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Aims of this study were to demonstrate influence of contraction type on irisin and metabolome, and reveal the unknown relationships of irisin with metabolites and metabolic pathways. Sixteen healthy male athletes exercised on a dynamometer for 5 to 6 minutes concentrically and isometrically 3-weeks apart in a sports medicine clinic. Independent variables were body composition parameters, handgrip strength, weekly exercise volume, maximal heart rate achieved during the training, and Borg ratings. Dependent variables were plasma irisin and metabolic profiles. ELISA analysed plasma irisin. Untargeted metabolomic profile was assessed by Q-TOF LC/MS instrument. Selected peaks were uploaded to MetaboAnalyst 5.0 software to identify Kyoto Encyclopedia of Genes and Genomes codes. Concentric but not isometric exercise increased plasma irisin and an average of 23% change was observed in the former intervention (P = 0.007). Leg muscle mass and physical activity level in the week before exercise correlated negatively with irisin fold-change (r = −0.543, P < 0.05; r = −0.481, P = 0.059, respectively). Untargeted metabolomics revealed metabolites correlated with irisin. Concentric exercise activated fatty acid elongation and degradation pathways whereas both types of exercise affected arachidonic acid metabolism, steroid hormone biosynthesis, and regulation of lipolysis in adipocytes pathways. Concentric exercise and isometric exercise differ in metabolic response and irisin stimulation. Recent physical activity status may have an impact on the released irisin in response to exercise. Irisin-related metabolites and pathways that will guide future studies have been revealed by non-targeted metabolomics approach for the first time. [ABSTRACT FROM AUTHOR]

Selenium is shown to have beneficial effects on ischaemia-reperfusion ( IR) injury. Our aim was to assess the effects of selenium on IR-induced testicular damage in terms of biochemical and histopathological evaluation. A total of 32 rats were randomised into four groups: control, IR, IR + selenium ( IR + S) and S. Detorsion was applied after 3 h of torsion. Testicular tissue superoxide dismutase ( SOD), glutathione ( GSH), malondialdehyde ( MDA), total antioxidant capacity ( TAC) and DNA fragmentation levels were determined. Testicular tissue samples were examined by histopathological examination and terminal deoxynucleotidyl transferase dUTP nick end-labelling staining. The control, IR and IR + S groups had higher SOD values compared with the S group; SOD levels of the control and IR + S groups were higher than those of the IR group ( P < 0.05). Further, MDA levels of the IR group were higher than those in the other three groups ( P < 0.05). The IR group revealed lower TAC levels than the three groups ( P < 0.05 for all). GSH levels of the IR group were significantly lower than those in the other three groups ( P < 0.05 for all). In contrast, GSH levels of the IR + S group increased compared with those of the S group. The IR group had more DNA fragmentation than the control and S groups ( P < 0.05). It is concluded that selenium possibly reduces oxidative stress and apoptosis caused by testicular IR injury in rats. The testicular protective effect of selenium appears to be mediated through its anti-apoptotic and antioxidative effects. However, selenium does not affect DNA fragmentation. [ABSTRACT FROM AUTHOR]