As PDIA2 is one of the ER chaperone protein family members that are usually upregulated in response to ER stress, we further confirmed if AOM/DSS treatment induces ER stress by analyzing the phosphorylation status of inositol-requiring transmembrane kinase/endoribonuclease 1α (IRE1α) (another biomarker of ER stress) in colon mucosa. This evidence concerns the gene ERN1 and infectious otitis media.