Melatonin protects female rats against steatosis and liver oxidative stress induced by oestrogen deficiency.
OBJECTIVE
Melatonin has been shown to protect cells against oxidative and inflammatory damage via endocrine, paracrine and autocrine actions. Postmenopausal condition is associated with a high incidence of many features of metabolic syndrome including obesity, steatosis and liver oxidative injuries. The aim of this work was to investigate whether treatment with melatonin improves metabolic disturbances associated with oestrogen deficiency in ovariectomised (OVX) rats.


METHODS
OVX and control (CON) female rats were treated with melatonin (10mg/kg×day for 3weeks, p.o.). Body weight gain, adiposity index, plasma biochemical parameters, liver lipid content, hepatic mitochondrial respiration, fatty acid oxidation and mitochondrial H2O2 generation and the activity of the most important enzymatic and non-enzymatic reactive oxygen species (ROS) scavenger systems were measured.


RESULTS
In OVX rats, melatonin suppressed lipid accumulation and cellular oxidative stress in the liver. There was a reduction in the levels of carbonylated proteins in the mitochondria and cytosol, reduction in the malondialdehyde contents in the liver homogenates, stimulation of cytosolic glutathione peroxidase and glutathione reductase activities and restoration of reduced glutathione contents to normal levels.


CONCLUSIONS
Exogenous melatonin protects the liver of OVX rats against steatosis and cellular oxidative stress, possibly via activation of antioxidant enzymes related to glutathione metabolism and by a direct radical scavenging activity.
Department of Biochemistry, Laboratory of Biological Oxidations, Universidade of Maringá, Maringá 87020900, Brazil; Department of Biochemistry, Laboratory of Experimental Steatosis, Universidade of Maringá, Maringá 87020900, Brazil.
Danielle Aparecida Munhos
DAM
Hermoso
Department of Biochemistry, Laboratory of Biological Oxidations, Universidade of Maringá, Maringá 87020900, Brazil; Centro Educacional Integrado, Campo Mourão 87300970, Brazil; Department of Biochemistry, Laboratory of Experimental Steatosis, Universidade of Maringá, Maringá 87020900, Brazil.
Lilian Brites Campos
LBC
Shimada
Department of Biochemistry, Laboratory of Biological Oxidations, Universidade of Maringá, Maringá 87020900, Brazil; Department of Biochemistry, Laboratory of Experimental Steatosis, Universidade of Maringá, Maringá 87020900, Brazil.
Eduardo Hideo
EH
Gilglioni
Department of Biochemistry, Laboratory of Biological Oxidations, Universidade of Maringá, Maringá 87020900, Brazil; Department of Biochemistry, Laboratory of Experimental Steatosis, Universidade of Maringá, Maringá 87020900, Brazil.
Jorgete
J
Constantin
Department of Biochemistry, Laboratory of Biological Oxidations, Universidade of Maringá, Maringá 87020900, Brazil; Department of Biochemistry, Laboratory of Experimental Steatosis, Universidade of Maringá, Maringá 87020900, Brazil.
Márcio Shigueaki
MS
Mito
Department of Biochemistry, Laboratory of Biological Oxidations, Universidade of Maringá, Maringá 87020900, Brazil; Department of Biochemistry, Laboratory of Experimental Steatosis, Universidade of Maringá, Maringá 87020900, Brazil.
Aparecida Pinto Munhos
APM
Hermoso
Department of Physiological Sciences, University of Maringá, Maringá 87020900, Brazil.
Clairce Luzia
CL
Salgueiro-Pagadigorria
Department of Biochemistry, Laboratory of Biological Oxidations, Universidade of Maringá, Maringá 87020900, Brazil; Department of Biochemistry, Laboratory of Experimental Steatosis, Universidade of Maringá, Maringá 87020900, Brazil. Electronic address: eliiwamoto@uem.br.
Emy Luiza Ishii
ELI
Iwamoto
D000818:Animals; D004967:Estrogens / Q000172:deficiency*; D005227:Fatty Acids / Q000378:metabolism; D005234:Fatty Liver / Q000517:prevention & control*; D005260:Female; D008055:Lipids / Q000097:blood; D008099:Liver / Q000187:drug effects*; D008550:Melatonin / Q000494:pharmacology*; D008930:Mitochondria, Liver / Q000378:metabolism; D010084:Oxidation-Reduction; D018384:Oxidative Stress / Q000187:drug effects*; D051381:Rats; D017208:Rats, Wistar
D004967:Estrogens; D005227:Fatty Acids; D008055:Lipids; D008550:Melatonin
Melatonin; Obesity; Ovariectomy; Steatosis