Effects of melatonin on low-dose lipopolysaccharide-induced oxidative stress in mouse liver, muscle, and kidney.

Lipopolysaccharide (LPS) administration in an in vivo experimental mice model causes oxidative damage in the liver, muscle, and kidney. We aimed to determine specific mechanisms underlying melatonin's antioxidant protective role. Assays were carried out in quadruplicate in the control, melatonin (10 mg/kg, 10 days), acute LPS administration (once 150 μg), and LPS + melatonin groups. LPS stimulated lipid peroxidation processes (dienes and malondialdehyde) and antioxidant enzyme concentrations (superoxide dismutase, catalase, glutathione peroxidase, and glutathione reductase) were assessed in all investigated tissues. Protein oxidation processes (measured as aldehyde and kenotic carbonyl protein derivatives) were enhanced by LPS in the kidney and liver but not in muscle. Melatonin reversed LPS-induced changes, with the exception of muscle protein oxidation. LPS-induced oxidative stress resulted in augmented early-stage diene conjugated and end-stage malondialdehyde lipid peroxidation processes and affected antioxidant activity in liver, kidney, and muscle tissues. LPS activated protein oxidation processes in the kidney and liver. Melatonin ameliorated oxidative damage in the liver, kidney, and partially in the muscle. Melatonin modulates oxidative stress-induced states. Potential synergism between melatonin and systemic inflammation in terms of oxidative modification of muscle proteins needs to be clarified in further studies.