mPGES-1 genetic deletion results in reduced collagen content and myofibroblast formation in vivo. (a) Hydroxyproline analysis showed reduced collagen content in mPGES-1 null mice compared with wild-type (WT) mice in response to bleomycin treatment. Data from four separate mice per group are shown. (b, c) Immunohistochemistry using anti-α-SMA antibody was performed. mPGES-1 null mice showed a reduced number of α-SMA-expressing myofibroblasts compared with WT mice in response to bleomycin treatment (4-week treatment). Representative data from four separate animals per group are shown. *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. (d) Protein extracts from skin tissue after 4 weeks of bleomycin or PBS treatment were subjected to Western blot analysis with an anti-α-SMA antibody. mPGES-1 null mice treated with bleomycin showed reduced α-SMA expression compared with bleomycin-treated WT mice. Representative blot from four separate animals per group is shown. α-SMA, alpha-smooth muscle actin; mPGES-1, microsomal prostaglandin E2 synthase-1.