Potent inhibition of peroxynitrite-induced DNA strand breakage and hydroxyl radical formation by dimethyl sulfoxide at very low concentrations

Abstract

Dimethyl sulfoxide (DMSO) is frequently used as a solvent for many water-insoluble drugs in biological studies at concentrations often up to 1%. However, little is known about its effects on oxidatively generated DNA damage at very low concentrations (0.005-0.5%). This study was undertaken to investigate the effects of DMSO on peroxynitrite-induced DNA strand breaks, a critical event leading to peroxynitrite-elicited cytotoxicity. Incubation of varphiX-174 plasmid DNA, with 3-morpholinosydnonimine (SIN-1), a peroxynitrite generator, led to the formation of DNA strand breaks in a concentration- and time-dependent manner. The presence of DMSO at concentrations of 0.005-0.5% was found to significantly inhibit SIN-1-induced DNA strand breaks in a concentration-dependent manner. However, DMSO at the above concentrations showed no affect on SIN-1-mediated oxygen consumption, indicating that DMSO did not affect the auto-oxidation of SIN-1 to form peroxynitrite. It is observed that incubation of the plasmid DNA with authentic peroxynitrite resulted in significant formation of DNA strand breaks, which could also be dramatically inhibited by the presence of DMSO at 0.005-0.5%. Electron paramagnetic resonance spectroscopy, using 5,5-dimethylpyrroline-N-oxide (DMPO) as a spin trap demonstrated the formation of DMPO-hydroxyl radical adduct from the SIN-1 and authentic peroxynitrite. DMSO at the concentrations ranging from 0.01% to 0.5% significantly inhibited the adduct signal. Taken together, these studies demonstrate, for the first time, that DMSO at extremely low concentrations (0.005-0.5%) can potently inhibit peroxynitrite-mediated DNA strand breakage and hydroxyl radical formation. The results of this study suggest that, where DMSO is applied as a solvent, caution should be observed when evaluating the actions of drugs in experiments involving DNA damage.

Spironolactone and Dimethylsulfoxide Effect on Glucose Metabolism and Oxidative Stress Markers in Polycystic Ovarian Syndrome Rat Model

“…The literature data indicates that this controversial molecule has antioxidant, anti-infl ammatory and analgesic properties that make it suitable for the treatment of interstitial cystitis [ 34 ] , various complications of amiloidosis [ 35 ] , or various gastrointestinal diseases [ 36 ] . Because of its powerful antioxidative properties as a hydroxyl radical scavenger [ 37 ] , administration of DMSO completely prevented diabetes induction by alloxane in rats [ 38 ] . However, in frank diabetes induced by streptozotocin or alloxane, DMSO alone proves no hypoglycaemiant eff ect [ 39 , 40 ] .…”

EPR studies on hydroxyl radical-scavenging activities of pravastatin and fluvastatin

“…At a physiological pH, SIN-1 is known to undergo auto-oxidation to produce equal molar nitric oxide and superoxide, leading to the formation of peroxynitrite [37,38]. This system is often used in the examination of peroxynitrite on biological systems [20,37]. Thus, SIN-1 was used to further investigate whether pravastatin and fluvastatin can protect DNA damage caused by peroxynitrite.…”

“…Assay for oxidative DNA breaks DNA damage was measured by the conversion of supercoiled φX-174 RF I double-stranded DNA to open circle and linear forms [19,20]. In summary, 0.2 μg DNA was incubated with H 2 O 2 + Fe(II), SIN-1, fluvastatin or pravastatin in PBS at 37°C at a final volume of 24 μl for 30 min.…”

Evaluation of in vitro anti-inflammatory effects of crude ginger and rosemary extracts obtained through supercritical CO2 extraction on macrophage and tumor cell line: the influence of vehicle type

“…Moreover, when used as a delivery system, DMSO may alter in vitro ginger and rosemary extracts bioavailability and cytotoxicity. At very small and non-lethal concentrations, DMSO can be an exogenous antioxidant due to its ability to react with free radicals [ 30 ], acting as a radical scavenger that protects cells against compounds that increase intracellular levels of radical oxygen species [ 31 ]. This behavior, despite being desirable, may affect the analysis of potential pharmacological effectiveness of hydrophobic compounds in vitro.…”