Culture Optimization of the IPEC-J2 Piglet Jejunum Cell Line for Applications in Infant Nutrition Research

The intestinal porcine epithelial cell line (IPEC-J2) is a nontransformed jejunal model derived from unsuckled piglets. It is increasingly used in gut physiology research, yet its application to nutrient absorption remains underexplored. Four media types were assessed for their ability to support IPEC-J2 barrier maturation and permeability: Dulbecco's modified Eagle medium/Ham's F-12 with 10% fetal bovine serum (FBS10), 10% porcine serum (PS10), 5% porcine serum (PS5) supplemented with Wnt3a-R-spondin-Noggin conditioned medium (PS5+L-WRN), and PS5 with epidermal growth factor and insulin-transferrin-selenium (PS5+EGF+ITS). Culture medium influenced epithelial phenotype, with more than a 30-fold range in transepithelial electrical resistance (TEER), which plateaued by day 12. PS10 supported a balanced profile, characterized by intermediate TEER (2395.00 ± 485.51 Ω × cm²), lowest lactulose and mannitol permeability (p < 0.05), high lactate dehydrogenase activity (p < 0.05 vs. PS5+L-WRN and FBS10), enhanced membrane localization of tight junction proteins (p < 0.05 vs. PS5+EGF+ITS), and reduced fibroblast marker S100A4 (p < 0.05 vs. PS5+EGF+ITS). Treatment with digested infant milk formula did not compromise barrier integrity in PS10-cultured IPEC-J2 monolayers and enabled transport of free amino acids to the basolateral compartment. These findings support IPEC-J2 as an alternative to Caco-2 cells for applications in infant nutrition research in vitro.