The effects of melatonin on burn-induced inflammatory responses and coagulation disorders in rats.

The aim of this study was to investigate the effects of melatonin on burn-induced inflammatory responses and coagulation disorders in a rat model. Under ether anesthesia, shaved dorsa of rats were exposed to 90 degrees C for 10 s to induce burn injury. Melatonin (10 mg/kg) was administered immediately and after 12 h. Standard coagulation tests (prothrombin activity [PA] and activated partial thromboplastin time [aPTT]), platelet number and morphology; proinflammatory markers (C-reactive protein [CRP] and fibrinogen) and lipid peroxidation marker (malondialdehyde [MDA]) levels were assayed. Thermal injury increased the levels of MDA (by 76%, P < 0.0001), CRP (by 33%, P < 0.0001), fibrinogen (4.5-fold, P < 0.0001) and PA (by 37%; P < 0.01). Changes in aPTT and platelet numbers were nonsignificant. Melatonin diminished the elevated CRP and fibrinogen levels, normalized MDA levels, platelet morphology and decreased PA. A positive association of MDA with fibrinogen and MDA with PA were noted after melatonin treatment. To conclude, melatonin as an antioxidant and anti-inflammatory agent exerted a suppressive effect on burn-induced disorders in blood coagulation and might be useful in the prevention of disseminated intravascular microthrombosis.

Protective effect of melatonin against oxidative hepatic injury after experimental thermal trauma.

Burns cause thermal injury to local tissue, trigger systemic inflammatory processes and activate lipid peroxidation, leading to multiple distant organ injury. Melatonin is a lipid- and water-soluble antioxidant and membrane stabilizer with antiinflammatory, hepatoprotective and gastroptotective properties, among others. We studied the influence of melatonin on hepatic damage induced by thermal skin injury and its possible relation to hepatic lipid peroxidative status and systemic inflammatory response. Under ether anesthesia the shaved dorsum of rats was exposed to a 90 degrees C bath for 10 s. Melatonin was administered intraperitoneally immediately after burns. Malondialdehyde (MDA), aspartate transaminase (AST) and alanine transaminase (ALT) were determined in liver and blood plasma and used as markers of oxidative status. Plasma C-reactive protein (CRP) was used as a marker of systemic inflammatory response. Thermal skin injury caused significant elevation of hepatic MDA by 48%, plasma CRP levels by 30% and plasma AST and ALT activities by 2- and 3.5-fold, respectively, in comparison with normal control rats. Treatment with melatonin (10 mg/kg) significantly inhibited the elevation in hepatic MDA and plasma CRP levels, reaching control values at 24 h. Melatonin treatment restricts the elevation of plasma AST and ALT activities (P < 0.001), which remain significantly increased as compared with controls. In conclusion, the protective effect of melatonin is likely to be due to attenuated lipid peroxidation and interference with reduced oxidative stress and inflammatory response, as evidenced by decreased hepatic MDA and plasma CRP levels.

Hypoglycemic and hypolipidemic effects of Aronia melanocarpa fruit juice in streptozotocin-induced diabetic rats.

Aronia melanocarpa fruit juice (AMFJ) is rich in phenolic antioxidants, especially flavonoids from the anthocyanin subclass. The aim of the present study was to investigate the influence of AMFJ on plasma glucose and lipids in diabetic rats. Diabetes was induced by an intraperitoneal injection of streptozotocin (50 mg/kg). AMFJ was applied by gavage at doses of 10 and 20 ml/kg for 6 weeks to normal and diabetic rats. Streptozotocin caused a significant elevation of plasma glucose by 141% and of plasma triglycerides (TG) by 64% in comparison with normal control rats and induced statistically insignificant elevations of total cholesterol and LDL-cholesterol and a reduction of HDL-cholesterol. Applied to normal rats, AMFJ did not influence plasma glucose and lipid levels. Applied to diabetic rats, AMFJ (10 and 20 ml/kg) significantly reduced plasma glucose by 44% and 42% and TG by 35% and 39%, respectively, to levels that did not significantly differ from those of the normal control rats and counteracted the influence of streptozotocin on total cholesterol, LDL-cholesterol and HDL-cholesterol. In conclusion, AMFJ significantly decreased the streptozotocin-induced abnormalities in blood glucose and TG in diabetic rats and might be useful in prevention and control of diabetes mellitus and diabetes-associated complications.