Abstract P36: Active Hyperthermia Does Not Have Anti-inflammatory Effects to Endotoxin-induced Shock in Rats
Endotoxin shock, a common problem in patients with endotoxemia that often resists even intensive medical treatment, is characterized by profound hypotension, progressive metabolic acidosis, and dysfunction of multiple organs. Several investigators have documented that hyperthermia has an organ-protective effect in controlled hemorrhagic shock and provides myocardial protection. However, there are few reports whether active hyperthermia has the beneficial effects on endotoxemia or sepsis. Therefore we investigated effects of active hyperthermia on endotoxemic rats We hypothesize that active hyperthermia has beneficial effects on endotoxemia in vivo.
<Material and Methods> Male Sprague Dawley rats (n=40) were used and anesthetized with pentobarbital ip. Animals were randomly assigned to one of four groups: Group NE, Escherichia coli endotoxin (15 mg/kg, i.v.) in normothermia (36 to 38°C), Group HE, endotoxin in hyperthermia (39 to 40°C), Group NS, 0.9% saline in normothermia, and Group HS, 0.9% saline in hyperthermia. Rats then were warmed or cooled to maintain rectal temperatures as above for 8 hr. Mortality rate was assessed up to 8hr after endotoxin or saline. In addition, we assessed hemodynamics, acid-base status, and plasma cytokine concentrations. Endotoxemic rats developed hypotension and metabolic acidosis as well as increased plasma cytokine concentrations. Mortality rates 8 hrs after endotoxin or saline injection were 90%, 100%, 0% and 10% for the group NE, HE, NS, HS, respectively. Hypotension, acidosis, and increases in plasma cytokine (TNF-alpha and IL-6) concentrations were not different compared group NE with group HE. The present study showed that active hyperthermia did not attenuate the mortality rate and inflammatory responses to endotoxin-induced shock in rats. These findings suggest that active hyperthermia may not have anti-inflammatory effects in septic patients.