[Huangqin Decoction alleviates ulcerative colitis in mice by reducing endoplasmic reticulum stress]

To evaluate the therapeutic effect of Huangqin Decoction (HQD) on ulcerative colitis (UC) in mice and explore its mechanism.

Male Balb/c mice were randomly divided into normal control group, model group, mesalazine group (5-ASA, 200 mg/kg), and low-, medium-and high-dose HQD groups (2.275, 4.55 and 9.1 g/kg, respectively). With the exception of those in the normal control group, all the mice were exposed to 3% DSS solution in drinking water for 7 days to establish UC models. After treatment with the indicated drugs, the mice were assessed for colon injury and apoptosis using HE, AB-PAS and TUNEL staining, and the expression levels of inflammatory factors were detected with ELISA. Western blotting, immunohistochemistry and qRT-PCR were used to detect the changes in protein expressions associated with the intestinal chemical barrier, mechanical barrier and endoplasmic reticulum stress (ERS).

HQD treatment significantly reduced DAI score and macro score of UC mice, decreased colonic epithelial cell apoptosis, lowered expressions of IL-6, TNF-α, IL-1β and IL-8, and enhanced the expressions of MUC2 and TFF3. HQD treatment also upregulated the protein expressions of claudin-1, occludin and E-cadherin, reduced the expressions of GRP78, CHOP, caspase-12 and caspase-3, decreased the phosphorylation levels of PERK, eIF2α and IRE1α, and increased the Bcl-2/Bax ratio in the colon tissues of UC mice.

HQD inhibits colonic epithelial cell apoptosis and improves intestinal barrier function in UC mice possibly by reducing ERS mediated by the PERK and IRE1α signaling pathways.