mPGES-1 null mice show resistance to bleomycin-induced fibrosis in vivo. (a) Trichrome staining was performed to account for collagen content (degree of fibrosis) and dermal thickness in response to bleomycin treatment (4-week bleomycin treatment). (b) mPGES-1 null mice exhibited reduced dermal thickness compared with wild-type (WT) mice in response to bleomycin treatment. (c) Blind histological analysis in trichrome-stained sections showed that bleomycin-treated mPGES-1 null mice exhibited reduced collagen score compared with bleomycin-treated WT mice. *P < 0.05; bleomycin-treated WT and mPGES-1 null mice compared with phosphate-buffered saline (PBS)-treated mice. +P < 0.05; bleomycin-treated mPGES-1 null mice compared with bleomycin-treated WT mice. Representative data from four separate animals per group are shown. mPGES-1, microsomal prostaglandin E2 sythnase-1.