A number of scavengers of reactive
oxygen metabolites reduce myocardial injury when given before
ischemia and reperfusion, but few, if any, have proven to be effective when given near the onset of reperfusion. This is particularly true when
infarct size is measured after at least 48 hours of reperfusion, when the full extent of myocardial damage has become apparent.
Dimethylthiourea (
DMTU) is an extremely diffusible, potent scavenger of
hydroxyl radical,
hydrogen peroxide, and
hypochlorous acid, with a long half-life of 43 hours. Sixteen
chloralose-anesthetized dogs underwent 90 minutes of left anterior descending coronary artery (LAD) occlusion followed by 48 hours of reperfusion. Collateral flow was measured by radioactive
microspheres.
Infarct size and risk area were measured by a postmortem dual-perfusion technique using triphenyl tetrazolium
chloride and
Evan's blue dye. In eight dogs, therapy with
DMTU (500 mg/kg i.v.) was given during the last 15 minutes of
ischemia and the first 15 minutes of reperfusion. In eight control dogs, the same volume of
0.9% saline was given during the last 15 minutes of
ischemia through the first 15 minutes of reperfusion.
Infarct size as a percent of risk area was reduced in the
DMTU-treated group compared with the saline-treated controls (
DMTU = 42 +/- 4% versus saline = 59 +/- 4%, p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)