Abstract
Alpha (α)-tocopherol is a major component of dietary vitamin E. Despite being one of the most widely used food supplements in both animals and humans, its role in intestinal functions remains unknown. We were able to examine and accurately demonstrate its permeability effect in vitro and its differentiated effect on tight junction expression in different segments of the intestine in vivo using cultured intestinal porcine epithelial cell line (IPEC-J2) and piglets. A cultured IPEC-J2 demonstrated that α-tocopherol upregulated the expression of tight junction proteins and improved their integrity, with a maximum effect at concentrations ranging from 20 to 40 μmol/L. In vivo data from weaned pigs fed different doses of α-tocopherol for 2 weeks revealed that α-tocopherol effectively increases the expression of tight junction proteins in all sections of the intestinal mucosa, with the highest effect on the duodenum at an optimum dose of 20-50 mg/kg. In contrast, α-tocopherol did not affect intestinal inflammation. These findings suggest that α-tocopherol maintains intestinal integrity and increases the expression of tight junction proteins both in vitro and in vivo.