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.