Liposome-mediated augmentation of brain SOD and catalase inhibits CNS O2 toxicity.
Enzymes specific for O-2 and H2O2 metabolism [superoxide dismutase (SOD) and catalase] can be delivered to the rat brain following entrapment in liposomes and intravenous injection and will protect against hyperbaric O2-induced convulsions in rats. Liposome-mediated superoxide dismutase and catalase augmentation of brain enzyme activity was 2.7-fold and 1.9-fold, respectively, 15 min after intravenous injection of superoxide dismutase plus catalase-entrapped liposomes. Rats treated with liposomes containing superoxide dismutase plus catalase 2 h before 6 ATA 100% O2 exposure had the time to convulsion extended three times that of controls. This protective effect was dose-dependent and was primarily due to augmentation of catalase activity. These findings show O-2 and H2O2 are important mediators of hyperbaric O2-induced central nervous system toxicity and that liposome-mediated augmentation of brain antioxidant enzymes has a biological effect.
D000818:Animals; D001921:Brain / Q000201:enzymology*; D002374:Catalase / Q000627:therapeutic use*; D002490:Central Nervous System / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D006931:Hyperbaric Oxygenation / Q000009:adverse effects; D007275:Injections, Intravenous; D008081:Liposomes / Q000008:administration & dosage* / Q000032:analysis; D008297:Male; D010100:Oxygen / Q000633:toxicity*; D051381:Rats; D011919:Rats, Inbred Strains; D012640:Seizures / Q000139:chemically induced / Q000517:prevention & control; D013482:Superoxide Dismutase / Q000627:therapeutic use*; D013997:Time Factors
D008081:Liposomes; D002374:Catalase; D013482:Superoxide Dismutase; D010100:Oxygen