PepT1 mediated MDP transport induces small intestinal pathological injury. (A) The survival in each group was assessed in MDP and MDP + Gly-Gly groups. (B) The intestinal weight was measured at the 1st, 2nd, 3rd, 4th, 5th, 6th, and 7th day in MDP and MDP + Gly-Gly groups. (C) HE staining of small intestine in each group. 100× magnification. PepT1, peptide transporter; MDP, muramyl dipeptide; HE, hematoxylin and eosin.