MAO Inhibitors in Aging: Can They Serve as Protective Agents in Cardiac Tissue Against Oxidative Stress?

Authors: FERHAN KÜLAHÇIOĞLU GİRGİN, MERT ÖZGÖNÜL, GÜLİNNAZ ALPER, GÜLRİZ MENTEŞ, BİLTAN ERSÖZ, ESER YILDIRIM SÖZMEN

Abstract: Biological damage mediated by reactive oxygen species has been increasingly recognized in aging phenomena in recent decades. The increase in catecholamine metabolism is yet another physiological change in aging, predisposing the organism to supranormal hydrogen peroxide produc-tion as a by-product. This study was undertaken to investigate the alterations in oxidant- antioxidant status in rat cardiac tissue during aging. The effects of acute administration of monoamine oxidase (MAO) inhibitors on this status were also investigated to find possible preventive strategies in conjugate aging. MAO activities, malondialdehyde MDA and diene conjugate levels as well as superoxide dismutase and catalase activities were determined in the cardiac tissues of young and aging groups, each consisting of 10 rats. MAO inhibitors (deprenyl and pargy-line) were administered to another two groups of young and aging animals (10 in each group) and the same parameters were also determined in these groups. Cardiac tissue MAO activities (p<0.005) as well as diene conjugates (p<0.0001) and MDA levels (p<0.005) were found to be significantly higher in aging compared to young control groups. The increases in these parameters were all correlated. Acute MAO inhibitor administration caused significant decreases in MAO activities in both young (p<0.0005 with deprenyl and p<0.0001 with pargyline) and aging groups (p<0.0001 with deprenyl and p<0.00001 with pargyline). Parallel to this finding, diene conjugate and MDA levels were also found to be decreased after MAO administration. Although the aging control group had manifested a decrease in antioxidant enzymes; SOD and catalase (p<0.05, both), acute administration of MAO inhibitors did not induce any significant changes in these parameters. In conclusion, our experimental data suggest that catecholamine metabolism and MAO activity may play a role in the pathological alterations in the aging cardiac tissue by serving as an important source for increased lipid peroxidation, and inhibition of this activity may play a role in limiting the clinical sequelae of these alterations.

Keywords: Monoamine oxidase inhibitors, lipid peroxidation, antioxidant enzymes, cardiac tissue, aging.

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