Changes in the tissue and plasma superoxide dismutase (SOD) levels in a burned rat model

Effect of melatonin on the gastric antioxidant defence in experimental burn trauma

Severe burn trauma triggers oxidative gastric mucosal injury. The purpose of this study was to investigate the antioxidant defence mechanisms and protective effect of melatonin in the gastric mucosa after burn injury. In order to investigate the mechanisms involved in the gastric antioxidant defence in a rat burn model, quantitative real-time PCR and immunohistochemistry techniques were applied. An analysis of glutathione peroxidase 4 (GPx4), glutathione reductase (GR), and catalase (Cat) gene expression was performed along with the evaluation of the gastric Cu/Zn superoxide dismutase (Cu/Zn SOD) activity. Melatonin was applied immediately and 12 h after 30% of total body surface area burns. The burn injury significantly increased the Gpx4 mRNA (P < 0.000 1) and Gsr mRNA (P < 0.000 1) expression. It also had a slight positive effect on the Cat mRNA expression and Cu/Zn SOD activity. Melatonin, in turn, markedly augmented the burn-induced Cu/Zn SOD (P < 0.000 1) activity, reversed the Gpx4 mRNA (P < 0.000 1) and Gsr mRNA (P < 0.000 1) expression, and inhibited the Cat mRNA level. In conclusion, the present study suggests that a burn injury adaptively increases the Cu/Zn SOD activity and enhances the Gpx4 and Gsr gene expression in the gastric mucosa. Melatonin effectively modulates the expression of the cellular antioxidant enzymes, and improves the antioxidant defence by augmenting the Cu/Zn SOD activity.

Evaluation of plasma oxidative stress, with or without antioxidant supplementation, in superficial partial thickness burn patients: a pilot study

BACKGROUND

Oxidative stress is one of the main causes of pathophysiological alterations observed during burn injury. The present pilot study aimed to determine whether a specific oral antioxidant supplementation could in any way influence free radical blood values in patients affected by superficial partial thickness burns.

MATERIALS AND METHODS

Plasma oxidants and plasma antioxidant capacity were analysed in 20 superficial partial thickness burn patients for a 2-week period; patients were randomly divided into two groups, one of which was supported with a specifically designed oral antioxidant formula (Squalene 100 mg, Vitamin C 30 mg, Coenzyme Q10 10 mg, Zinc 5 mg, Beta Carotene 3.6 mg, Bioflavonoids 30 mg, Selenium 55 mcg) administered daily, starting from the day of admission, for the whole study period.

RESULTS

No significant differences were found in plasma oxidants and plasma antioxidant capacity between the two groups of patients.

CONCLUSIONS

These results did not reflect any significant benefits of an antioxidant oral supplementation at usual dosages when considering oxidative plasmatic values of superficial partial thickness burn patients.

Targeting the redox balance in inflammatory skin conditions

Reactive oxygen species (ROS) can be both beneficial and deleterious. Under normal physiological conditions, ROS production is tightly regulated, and ROS participate in both pathogen defense and cellular signaling. However, insufficient ROS detoxification or ROS overproduction generates oxidative stress, resulting in cellular damage. Oxidative stress has been linked to various inflammatory diseases. Inflammation is an essential response in the protection against injurious insults and thus important at the onset of wound healing. However, hampered resolution of inflammation can result in a chronic, exaggerated response with additional tissue damage. In the pathogenesis of several inflammatory skin conditions, e.g., sunburn and psoriasis, inflammatory-mediated tissue damage is central. The prolonged release of excess ROS in the skin can aggravate inflammatory injury and promote chronic inflammation. The cellular redox balance is therefore tightly regulated by several (enzymatic) antioxidants and pro-oxidants; however, in case of chronic inflammation, the antioxidant system may be depleted, and prolonged oxidative stress occurs. Due to the central role of ROS in inflammatory pathologies, restoring the redox balance forms an innovative therapeutic target in the development of new strategies for treating inflammatory skin conditions. Nevertheless, the clinical use of antioxidant-related therapies is still in its infancy.

Markers of oxidative stress after ablation of atrial fibrillation are associated with inflammation, delivered radiofrequency energy and early recurrence of atrial fibrillation

BACKGROUND

The role of oxidative stress after radiofrequency ablation of atrial fibrillation (AF) has not yet been well characterized. We sought to evaluate the time course of biomarkers of oxidative stress and inflammation after AF ablation and their association with clinical variables.

