Introduction: We have previously described a robust thermoregulatory response to middle cerebral artery occlusion (MCAO) in rats which results in both brain and body hyperthermia. Interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) are pro-inflammatory cytokines and potent endogenous pyrogens which also play a role in the pathogenesis of cerebral ischemia-reperfusion injury. The present study was designed to determine the regional distribution of IL-1β and TNF-α in the brain during and after MCAO in rats. Methods: Fasted adult male rats underwent MCAO (intraluminal suture method) for up to 2h and up to 3h reperfusion. Rectal temperature was measured by thermocouple. Regional distribution of IL-1β and TNF-α was assessed by immunocytochemistry, and brain concentration was measured by ELISA in 3-4 rats at the following time points: 1h and 2h MCAO, and 1h and 3h reperfusion after 2h MCAO. Plasma concentration of IL-1β and TNF-α was measured by ELISA at baseline and at sacrifice. Data (mean ±SEM) were analyzed by ANOVA and Kruskal-Wallis (*p<0.05). Results: Rectal temperature increased from 37.2±0.1°C at baseline to 38.6±0.1* and 39.1±0.2°C* at 1h and 2h MCAO, then decreased to 38.5±0.3°C* at 3h reperfusion. IL-1β and TNF-α were not detected in plasma at any time point Expression of TNF-α was greater than that of IL-1β in the cortex and striatum during MCAO and early reperfusion. * However, in the preoptic area of the hypothalamus immunostaining for IL-1β appeared to be greater than that for TNF-α and was not limited to the ischemic hemisphere. Conclusions: These preliminary data suggest that TNF-α is more involved than IL-1β in early cerebral ischemia-reperfusion events, whereas IL-1β may play a greater role in the development of hyperthermia during MCAO in rats.
|Original language||English (US)|
|Journal||Critical care medicine|
|Issue number||1 SUPPL.|
|State||Published - Dec 1 1999|
ASJC Scopus subject areas
- Critical Care and Intensive Care Medicine