamente menor (p < 0.05) em comparação ao grupo II.Conclusão:Do ponto de vista histológico e bioquímico, o tratamento com tramadol diminuiu as lesões miocárdicas induzidas pela RPI da musculatura esquelética neste modelo experimental.

Beneficial effect of pentoxifylline into the testis of rats in an experimental model of unilateral hindlimb ischemia/reperfusion injury

The objective of the present study was to investigate the role of pentoxifylline (PTX) on remote testicular injury caused by unilateral hind limb ischemia/reperfusion of rats.

Otostegia persica extraction on healing process of burn wounds

PURPOSE: To investigate if the methanolic extract of the Otostegia persica can accelerating healing process of burn wound because of its anti-inflammatory and antioxidant effects. METHODS:Forty eight male Wistar rats were randomized into three study groups of 16 rats each. Burn wounds were created on dorsal part of shaved rats using a metal rod. In group I the burn wound was left without any treatment. Group was treated with topical silver sulfadiazine pomade. In group III, ointment containing the OP extract was administered. Skin biopsies were harvested from burn area on the 3rd, 5th, 14th and 21st days after burn and examined histologically. RESULTS: Re-epithelialization in the control group and in group II was lower than in group III. Re-epithelialization in groups II and III was significantly different from that in the control group. On the 5th day of the experiment, we assessed lower inflammation in the burn area compared to control group. This means that the inflammation was suppressed by methanolic extract of OP. From day 5 to 14; the fibroblast proliferation peaked and was associated with increased collagen accumulation. It was obvious that angiogenesis improved more in the groups II and III, which facilitated re-epithelialisation. CONCLUSION:Methanolic extract of Otostegia persica exhibited significant healing activity when topically applied on rats. OP is an effective treatment for saving the burn site.

Effect of tramadol on lung injury induced by skeletal muscle ischemia-reperfusion: an experimental study / Efeito do tramadol na lesao pulmonar induzida por isquemia-reperfusao de musculo esqueletico: um estudo experimental

OBJECTIVE: To determine whether tramadol has a protective effect against lung injury induced by skeletal muscle ischemia-reperfusion. METHODS: Twenty Wistar male rats were allocated to one of two groups: ischemia-reperfusion (IR) and ischemia-reperfusion + tramadol (IR+T). The animals were anesthetized with intramuscular injections of ketamine and xylazine (50 mg/kg and 10 mg/kg, respectively). All of the animals underwent 2-h ischemia by occlusion of the femoral artery and 24-h reperfusion. Prior to the occlusion of the femoral artery, 250 IU heparin were administered via the jugular vein in order to prevent clotting. The rats in the IR+T group were treated with tramadol (20 mg/kg i.v.) immediately before reperfusion. After the reperfusion period, the animals were euthanized with pentobarbital (300 mg/kg i.p.), the lungs were carefully removed, and specimens were properly prepared for histopathological and biochemical studies. RESULTS: Myeloperoxidase activity and nitric oxide levels were significantly higher in the IR group than in the IR+T group (p = 0.001 for both). Histological abnormalities, such as intra-alveolar edema, intra-alveolar hemorrhage, and neutrophil infiltration, were significantly more common in the IR group than in the IR+T group. CONCLUSIONS: On the basis of our histological and biochemical findings, we conclude that tramadol prevents lung tissue injury after skeletal muscle ischemia-reperfusion. .

OBJETIVO: Investigar se o tramadol tem um efeito protetor contra a lesão pulmonar induzida por isquemia-reperfusão de músculo esquelético. MÉTODOS: Vinte ratos Wistar machos foram divididos em dois grupos: grupo isquemia-reperfusão (IR) e grupo isquemia-reperfusão + tramadol (IR+T). Os animais foram anestesiados com cetamina e xilazina (i.m., 50 mg/kg e 10 mg/kg, respectivamente). Todos os animais foram submetidos a 2 h de isquemia por oclusão da artéria femoral e 24 h de reperfusão. Antes da oclusão da artéria femoral, foram administrados 250 UI de heparina pela veia jugular para impedir a coagulação. Os ratos do grupo IR+T foram tratados com tramadol (20 mg/kg i.v.) imediatamente antes da reperfusão. Após o período de reperfusão, os animais foram sacrificados com pentobarbital (300 mg/kg i.p.), os pulmões foram removidos cuidadosamente, e os espécimes foram preparados adequadamente para estudos histopatológicos e bioquímicos. RESULTADOS: A atividade de mieloperoxidase e os níveis de óxido nítrico foram significativamente maiores no grupo IR que no grupo IR+T (p = 0,001 para ambos). Anormalidades histológicas, como edema intra-alveolar, hemorragia intra-alveolar e infiltração neutrofílica, foram significativamente mais frequentes no grupo IR que no grupo IR+T. CONCLUSÕES: Com base nos resultados histológicos e bioquímicos ...

