HMOX1 and infectious otitis media: Protein expression of Nrf2 and Nrf2 downstream targets TR, γ-GCSc and γ-GCSm and mRNA expression of GR, TR, HO-1, γ-GCSc, γ-GCSm, NQO-1, UGT1A1 and UGT1A10 were slightly changed in AOM group, indicating induction of the Nrf2 pathway by colon oxidative stress.