title: Acute hyperhomocysteinemia alters the coagulation system and oxidative status in the blood of rats.
abstract: In the present study, we investigated the effect of the acute administration of homocysteine (Hcy) on parameters of the coagulation system, as well as fibrinogen and nitrite levels in the blood of rats. In addition, we evaluated the effect of acute hyperhomocysteinemia on thiobarbituric acid-reactive substances in plasma and on antioxidant enzymes activities (superoxide dismutase, catalase, and gluthatione peroxidase) in the erythrocytes of rats. Wistar rats, aged 29 days, received a single subcutaneous dorsal injection of saline (control) or Hcy (0.6 μmol/g body weight). Fifteen minutes, 1 h, 6 h or 12 h after the injection, the rats were euthanized and the blood, plasma, and erythrocytes were collected. Results showed that Hcy significantly increased platelet count in the blood and plasma fibrinogen levels of rats at 15 min and 1 h, but not at 6 h and 12 h, when compared with the control group. Prothrombin time, activated partial thromboplastin time, and nitrite levels significantly decreased in plasma at 15 min and 1 h, but not at 6 h and 12 h after Hcy administration. In addition, hyperhomocysteinemia increased thiobarbituric acid-reactive, an index of lipid peroxidation, in plasma at 15 min and 1 h; decreased the superoxide dismutase and gluthatione peroxidase activity, and increased the catalase activity at 15 min in erythrocytes of rats, suggesting that acute Hcy administration may alter the oxidative status in the blood of rats. Our findings suggest that hypercoagulability and oxidative stress can occur after acute hyperhomocysteinemia, possibly in association, at least in part, with the vascular dysfunction and thromboembolic complications observed in homocystinuric patients.
authors.affiliation: Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, ICBS, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.
authors.forename: Aline A
authors.initials: AA
authors.lastname: da Cunha
authors.forename: Emilene
authors.initials: E
authors.lastname: Scherer
authors.forename: Maira J
authors.initials: MJ
authors.lastname: da Cunha
authors.forename: Felipe
authors.initials: F
authors.lastname: Schmitz
authors.forename: Fernanda R
authors.initials: FR
authors.lastname: Machado
authors.forename: Daniela D
authors.initials: DD
authors.lastname: Lima
authors.forename: Débora
authors.initials: D
authors.lastname: Delwing
authors.forename: Angela T S
authors.initials: AT
authors.lastname: Wyse
mesh_terms: D000818:Animals; D001777:Blood Coagulation; D002374:Catalase / Q000097:blood; D004912:Erythrocytes / Q000201:enzymology; D005340:Fibrinogen / Q000378:metabolism; D005979:Glutathione Peroxidase / Q000097:blood; D020138:Hyperhomocysteinemia / Q000097:blood*; D009573:Nitrites / Q000097:blood; D018384:Oxidative Stress; D010314:Partial Thromboplastin Time; D010976:Platelet Count; D011517:Prothrombin Time; D051381:Rats; D017208:Rats, Wistar; D013482:Superoxide Dismutase / Q000097:blood; D017392:Thiobarbituric Acid Reactive Substances / Q000378:metabolism
chemical_list: D009573:Nitrites; D017392:Thiobarbituric Acid Reactive Substances; D005340:Fibrinogen; D002374:Catalase; D005979:Glutathione Peroxidase; D013482:Superoxide Dismutase