Study on nano-structured hydroxyapatite/zirconia stabilized yttria on healing of articular cartilage defect in rabbit

PURPOSE: Articular Cartilage has limited potential for self-repair and tissue engineering approaches attempt to repair articular cartilage by scaffolds. We hypothesized that the combined hydroxyapatite and zirconia stabilized yttria would enhance the quality of cartilage healing. METHODS: In ten New Zealand white rabbits bilateral full-thickness osteochondral defect, 4 mm in diameter and 3 mm depth, was created on the articular cartilage of the patellar groove of the distal femur. In group I the scaffold was implanted into the right stifle and the same defect was created in the left stifle without any transplant (group II). Specimens were harvested at 12 weeks after implantation, examined histologically for morphologic features, and stained immunohistochemically for type-II collagen. RESULTS: In group I the defect was filled with a white translucent cartilage tissue In contrast, the defects in the group II remained almost empty. In the group I, the defects were mostly filled with hyaline-like cartilage evidenced but defects in group II were filled with fibrous tissue with surface irregularities. Positive immunohistochemical staining of type-II collagen was observed in group I and it was absent in the control group. CONCLUSION: The hydroxyapatite/yttria stabilized zirconia scaffold would be an effective scaffold for cartilage tissue engineering.

Combination of poly L-lactic acid nanofiber scaffold with omentum graft for bone healing in experimental defect in tibia of rabbits / Combinação de poli L-ácido láctico nanofibras com enxerto de omento para reparo ósseo em defeito experimental em tíbia de coelhos

PURPOSE: To investigate the osteoconductive properties and biological performance of Poly L-lactic acid (PLLA) with omentum in bone defects. METHODS: PLLA nanofiber scaffolds were prepared via electrospinning technique. Forty four New Zealand white female rabbits randomly divided into three groups of 18 rabbits each. Created defects in right tibias were filled in group I with omentum, in group II with PLLA nanofiber scaffold and in group III with combination of the omentum and PLLA. The same defects were created in left tibia of all groups but did not receive any treatment (control group). Histological and histomorphometric evaluations were performed at two, four and six weeks after the implantation. RESULTS: Histological changes on all groups along with the time course were scored and statistical analysis showed that the average scores in group III were significantly higher than the other groups. CONCLUSION: Histomorphometric analysis of bone healing was shown to be significantly improved by the combined PLLA with omentum compared with the other groups, suggesting this biomaterial promote the healing of cortical bone, presumably by acting as an osteoconductive scaffold.

OBJETIVO: Investigar as propriedades de osteocondução e desempenho biológico do ácido L láctico-Poly (PLLA) com omento em defeitos ósseos. MÉTODOS: Andaimes PLLA nanofibras foram preparados via eletrofiação técnica. Cinquenta e quatro coelhos fêmeas Nova Zelândia brancos foram distribuídos aleatoriamente em três grupos de 18 coelhos cada. Defeitos criados em tíbias direitas foram preenchidos no grupo I com omento, no grupo II com PLLA nanofibras e no grupo III com a combinação do omento e PLLA. Os mesmos defeitos foram criados na tíbia esquerda de todos os grupos, mas não receberam qualquer tratamento (grupo controle). As avaliações histológicas e histomorfométricas foram realizadas em duas, quatro e seis semanas após a implantação. RESULTADOS: As alterações histológicas em todos os grupos, juntamente com o curso de tempo foram marcados e análise estatística mostrou que as pontuações médias do grupo III foram significativamente mais elevadas do que os outros grupos. CONCLUSÃO: Análise histomorfométrica da cicatrização óssea mostrou-se significativamente melhor com o PLLA combinado com omento em comparação com os outros grupos, sugerindo que este biomaterial promove a cicatrização do osso cortical, provavelmente atuando como osteocondutor.

Protective effect of N-acetylcysteine on kidney as a remote organ after skeletal muscle ischemia-reperfusion / Efeito protetor da N-acetilcisteína no rim como um órgão remoto músculo esquelético após isquemia-reperfusão

PURPOSE: To investigate whether N-acetylcysteine has a protective effect against renal injury as a remote organ after skeletal muscle ischemia-reperfusion in rats. METHODS: Twenty Wistar male rats were divided randomly into two experimental groups: group ischemia-reperfusion (group I) and group ischemia-reperfusion + N-acetylcysteine (group II). After ketamine and xylazine anesthesia, femoral artery was exposed. All animals were undergone 2h of ischemia by occlusion femoral artery and 24h of reperfusion. Rats that were treated with N-acetylcysteine given IV at a dose of 150 mg/kg-¹, immediately before reperfusion. After 24h of reperfusion, the blood samples were collected and submitted for evaluation of plasmatic urea, creatinine values and then rats were euthanized and left kidney harvested for histopathological analysis under light microscopy. RESULTS: The urea (35±7.84 mg.dL-1), creatinine (1.46±0.47 mg.dL-1) values were significantly lower in group II (P=0.000). Renal histopathologic study in group I showed extensive distal and proximal tubular cells necrosis and sloughing of epithelial cells into the tubular lumen, cast formation in tubule and glomerul, glomerul fibrosis and hemorrhage. Histopathologically, there was a significant difference (p=0.037) between two groups. CONCLUSION: The N-acetylcysteine was able to decrease renal injury induced by skeletal muscle ischemia reperfusion in rats.

