A: Intestinal resection and anastomosis surgical procedure: red arrow is end of intestinal incision; blue arrow is anastomotic intestinal tube; yellow arrow is mesenteric suture. B: Schematic of suture methods for various tissues and organs during intestinal resection and anastomosis. C: Schematic of biopsy preservation. D: Intestinal villus and fundamental structure observed by H&E and scanning electron microscope, arrow shows small intestine microvilli. E: Subsets and proportion of epithelial lymphocytes and lamina propria lymphocytes analyzed by flow cytometry. F: Structure of intestinal villi after EDTA digestion. G: Antigenic epitopes observed by immunofluorescence staining. H: RNA quality analysis.