Effects of the Free Radical Scavenger Dimethyl Sulphoxide on Experimental Normothermic Ischaemia of the Liver

Abstract

Background/Aims: This study assessed the effects of intermittent or continuous hepatic ischaemia and reperfusion with or without dimethyl sulphoxide (DMSO) pre-treatment in a rat ischaemic model. Methods: One hundred and eighty rats were divided into three groups undergoing hepatic ischaemia of a total duration of 60, 90 and 120 min. Each group of rats was subdivided to receive either a continuous Pringle manoeuvre or intermittent liver pedicle clamping of 30 or 15 min. Ten minutes before ischaemia induction, 10 rats from each group were pre-treated with DMSO (500 mg/kg, b.w.) intravenously. Results: With continuous hepatic pedicle clamping, survival rates inversely correlated with the duration of ischaemia, with greater survival in the intermittently clamped groups (p < 0.05). DMSO pre-treatment did not affect survival but resulted in a significant reduction in liver enzyme (aspartate aminotransferase, alanine aminotransferase) release on the first postoperative day following total ischaemic times of 90 min or greater (p < 0.05). After 120 min of total ischaemia, DMSO pre-treatment resulted in higher preservation of adenosine 5′-triphosphate liver content (p < 0.05). Conclusion: DMSO may be used to prolong tolerance to inflow occlusion and to limit the adverse effects of ischaemia and reperfusion cycles in an experimental hepatic ischaemia model.

Bovine rod rhodopsin. 1. Bleaching by luminescence in vitro by recombination of radicals from polyunsaturated fatty acids

“…In particular, as reported under Materials and methods, addition of 4% DMSO (w/v) quenches the radicals generated by the xanthine/ xanthine oxidase enzymatic system, interrupting propagation reactions [24][25][26][27][28][29]: rhodopsin in RdOS was in this case unaffected by radical generation. The integrity of the samples was checked in by subsequent bleaching by light and successful regeneration by the addition of 11-cis-retinal.…”

“…Here we show that RdOS rhodopsin is experimentally bleached by this mechanism and, then, able to detect the luminescent photons that are generated by lipids located nearby owing to the nature of membrane proteins [22][23][24][25][26][27][28][29].…”

Hypothermia and Amiloride Preserve Energetics in a Neonatal Brain Slice Model

“…Secondly, KHB and HEPES buffers were gassed with 95% O 2 /5% CO 2 and 100% O 2 , respectively, which may have generated suboptimal conditions due to the associated increased production of oxygen free radicals (34). Thirdly, amiloride was dissolved in DMSO and brain slices were exposed to a concentration of 0.01% DMSO over 8 h. Such a small concentration is unlikely to affect brain slice energetics, however, as DMSO is a free radical scavenger that in higher concentrations appears to preserve ATP after ischemia-induced damage in the liver (35), further studies should include controls exposed to DMSO alone to differentiate mechanisms of amiloride/DMSO treatment. Finally, the interrelationship of PCr, creatine kinase equilibrium, and pH is complex (36), so a comparison of PCr/Pi at different pH values needs caution.…”