Cyclooxygenase expression and NF-κB activation in thoracic exudates differ between male and female cells. Rats were treated with carrageenan (intra thoracic injection) and sacrificed after 4 hrs. (A) Numbers of infiltrated cells (106/rat) were measured in a Burker chamber using light microscopy. (B) Analysis of COX-1/2, (E) phospho-NF-κB p65 and (G) phospho-p38 MAPK by Western blot in total cell lysates of thoracic exudates from male and female carrageenan-treated rats. Densitometric analysis of (C) COX-1, (D) COX-2, (F) phospho-NF-κB p65 and (H) phospho-p38 MAPK protein normalized to β-actin expression. Values represents means ± S.E.M., n = 4 rats. #p < 0.05; ##p < 0.01, male vs female; two-tailed Student’s t test.