Intestinal mucosal barrier function and epithelial–mesenchymal transition (EMT) are also two important mechanisms of intestinal inflammation, fibrosis, and stenosis.10 We examined the effects of Smad3 on the proliferation and migration of intestinal epithelial cells, on the expression of tight junction protein zonula occludens-1 (ZO-1), and on EMT to explore the mechanism of Smad3 affecting postnecrotizing enterocolitis stricture. The gene discussed is SMAD3; the disease is enterocolitis.