Fecal Microbiota Transplantation Repairs Intestinal Mucosal Barrier Injury in Mice with Ulcerative Colitis

Abstract

This study aimed to explore the effects of fecal microbiota transplantation (FMT) on intestinal mucosal barrier injury in mice with ulcerative colitis (UC) and to elucidate the underlying mechanisms. Dextran sodium sulfate (DSS) was administered to develop the UC mouse model. Next, the experiment was divided into a normal control group, a DSS model group, a DSS+5-amino acid salicylic acid (5-ASA) group, and a DSS+FMT group. Hematoxylin–eosin staining was used to detect pathological changes; transmission electron microscopy was used to evaluate structural changes of intestinal mucosa; enzyme-linked immunosorbent assay (ELSIA) was used to detect endotoxins; and western blotting was used to detect the expression of zonula occludens-1 (ZO-1). In the control group, the intestinal mucosa and microvilli were intact, epithelial cells were closely connected, and the intercellular space was narrow. By contrast, focal intestinal barrier defects, including shallow ulcer, local inflammatory cell infiltration, hyperplasia of connective tissue, and loss of gland structure were observed in the model group. These abnormal morphological and structural changes were ameliorated by 5-ASA and FMT. Compared with the control group, the endotoxin content increased significantly, and the ZO-1 protein expression decreased significantly in the model group (P < 0.05). By contrast, the endotoxin level decreased significantly, and the ZO-1 protein expression increased significantly in the 5-ASA group and FMT group compared with that of the model group (P < 0.05). FMT ameliorates UC by repairing the intestinal barrier function, which is likely involved in upregulating ZO-1 expression.