Long-term effects of melatonin and resveratrol on aging rats: A multi-biomarker approach.

Aging-related impaired body structure and functions may be, at least partially, caused by elevated oxidative stress. Melatonin (MEL) and resveratrol (RSV) may act as antioxidant and anti-aging compounds, but these actions in experimental animals and humans are controversial. Herein, a rat model of aging was used to study the long-term sex-related effects of MEL and RSV treatment on body mass and blood/plasma parameters of DNA damage, oxidative status (glutathione and malondialdehyde levels), and concentrations of sex hormones. Starting from the age of 3mo, for the next 9mo or 21mo male and female Wistar rats (n = 4-7 per group) were given water to drink (controls) or 0.1 % ethanol in water (vehicle), or MEL or RSV (each 10 mg/L vehicle). DNA damage in whole blood cells was tested by comet assay, whereas in plasma, glutathione, malondialdehyde, and sex hormones were determined by established methods. Using statistical analysis of data by ANOVA/Scheffe post hoc, we observed a similar sex- and aging-dependent rise of body mass in both sexes and drop of plasma testosterone in control and vehicle-treated male rats, whose pattern remained unaffected by MEL and RSV treatment. Compared with controls, all other parameters remained largely unchanged in aging and differently treated male and female rats. We concluded that the sex- and aging-related pattern of growth and various blood parameters in rats were not affected by the long-term treatment with MEL and RSV at the estimated daily doses (300-400 µg/kg b.m.) that exceed usual moderate consumption in humans.

Resveratrol as antioxidant in cardiac surgery: is there potential for clinical application?

Cardiopulmonary bypass (CPB) is an essential technique in cardiac surgery but is also associated with adverse effects, including the systemic inflammatory response syndrome that manifests itself as ischaemia-reperfusion injury and multi-organ dysfunction. The aim of this mini review is to take a look at the current knowledge of resveratrol, a stilbenoid and natural antioxidant believed to have many cardioprotective effects including vasodilation, lowering of blood pressure and reactive oxygen species levels, suppression of low-density lipoprotein peroxidation, and mitigation of ischaemia/-reperfusion injury. We mostly focus on its cardioprotective potential in patients undergoing cardiac surgery supported by CPB. Current findings, however, are still inconclusive and call for further research, including clinical trials.

Sex-dependent expression of metallothioneins MT1 and MT2 and concentrations of trace elements in rat liver and kidney tissues: Effect of gonadectomy.

Metallothioneins (MTs) exhibit binding affinity for several essential and toxic trace elements. Previous studies in rodents indicated sex differences in the hepatic and renal expression of MTs and concentrations of various elements. The mechanism responsible for these differences has not been resolved. Here, in the liver and kidney tissues of sham-operated and gonadectomized male and female rats we determined the expression of MT1 and MT2 (MT1&2) mRNA by RT-PCR, abundance of MT1&2 proteins by Western blotting and immunocytochemistry, concentrations of essential (Fe, Zn, Cu, Co) and toxic (Cd, Hg, Pb) elements by ICP-MS, and oxidative status parameters (SOD, GPx, MDA, GSH) by biochemical methods. In both organs, the expression of MT1&2 mRNA and MT1&2 proteins was female-dominant, upregulated by castration, and downregulated by ovariectomy. Concentrations of Fe in the liver and Co in the kidneys followed the same pattern. Most other elements (Zn, Cu, Cd, Hg) exhibited female- or male-dominant sex differences, affected by gonadectomy in one or both organs. Pb was sex- and gonadectomy-unaffected. GPx and MDA were elevated and associated with the highest concentrations of Fe only in the female liver. We conclude that the sex-dependent expression of MT1&2 mRNA and proteins in the rat liver and kidneys may include different mechanisms. In the liver, the female-dominant tissue concentrations of Fe may generate oxidative stress which is a potent enhancer of MTs production, whereas in kidneys, the female-dominant expression of MTs may be unrelated to Fe-mediated oxidative stress.