Histological analysis of liver and intestinal tissues

For hematoxylin and eosin (H&E) staining, paraformalin-fixed paraffin tissue sections were used to evaluate the characteristics of liver and intestinal tissues regarding histological changes and fibrosis. The immunohistochemistry procedure was performed as described previously [27 (link)], including the following primary antibodies CHOP, GRP78, PDI, and XBP-1 (sc-7351, sc-166490, sc-74551, and sc-8015, Santa Cruz Biotech, USA). The positive areas of CHOP, GRP78, PDI, and XBP-1 were recorded. For immunofluorescence, the tissue sections were blocked with 10% normal donkey serum for 1 h at 25° C in PBS and then incubated overnight with primary antibodies against claudin-1, occludin, and ZO-1 (sc-166338, sc-133256, sc-33725, Santa Cruz Biotech, USA) and P-gp (ab261736, Abcam) at 4° C. The nuclei were stained with Hoechst 33258 (0.25 l g/mL) dye. All fluorescence images were captured on a Nikon ECLIPSE Ti microscope.