Fig. 9.

Heat-shock-induced interleukin (IL)-8 secretion in crypt-like (a) and villus-like (b) Caco-2 cells after preincubation with butyrate. After exposure to physiological butyrate concentrations (0–20 m M) for 24 h, the control (1 h 37°C) and heat-shocked (1 h 42°C) cells were allowed to recover for 6 h. During the subsequent heat shock and recovery period, butyrate exposure was continued. IL-8 secretion is expressed as pg IL-8/10⁶ cells. Heat-shock-induced IL-8 secretion was determined using two cell passages and triplicate cultures per passage. Significant differences (*P < 0·05) between the levels of IL-8 of heat-shocked cells and control Caco-2 cells are indicated.