Fig. 4. (A ) Concentration of tumor necrosis factor (TNF)-α. (B ) Concentration of interleukin-1β. (C ) Concentration of macrophage inflammatory protein-2. (D ) Total protein concentration in bronchoalveolar lavage fluid. Rats ventilated with either 6 ml/kg tidal volume or high tidal volume injurious ventilation for 2 h with and without administration of sodium nitrite and alterations of nitric oxide bioavailability. The table below the figures depicts the experimental groups, ventilatory regime, and treatment strategies. Values are means ± SD; P < 0.05 and *versus  low tidal volume ventilation, #versus  high-tidal volume ventilation. Numbers within error bars  depict sample size. Note that 10⁰signifies a value below the detection threshold. Allo = allopurinol; BAL = bronchoalveolar lavage; C-PTIO = 2-(4-carboxyphenyl)-4,5dihydro-4,4,5,5-tetramethyl-1H-imidazolyl-1-oxy-3oxide; IL = interleukin; L-NAME = N^ω-nitro-L-arginine methyl ester; MIP = macrophage inflammatory protein; NaNO²= sodium nitrite; NO = nitric oxide; TNF = tumor necrosis factor; V^T= tidal volume.