Figure 8. Stress preconditioning reduces cytokine-stimulated nitrite production by A549 or primary cultures of rat alveolar epithelial type II cell monolayers.

Control cells were maintained in basal growth media. Cytokine-treated cells were exposed to a mixture of pro-inflammatory cytokines (TNF-α, IL-1β, IFN-γ) for 24 h at a concentration of 10 ng ml⁻¹. A group of cells were stress preconditioned with heat (43 °C for 60 min for A549 cells and 30 min for ATII cells) 12 h before exposure to pro-inflammatory cytokines. Nitrite production in the cell culture medium 24 h after exposure to cytomix or its vehicle is shown for cell monolayers that were (n = 4) or were not stress preconditioned (n = 4) with heat. *P < 0.05 from controls; ** P < 0.05 from cell monolayers that were exposed to cytomix, but not stress preconditioned with heat.