OBJETIVO: Investigar se a N-acetilcisteína tem um efeito protetor contra a lesão renal como um órgão remoto músculo esquelético após isquemia-reperfusão em ratos. MÉTODOS: Vinte ratos Wistar machos foram distribuídos aleatoriamente em dois grupos experimentais: grupo isquemia-reperfusão (grupo I) e grupo isquemia-reperfusão N-acetilcisteína (grupo II). Após a anestesia de ketamina e xilazina, a artéria femoral foi exposta. Todos os animais foram submetidos a 2h de isquemia pela oclusão da artéria femoral e 24h de reperfusão. Os ratos que foram tratados com N-acetilcisteína administrados IV na dose de 150 mgkg-1, imediatamente antes da reperfusão. Após 24h de reperfusão, as amostras de sangue foram coletadas e submetidas para avaliação de uréia, creatinina e, em seguida, os ratos foram sacrificados e rim esquerdo retirados para estudo histopatológico em microscopia de luz. RESULTADOS: A uréia (35 ± 7,84 mg.dL-1), creatinina (1,46 ± 0,47 mg.dL-1) os valores foram significativamente menores no grupo II (p=0,000). Estudo histopatológico renal do grupo I mostrou extensa necrose distal e proximal, células tubular e descamação das células epiteliais para o lúmen tubular, formação de elenco no túbulo e glomerulo, fibrose glomerular e hemorragia. Histopatologicamente houve uma diferença significativa (p=0,037) entre os dois grupos. CONCLUSÃO: A N-acetilcisteína foi capaz de diminuir a lesão renal induzida por reperfusão de isquemia do músculo esquelético em ratos.

Effect of N-acetylcysteine on lung injury induced by skeletal muscle ischemia-reperfusion: histopathlogical study in rat model / Efeito de N-acetilcisteína em dano pulmonar induzido por isquemia-reperfusão de músculo esquelético: estudo histopatólogico em modelo de rato

PURPOSE: To investigate whether N-acetylcysteine, a free radicals scavenger has a protective effect against lung injury as a remote organ after skeletal muscle ischemia-reperfusion. METHODS: Twenty Wistar male rats were divided randomly into two experimental groups: group ischemia-reperfusion (group I) and group ischemia-reperfusion + N-acetylcysteine (group II). All animals were undergone two hours of ischemia by occlusion femoral artery and 24h of reperfusion. Before clamped the femoral artery, 250 IU heparin was administered via the jugular vein to prevent clotting. Rats that were treated with N-acetylcysteine given IV at a dose of 150 mgkg-¹, immediately before reperfusion. After 24h of reperfusion, animals were euthanized and left lung harvested for histopathological analysis under light microscopy. RESULTS: In the group I, tissues showed histological changes with intra-alveolar edema, intra-alveolar hemorrhage and neutrophilic infiltration. Histopathologically, there was a significant difference (P = 0.005) between two groups. CONCLUSION: Administration of N-acetylcysteine treatment significantly decreased lung injury induced by skeletal muscle ischemia reperfusion according to histological findings.

OBJETIVO: Investigar se N-acetilcisteína, neutralizador de radicais livres, tem efeito protetor contra dano pulmonar como um órgão remoto após isquemia-reperfusão de músculo esquelético. MÉTODOS: Vinte ratos machos Wistar, foram aleatóriamente distribuídos em dois grupos: grupo isquemia-reperfusão (grupo I) e grupo isquemia-reperfusão +N-acetilcisteína (grupo II). Todos os animais foram submetidos a duas horas de ischemia pela oclusão artéria femoral e 24 horas de reperfusão. Antes de ocluir a artéria femoral, foi administrado 250 IU de heparina pela veia jugular para prevenir coagulação. A N-acetilcisteína foi administrada por via intravenosa, na uma dose de 150 mgkg-1, imediatamente antes de reperfusão. Após 24 horas de reperfusão, os animais foram eutanasiados e o pulmão esquerdo foi removido para análise histológica em microscopia óptica. RESULTADOS: No grupo I, os tecidos mostraram alterações histológicas com edema e hemorragia intra-alveolar e infiltração neutrofílica. Houve diferença histopatológica significante (P = 0.005) entre os dois grupos. CONCLUSÃO: O tratamento com a N-acetilcisteína diminuiu significantemente o dano pulmonar induzido por isquemia-reperfusão de músculo esquelético.