MPO and endometritis: Indole and IAld, but not IPA, treatment groups, had lower levels of MPO activity (Fig. 6H), TNF-α (Fig. 6I), and IL-1β (Fig. 6J) than ABX-Trp-treated mice, and higher levels of uterine TJ protein occludin and claudin-3 (Fig. S4B–D), which suggests that supplementation of AhR ligands rescued the protective effects of Trp on E. coli-induced endometritis.