title: Differential protection against oxidative stress and nitric oxide overproduction in cardiovascular and pulmonary systems by propofol during endotoxemia.
abstract: BACKGROUND
  Both overproduction of nitric oxide (NO) and oxidative injury of cardiovascular and pulmonary systems contribute to fatal cardiovascular depression during endotoxemia. We investigated in the present study the relative contribution of oxidative stress and NO to cardiovascular depression during different stages of endotoxemia, and delineated their roles in cardiovascular protective effects of a commonly used anesthetic propofol during endotoxemia.
  
  
  METHODS
  Experimental endotoxemia was induced by systemic injection of E. coli lipopolysaccharide (LPS, 15 mg/kg) to Sprague-Dawley rats that were maintained under propofol (15 or 30 mg/kg/h, i.v.) anesthesia. Mean systemic arterial pressure (MSAP) and heart rate (HR) were monitored for 6 h after the endotoxin. Tissue level of NO was measured by chemical reduction-linked chemiluminescence and oxidative burst activity was determined using dihydroethidium method. Expression of NO synthase (NOS) was determined by immunoblotting. The Scheffé multiple range test was used for post hoc statistical analysis.
  
  
  RESULTS
  Systemic injection of LPS (15 mg/kg) induced biphasic decreases in MSAP and HR. In the heart, lung and aorta, an abrupt increase in lipid peroxidation, our experimental index of oxidative tissue injury, was detected in early stage and sustained during late stage cardiovascular depression. LPS injection, on the other hand, induced a gradual increase in tissue nitrite and nitrate levels in the same organs that peaked during late stage endotoxemia. Propofol infusion (15 or 30 mg/kg/h, i.v.) significantly attenuated lipid peroxidation in the heart, lung and aorta during early and late stage endotoxemia. High dose (30 mg/kg/h, i.v.) propofol also reversed the LPS-induced inducible NO synthase (iNOS) upregulation and NO production in the aorta, alongside a significant amelioration of late stage cardiovascular depression and increase in survival time during endotoxemia.
  
  
  CONCLUSIONS
  Together these results suggest that oxidative injury and NO may play a differential role in LPS-induced cardiovascular depression. Oxidative tissue injury is associated with both early and late stage; whereas NO is engaged primarily in late stage cardiovascular depression. Moreover, propofol anesthesia may protect against fatal cardiovascular depression during endotoxemia by attenuating the late stage NO surge in the aorta, possibly via inhibition of iNOS upregulation by the endotoxin.
authors.affiliation: Department of Biological Science and Center for Neuroscience, National Sun Yat-sen University, Kaohsiung, Taiwan. inp1965@mail.ncku.edu.tw
authors.forename: Yen-Chin
authors.initials: YC
authors.lastname: Liu
authors.forename: Alice Y W
authors.initials: AY
authors.lastname: Chang
authors.forename: Yu-Chuan
authors.initials: YC
authors.lastname: Tsai
authors.forename: Julie Y H
authors.initials: JY
authors.lastname: Chan
mesh_terms: D018686:Anesthetics, Intravenous / Q000494:pharmacology; D000818:Animals; D002319:Cardiovascular System / Q000187:drug effects*; D019446:Endotoxemia / Q000139:chemically induced / Q000503:physiopathology*; D006801:Humans; D007527:Isoenzymes / Q000378:metabolism; D015227:Lipid Peroxidation; D008070:Lipopolysaccharides / Q000276:immunology / Q000494:pharmacology; D008168:Lung / Q000187:drug effects*; D008297:Male; D008315:Malondialdehyde / Q000378:metabolism; D009569:Nitric Oxide / Q000009:adverse effects / Q000378:metabolism*; D019001:Nitric Oxide Synthase / Q000378:metabolism; D018384:Oxidative Stress / Q000187:drug effects*; D015742:Propofol / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D016897:Respiratory Burst
chemical_list: D018686:Anesthetics, Intravenous; D007527:Isoenzymes; D008070:Lipopolysaccharides; D009569:Nitric Oxide; D008315:Malondialdehyde; D019001:Nitric Oxide Synthase; D015742:Propofol