Plasma Glutathione and Glutathione Disulfide Levels in the Rat when Subjected to Combinations of Endotoxins, Hepatic lschemiaReperfusion, Cecal Ligation and Puncture, and Complement Activation
Michaels, Anothony J. (Tony)
The main purpose of this study was to set up different models that would produce various levels of oxidative stress. The oxidative stress was measured in male Fischer and Sprague-Dawley rats subjected to a variety of insults through glutathione disulfide (GSSG) levels that were monitored intracellularly (tissue samples) and extracellularly (plasma samples). Glutathione levels were measured after injections of paraquat and endotoxin (Salmonella entertidis, Salmonella abortus equi and E. coli), and after 45 min hepatic ischemia followed by 2 h reperfusion combined with cecal ligation and puncture (CLP) , endotoxin, or saline. Complement activation was also observed with cobra venom factor (CVF), and with CVF + CLP. The greatest stress was seen in the animals that were subjected to insults of 45 min ischemia + 2 h reperfusion + 1 µg/kg S. entertidis. The percentage of GSSG observed in the plasma was as high as 66%. The animals that were subjected only to insults of endotoxin did not show a higher stress than the ischemia animals, but oxidative stress was definitely occurring. The highest percentage of oxidized glutathione in the plasma was seen when the animals were given injections of 60 mg/kg of the redox-cycling agent paraquat. The GSSG percentage in the plasma was as high as 55% with animals subjected to paraquat. The results did not show much evidence for intracellular oxidative stress occurring. The livers and lungs isolated from the animals after the endotoxemia experiments showed a less than 1% oxidative glutathione in the tissue. Therefore, the majority of the results demonstrate a priming of Kupffer cells and neutrophils for reactive oxygen production occurring mainlyextracellularly. A greater stress causes a greater build up of oxygen radicals, causing an increase in GSSG as it becomes oxidized from GSH. These results may further help the scientific community to fight the excessive inflammatory response often seen after major traumas.
vi, 36 p.
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