Fig. 2. Functional toll-like receptor (TLR) 4 is required for full pathologic response to ventilated lung ischemia-reperfusion (I-R) injury. Inflammatory cytokines and chemokine induction (mRNA) at 1 h after reperfusion measured in lung samples from C3H TLR4mut versus  wild-type mice using Q-PCR. All measurements were normalized to glyceraldehyde 3-phosphate dehydrogenase (GAPDH) message levels. Each point represents RNA from left lung lower segments of individual C3H wild-type or C3H TLR4mut mice that underwent I-R surgery. Mice that died before completion of surgery or collection of lungs or had inadvertent esophageal intubation and required multiple reintubation attempts were excluded from analysis (2 C3H wild-type and 1 C3H TLR4mut mouse) (A) . Hematoxylin and eosin histopathology of C3H wild-type and C3H TLR4 mut mice left lungs at 3 h after reperfusion after I-R surgery. Each image is representative of histologic images from three independent surgeries (B) . Analysis of relative mRNA levels of inflammatory markers (as noted) for left lower lung segments from C57BL/6 wild-type mice versus  C57BL/6 TLR2−/− mice at 1 h after reperfusion after I-R surgery. Each point represents RNA from left lung lower segments of individual wild-type or TLR2ko mice that underwent I-R surgery. One wild-type mouse died before completion of surgery and was excluded from analysis (C) . Histologic analysis of C57/BL6 wild-type versus  TLR2−/− left lungs after 30 min ischemia and 3 h reperfusion. Each image is representative of histologic images from two independent surgeries (D) . CXCL = chemokine (C-X-C motif) ligand; ICAM = intercellular adhesion molecule; IL = interleukin; mRNA = messenger RNA; WT = wild-type.