Deficiency of TLR4 attenuates HS/R-induced acute lung inflammation. Wild type (WT) and TLR4-/- mice were subjected to either sham or HS/R and mouse circulating HMGB1 (A), lung MPO activity (B) and pulmonary protein leakage (C) were determined 24 hrs after resuscitation. A. Five mice in each group, *p < 0.05 vs. WT sham; +p < 0.05 vs. TLR4-/- sham; no difference between WT HS/R and TLR4-/- HS/R; B and C. Five mice in each group. *p < 0.05 vs WT sham, #p < 0.05 vs WT HS/R.