METHODS

Thirty consecutive patients (57.9 ± 1.7 years, 63% males) with paroxysmal AF underwent pulmonary vein isolation and ablation of complex fractionated atrial electrograms. Biomarkers were determined in blood samples before ablation and 6 h, 1, 2, 7, 30, 90 and 180 days post-ablation.

RESULTS

The pro-oxidant enzyme myeloperoxidase and oxidized low-density lipoprotein reflecting oxidant damage of lipoproteins increased 2.9 ± 0.2-fold and 1.2 ± 0.1-fold, respectively, and were significantly up-regulated until day 2 post-ablation. The anti-oxidant enzyme copper/zinc superoxide dismutase did not change significantly. Inflammatory markers significantly increased (high-sensitivity C-reactive protein (hs-CRP): 41 ± 8-fold; interleukin-6: 4.4 ± 0.7-fold) for 7 and 2 days, respectively. The increase of myeloperoxidase and hs-CRP was interrelated and both predicted early recurrence of AF within the first post-ablation week (both p < 0.05). The increase of both markers was associated with the amount of delivered radiofrequency energy (p < 0.05). The up-regulation of hs-CRP correlated with troponin T (p = 0.008), while myeloperoxidase and troponin T were borderline associated (p = 0.054). However, the oxidative and inflammatory responses did not predict long-term ablation outcome (p > 0.05).

CONCLUSIONS

Markers of oxidative stress showed a significant up-regulation during the first 2 days after AF ablation. Their up-regulation was linked to inflammation, delivered radiofrequency energy, and early recurrence of AF, but did not predict long-term ablation outcome.

Caffeic Acid Phenethyl Ester Improves Oxidative Erythrocyte Damage in a Rat Model of Thermal Injury

Oxygen-derived free radicals impair cell membrane functions and induce circulatory disturbances, and free radicals, such as superoxide anion, hydrogen peroxide, hydroxyl radicals, and peroxynitrite, have been suggested to play important roles in the pathogenesis of major burn injuries. The present study investigated the effects of thermal injury on erythrocyte lipid peroxidation and antioxidant status and investigated the effects of caffeic acid phenethyl ester (CAPE), a new antioxidant and anti-inflammatory agent, in rats subjected to thermal injury. Burn injury caused a remarkable increase in erythrocyte lipid peroxidation, levels of nitric oxide (NO), and activities of antioxidant enzymes and xanthine oxidase (XO). The treatment with CAPE decreased both activity of burn-induced XO activity and levels of NO in the erythrocytes. In conclusion, CAPE treatment resulted in decreased erythrocyte lipid peroxidation in thermal injury and helped to prevent oxidative damage by decreasing activity of XO and levels of NO.

Dissociation between gene expression and protein contents of tissue superoxide dismutase in a rat model of lethal burns

The aim of this study was to examine the changes in the tissue Cu/Zn- and the Mn-SOD contents and gene expression following mild and severe burns in a rodent burn model. Thirty-eight male Wistar rats, weighing 208-278g, were divided into a sham burn group and two burn groups, with one receiving burns to 35% of the body surface and the other to 60%. Twenty animals of the burn groups were monitored daily for 7 days after injuries to examine survival. Six animals in the sham, 35 or 60% burn group were sacrificed at 3h postburn, and the blood, lungs and kidneys were collected for a biological analysis. The Cu/Zn- and Mn-SOD contents of the tissue and plasma specimens were measured using ELISA. The mRNA expressions of Cu/Zn- and Mn-SOD were determined by a Northern blot analysis. The survival rate of the 60% burn group for 7 days was 30%, whereas the survival rate of the 35% burn group was 100%. The mRNA expressions of Mn-SODs in the lung and the kidney were significantly higher in the 60% burn group than in 35% burn or sham burn group, as was the mRNA expression of lung Cu/Zn-SOD. Nevertheless, the tissue SOD contents in the 60% burn group (mortality 70%) did not exceed those in the 35% group. Based on these findings, tissue SOD synthesis is thus suggested to be inhibited in lethal burns in spite of a strong mRNA expression of SOD.