Sc. Widman et al., CONTRACTION BAND NECROSIS - ITS MODIFICATION BY THE FREE-RADICAL SCAVENGER N-2-MERCAPTOPROPIONYL GLYCINE, Journal of cardiovascular pharmacology, 24(5), 1994, pp. 694-701
Contraction band necrosis (CBN) may represent infarct extension from f
ree radical generation during reperfusion. We sought to limit CBN with
the free radical scavenger N-2-mercaptopropionyl glycine (MPG, 20 mg/
kg). Sixteen chronically instrumented Beagles (8 control, and 8 MPG tr
eated) underwent 90-min left anterior descending coronary artery (LAD)
occlusion followed by 6-h reperfusion. Coronary blood flow (CBF) was
measured by the radioactive microsphere technique. The dogs were kille
d, and the hearts were perfused with red and blue dyes to determine ar
ea at risk (AAR), stained with nitroblue tetrazolium for infarct local
ization, and sectioned for histologic analysis and BF measurements. In
controls and MPG-treated animals, infarct/risk ratios were 40 +/- 5 a
nd 38 +/- 6%, and epicardial collateral BFs were 0.21 +/- 0.037 and 0.
15 +/- 0.034 ml/g/min, respectively (p = NS). Hemodynamic measurements
did not differ between the two groups. However, CBN as a percentage o
f total infarct was reduced in controls (22 +/- 3%) as compared with M
PG-treated animals (35 +/- 2%, p = 0.002). Thus, MPG altered the histo
logic composition of infarcts in this model, surprisingly increasing t
he amount of CBN without altering overall infarct size (IS). These res
ults raise questions about the role of free radical scavengers in gene
ration of CBN and suggest that a population of cells exists in which t
reatment with MPG may alter the mechanism of cell death.