Polyethylene glycol-conjugated superoxide dismutase fails to augment brain superoxide dismutase activity in piglets.
We studied the effect of intravenously administered polyethylene glycol-conjugated superoxide dismutase (8,000 units/kg) on brain superoxide dismutase activity in 44 1-2-week-old piglets in the absence and presence of global cerebral ischemia and reperfusion. Four groups (n = 6 each) of piglets not exposed to ischemia were studied. Enzyme administration increased plasma superoxide dismutase activity from less than 5 to 142 +/- 8 units/ml (mean +/- SEM) without increasing brain activity (e.g., activities in the caudate were 7.9 +/- 0.5 and 8.1 +/- 0.4 units/mg protein) for up to 2 hours following administration. Four additional groups (n = 5 each) of piglets were given either enzyme or polyethylene glycol 5 minutes prior to 10 minutes of global cerebral ischemia induced by aortic cross-clamping followed by either 5 or 45 minutes of reperfusion. Enzyme administration increased plasma superoxide dismutase activity from less than 5 to 144 +/- 5 units/ml but failed to increase brain activity even after 45 minutes of reperfusion (e.g., activities in the caudate were 8.5 +/- 0.3 and 8.6 +/- 0.6 units/mg protein). We conclude that intravenous polyethylene glycol-conjugated superoxide dismutase does not increase superoxide dismutase activity in the brain despite global ischemia and reperfusion.
Haun
S E
SE
Department of Anesthesiology/Critical Care Medicine, Johns Hopkins Medical Institutions, Baltimore, Md.
Kirsch
J R
JR
Helfaer
M A
MA
Kubos
K L
KL
Traystman
R J
RJ
D000818:Animals; D000831:Animals, Newborn; D001921:Brain / Q000201:enzymology*; D011092:Polyethylene Glycols / Q000008:administration & dosage / Q000494:pharmacology*; D013482:Superoxide Dismutase / Q000008:administration & dosage / Q000378:metabolism* / Q000494:pharmacology; D013552:Swine
D011092:Polyethylene Glycols; D013482:Superoxide Dismutase