Identification of free radicals in myocardial ischemia/reperfusion by spin trapping with nitrone DMPO

Arroyo, Carmen M.; Kramer, Jay H.; Dickens, Benjamin F.; Weglicki, William B.

doi:10.1016/0014-5793(87)80360-5

Cited by 344 publications

(64 citation statements)

References 20 publications

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“…Moreover, ODFR have recently been detected with e.p.r. spectroscopy in perfusates of reperfused rat hearts as adducts of the spin-traps DMPO (5,5'-dimethyl-l-pyrroline-N-oxide [16,47]) or PBN (N-tertbutyl-a-phenylnitrone [48]). Recently we have confirmed these observations using DMPO (A. M. M. van der Kraaij, J. F. Koster & W. R. Hagen, unpublished work).…”

Section: Discussionmentioning

confidence: 99%

Reappraisal of the e.p.r. signals in (post)-ischaemic cardiac tissue

Kraaij

Koster

Hagen

1989

Biochemical Journal

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The present study was designed to measure directly, using e.p.r. spectroscopy, oxygen-derived free radicals in (post)-ischaemic or (post)-anoxic rat hearts. Rat hearts were rapidly freeze-clamped at 77 K under normoxic, anoxic, ischaemic or reperfusion conditions. The samples were measured at three different temperatures (13, 77 and 115 K) and at several microwave power levels, and were compared with isolated rat heart mitochondria. Samples were prepared both by grinding and as tissue cuts. The two preparation techniques gave identical e.p.r. results, which excludes the occurrence of grinding artifacts. No free radical signals linked to reperfusion injury were detected. Several electron transfer centres known in the mitochondrial respiratory chain were measured. The signals previously assigned to post-ischaemic reperfusion injury were found to originate from electron transfer centres of the respiratory chain, predominantly the iron-sulphur cluster S-1 in succinate dehydrogenase. The differences in signal intensity between normoxic, ischaemic and reperfused hearts were found to result from the different redox stages of these centres under the various conditions tested. These findings do not necessarily imply that oxygenderived free radicals are not formed in cardiac tissue during (post)-ischaemic reperfusion. The constitutive background of paramagnetism from the respiratory chain, however, seriously hampers the direct detection of comparatively low concentrations of free radicals in cardiac tissue. It is therefore expedient to focus future experiments in this field on the use of spin-trapping agents.

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Section: Discussionmentioning

confidence: 99%

Reappraisal of the e.p.r. signals in (post)-ischaemic cardiac tissue

Kraaij

Koster

Hagen

1989

Biochemical Journal

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“…Thus, ferric iron (Fe"') in an aqueous chloride solution can catalyse the oxidation of 5,5-dimethyl-1-pyrroline N-oxide (DMPO) into hydroxamic acid and then into the corresponding nitroxide. Similarly it has been suggested [13] that the iron present in trace amounts in buffers can produce the dimerization of DMPO, generating an artefactual ESR signal of 6 bands with splitting constants of aN = 15.3 I G, and aH = 22.0 G. Several spin-trapping studies using DMPO in isolated rat [8,9] or rabbit [ 121 hearts have described the occurrence of a sextet signal in coronary effluents collected during post-ischaemic reperfusion. This signal was attributed to the trapping of alkyl or alkoxyl radicals formed during reperfusion.…”

Section: Introductionmentioning

confidence: 95%

Evidence of cytosolic iron release during post‐ischaemic reperfusion of isolated rat hearts Influence on spin‐trapping experiments with DMPO

et al. 1992

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“…0~ lo9 M-' s-' for the dismutation reaction 2'0; + 2 H + +02 + H 2 0 2 [7]), high dosages of superoxide dismutase could indirectly stabilize the ascorbyl radical, possibly allowing its ESR detection. Although we have checked that superoxide disinutase alone seems unable to enhance ascorbyl radical formation in vitro from sodium ascorbate under our experimental conditions, the observation in coronary effluents (pointed out by Arroyo et al [16] but not explicitly mentioned by Zweier [l 11) of very weak ascorbylradical ESR signals only in experiments using superoxide dis-mutase, possibly reflects such a stabilizing effect, particularly when maximal release of ascorbate ion is reached (i.e. after 30min of low-flow ischemia [16] and 5min of post-global ischemia reperfusion [ll]).…”

Section: Implication Of Superoxidtr-mediated Free-radical-generation mentioning

confidence: 84%

Ascorbyl free radical as a reliable indicator of free‐radical‐mediated myocardial ischemic and post‐ischemic injury

Pietri

Culcasi

Stella

et al. 1990

European Journal of Biochemistry

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The real-time kinetics of the release of ascorbyl free radicals in the coronary perfusate from isolated rat hearts submitted to an ischemia/reperfusion sequence has been achieved by continuous-flow ESR using high-speed acquisition techniques. Enhanced ESR detection of ascorbyl free radicals was obtained by addition of dimethyl sulfoxide (Me,SO), a strong cation chelator and oxidizing agent. A continuous-flow device allowed a direct monitoring of the ascorbyl free radical and/or ascorbate leakage in coronary perfusate by observation of the ascorbyl radical doublet (aH = 0.188 mT and g = 2.0054).1. The results showed that ascorbyl free radical release occurred mainly during sequences of low-flow ischemia (90 min) coupled or not with 30 min of zero-flow ischemia followed by reperfusion (60 min). The kinetic profiles of ascorbyl-free-radical detection confirm in quantitative terms the expected correlation between the duration of the ischemic insult and the magnitude of ascorbate extracellular release upon reperfusion. There is indication that ascorbyl free radical depletion could be secondary to oxygen-derived-free-radical-induced cellular damage.2. The amount of residual ascorbic acid was quantitated on myocardial tissue at the end of reperfusion using Me2S0 as extracting solvent. Intense oxidation of ascorbate and chemical stabilization of the resulting free radical species provided by MezSO allowed ESR measurement of a marked tissue ascorbate depletion related to the duration of ischemia.3. Perfusion of superoxide dismutase during low-flow ischemia and the first 10 min of reperfusion greatly inhibited both extracellular release and endogenous ascorbate depletion. These results suggest that the ascorbate redox system constitutes a

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Identification of free radicals in myocardial ischemia/reperfusion by spin trapping with nitrone DMPO

Cited by 344 publications

References 20 publications

Reappraisal of the e.p.r. signals in (post)-ischaemic cardiac tissue

Reappraisal of the e.p.r. signals in (post)-ischaemic cardiac tissue

Evidence of cytosolic iron release during post‐ischaemic reperfusion of isolated rat hearts Influence on spin‐trapping experiments with DMPO

Ascorbyl free radical as a reliable indicator of free‐radical‐mediated myocardial ischemic and post‐ischemic injury

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