TGFB1 and infectious otitis media: Our findings are in-line with these observations; compared to AOM-treated WT mice, livers from AOM-treated M1R-deficient mice had reduced peroxynitrite adduct formation and up-regulated expression of Gclc and Nqo1. GCLC promotes glutathione generation which scavenges peroxynitrite and free radicals, whereas NQO1 inhibits TGF-β-mediated activation of the fibrogenic response52.