Hyperoxia increases ventilator-induced lung injury via mitogen-activated protein kinases: a prospective, controlled animal experiment

Table 1 Experimental design and numbers of animals per group

	Control (WT, JNK KO)	Control + O2 (WT, JNK KO)	V_T of 30 ml/kg	V_T of 30 ml/kg + O2	V_T of 30 ml/kg + JNK1 KO	V_T of 30 ml/kg + JNK1 KO + O2	V_T of 30 ml/kg + ERK inhibitor	V_T of 30 ml/kg + ERK inhibitor + O2
MPO, MIP-2 (5 hours of ventilation)	5	5	5	5	5	5	5	5
JNK, p38, ERK (1 hour of ventilation)	5	5	5	5	5	5	5	5
PARP (1, 2, and 5 hours of ventilation)	5	5	5	5	5	5	5	5
MIP-2 mRNA (1 hour of ventilation)	5	5	5	5	5	5	5	5
EBD assay (5 hours of ventilation)	5	5	5	5	5	5	5	5
AP-1, NF-κB (1 hour of ventilation)	5	5	5	5	5	5	5	5
IHC assay (5 hours of ventilation)	5	5	5	5	5	5	5	5
TUNEL assay (5 hours of ventilation)	5	5	5	5
Electron microscopy	2	2	2	2

AP-1 and NF-κB binding; total expression and phosphorylated forms of JNK, p38, and ERK1/2; PARP; IHC; and MIP-2 mRNA expression were measured in lung tissue. Time points for measurements were determined according to our previous findings that mediator activation occurs early in ventilator-induced lung injury and neutrophil infiltration occurs later [20]. AP-1, activator protein-1; Control, spontaneously breathing, non-ventilated mice; EBD, Evans blue dye (a measurement of microvascular leak in the lung); ERK, extracellular signal-regulated kinase; IHC, immunohistochemical stain; JNK, c-Jun NH₂-terminal kinase; KO, knockout; MIP-2, macrophage inflammatory protein-2 (a functional homolog of IL-8); MPO, myeloperoxidase (a measurement of total neutrophil infiltration in the lung); NF-κB, nuclear factor-kappa-B; O2, hyperoxia; PARP, poly (ADP-ribose) polymerase; TUNEL, terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end-labeling, a measurement of apoptotic cells in the lung; V_T, tidal volume; WT, wild-type.

ISSN: 1364-8535