TGF-β2, EGF and FGF21 influence the suckling rat intestinal maturation

•The intestinal barrier function is still in formation in early life, and it can be assessed in suckling rats between 10 and 14 days of life.•During the suckling period, the supplementation with TGF-β2, EGF and FGF21 showed important signs of intestinal maturation and barrier function.•TGF-β2, EGF and FGF21, growth factors present in breast milk, play a modulatory role in the IEL composition during suckling. Some of the growth factors present in breast milk, such as transforming growth factor-β (TGF-β), epidermal growth factor (EGF) and fibroblast growth factor 21 (FGF21), play important roles in the development of the intestinal tract. The aim of this study was to determine the effect of a supplementation with TGF-β2, EGF and FGF21 on suckling rats intestinal maturation. For this purpose, Wistar rats were supplemented daily with TGF-β2, EGF or FGF21 throughout the suckling period. We evaluated the functionality of the intestinal epithelial barrier through an in vivo dextran permeability assay, and by a histomorphometric and immunohistochemical study. In addition, the intestinal gene expression of tight junction-associated proteins, mucins, toll-like receptors, and maturation markers was analyzed. Moreover, the intraepithelial lymphocyte (IEL) phenotypical composition was established. During the suckling period, the supplementation with TGF-β2, EGF and FGF21 showed important signs of intestinal maturation. These results suggest that these molecules, present in breast milk, play a modulatory role in the maturation of the intestinal barrier function and the IEL composition during the suckling period.