Abstract:Selenium enhances the cellular antioxidant capacity and alleviates oxidative stress. We investigated the transcriptional and enzymatic activities of selenium-dependent glutathione peroxidase 1 and thioredoxin reductase 1 (TrxR1), and levels of glutathione, hydrogen peroxide, lipid peroxides, and protein carbonyls in primary passage 5 (P5) and senescent passage 25 (P25) and 30 (P30) fibroblasts. Cells were incubated in either standard Dulbecco growth medium (CM1) containing normal plasma selenium levels (0.8 μm… Show more
Selenium compounds exert their antioxidant activity mostly when the selenium atom is incorporated into selenoproteins. In our work, we tested the possibility that selenite itself interacts with thiols to form active species that have reducing properties. Therefore, we studied the reduction of 2-(4-carboxyphenyl)-4,5-dihydro-4,4,5,5-tetramethyl-1H-imidazol-1-yloxy-3-oxide radical (•cPTIO), damage of plasmid DNA (pDNA), modulation of rat hemodynamic parameters and tension of isolated arteries induced by products of interaction of selenite with thiols. We found that the products of selenite interaction with thiols had significant reducing properties that could be attributed mainly to the selenide and that selenite had catalytic properties in the access of thiols. The potency of thiols to reduce •cPTIO in the interaction with selenite was cysteine > homocysteine > glutathione reduced > N-acetylcysteine. Thiol/selenite products cleaved pDNA, with superoxide dismutase enhancing these effects suggesting a positive involvement of superoxide anion in the process. The observed •cPTIO reduction and pDNA cleavage were significantly lower when selenomethionine was used instead of selenite. The products of glutathione/selenite interaction affected several hemodynamic parameters including rat blood pressure decrease. Notably, the products relaxed isolated mesenteric artery, which may explain the observed decrease in rat blood pressure. In conclusion, we found that the thiol/selenite interaction products exhibited significant reducing properties which can be used in further studies of the treatment of pathological conditions caused by oxidative stress. The results of decreased rat blood pressure and the tension of mesenteric artery may be perspective in studies focused on cardiovascular disease and their prevention.
Selenium compounds exert their antioxidant activity mostly when the selenium atom is incorporated into selenoproteins. In our work, we tested the possibility that selenite itself interacts with thiols to form active species that have reducing properties. Therefore, we studied the reduction of 2-(4-carboxyphenyl)-4,5-dihydro-4,4,5,5-tetramethyl-1H-imidazol-1-yloxy-3-oxide radical (•cPTIO), damage of plasmid DNA (pDNA), modulation of rat hemodynamic parameters and tension of isolated arteries induced by products of interaction of selenite with thiols. We found that the products of selenite interaction with thiols had significant reducing properties that could be attributed mainly to the selenide and that selenite had catalytic properties in the access of thiols. The potency of thiols to reduce •cPTIO in the interaction with selenite was cysteine > homocysteine > glutathione reduced > N-acetylcysteine. Thiol/selenite products cleaved pDNA, with superoxide dismutase enhancing these effects suggesting a positive involvement of superoxide anion in the process. The observed •cPTIO reduction and pDNA cleavage were significantly lower when selenomethionine was used instead of selenite. The products of glutathione/selenite interaction affected several hemodynamic parameters including rat blood pressure decrease. Notably, the products relaxed isolated mesenteric artery, which may explain the observed decrease in rat blood pressure. In conclusion, we found that the thiol/selenite interaction products exhibited significant reducing properties which can be used in further studies of the treatment of pathological conditions caused by oxidative stress. The results of decreased rat blood pressure and the tension of mesenteric artery may be perspective in studies focused on cardiovascular disease and their prevention.
Humans exploit heavy metals for various industrial and economic reasons. Although some heavy metals are essential for normal physiology, others such as Tellurium (Te), Thallium (TI), antimony (Sb), and Osmium (Os) are highly toxic and can lead to Polycystic Ovarian Syndrome (PCOS), a common female factor of infertility. The current study was undertaken to determine levels of the heavy metals TI, Te, Sb and Os in serum of PCOS females (n = 50) compared to healthy non-PCOS controls (n = 56), and to relate such levels with Total Antioxidant Capacity (TAC), activity of key antioxidant enzymes, oxidative stress marker levels and redox status. PCOS serum samples demonstrated significantly higher levels of TI, Te, Sb and Os and diminished TAC compared to control (p < 0.001). Furthermore, there was significant inhibition of SOD, CAT and several glutathione-related enzyme activities in sera of PCOS patients with concurrent elevations in superoxide anions, hydrogen and lipid peroxides, and protein carbonyls, along with disrupted glutathione homeostasis compared to those of controls (p < 0.001 for all parameters). Additionally, a significant negative correlation was found between the elevated levels of heavy metals and TAC, indicative of the role of metal-induced oxidative stress as a prominent phenomenon associated with the pathophysiology of the underlying PCOS. Data obtained in the study suggest toxic metals as risk factors causing PCOS, and thus protective measures should be considered to minimize exposure to prevent such reproductive anomalies.
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