Immunohistochemical localization of Bax in the lung. Lung biopsies were taken 24 h after injection of carrageenan. No positive staining for Bax was observed in the lung tissues collected at 24 hours from sham WT mice (a) and from sham TNF-αR1KO mice (b). On the contrary, tissue sections obtained from WT animals at 24 hours (c) after carrageenan injection demonstrate positive staining for TNF-α mainly localized in the infiltrated inflammatory cells, pneumocytes as well as in vascular wall. In carrageenan-injected TNF-αR1KO mice, no positive staining for Bax were observed in the lung tissues collected at 24 hours (d). Similarly, the treatment of WT mice with Etanercept (5 mg/kg administered s.c. 2 h prior carrageenan) visibly and significantly reduced the positive staining for Bax in the infiltrated inflammatory cells, pneumocytes as well as in vascular wall in the lung tissues collected at 24 hours (e). Figure is representative of at least 3 experiments performed on different experimental days.