Fig 2: Gut microbial tryptophan derivatives relieve MCT-induced liver oxidative injury via the AhR/Nrf2 signaling. A, B The mRNA and protein expression of nuclear AhR in live tissues. C-D The CYP1A1 mRNA and protein expression of. E–F The mRNA and protein expression of nuclear Nrf2 in live tissues. G The GCLC, GCLM and NQO1 mRNA expression. H–K The MDA amount, ROS level, GST activity and GSH/GSSG ratio in liver tissue. Data are expressed as mean ± SEM. N = 4. *P < 0.05, **P < 0.01, vs. Control group; #P < 0.05, ##P < 0.01, vs. MCT group. MCT, monocrotaline; HSOS, hepatic sinus obstruction syndrome; IAAld, Indole-3-Acetaldehyde; IAA, Indole Acetic Acid; Ficz, 6-Formylindolo[3,2-b]carbazole; AhR, aromatic hydrocarbon receptor; CYP1A1, cytochrome P450 1A1; Nrf2, nuclear factor E2-related factor 2; GCLC, glutamate-cysteine ligase catalytic subunit; GCLM, glutamate-cysteine ligase modifier subunit; NQO-1, NAD(P)H dehydrogenase quinone 1; GPADH, glyceraldehyde-3phosphate dehydrogenase; MDA, malondialdehyde; ROS, reactive oxygen species; GSH/GSSG, glutathione/oxidized glutathione; GST, glutathione S-transferase