Changes in cell culture temperature alter release of inflammatory mediators in murine macrophagic RAW264.7 cells

Abstract

To examine whether moderate changes in cell culture temperature influence the production of various cytokines and associated mediators of inflammation. We performed lipopolysaccharide (LPS) stimulation of the murine macrophagic RAW264.7 cell line under hyperthermic (40 degrees C), normothermic (37 degrees C) and hypothermic (34 degrees C) conditions. We then measured the levels of heat shock protein 70 (HSP70), heat shock factor protein (HSF) and nuclear factor-kB (NF-kB) dimers (p50 and p65) in the cells, and the levels of high mobility group box 1 (HMGB1) and the cytokines tumor necrosis factor-alpha (TNF-alpha), interleukin 1beta (IL-1beta) and interleukin 6 (IL-6) in the culture supernatants. Levels of HMGB1, IL-1beta, IL-6, and TNF-alpha, as well as NF-kB dimers (p50 and p65), were all reduced following LPS stimulation at 40 degrees C and 34 degrees C compared with those at 37 degrees C. Levels of HSP70 and HSF increased at 40 degrees C and 34 degrees C. The application of moderate hyperthermia and hypothermia after LPS-induced cell activation attenuated the inflammatory response and reduced the likelihood of cell damage. These findings suggest that moderate temperature changes modulate the inflammatory response and could be a useful therapy against sepsis.