Human Breast Milk Does Not Significantly Alter ZO-1 and Occludin Expression in Caco-2 Cells Under Basal Conditions

Document Type : Original Article

Authors
1 Research Center for Nursing and Midwifery Care, Comprehensive Research Institute for Maternal and Child Health, Department of Midwifery, School of Nursing and Midwifery, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
2 Department of Hematology, School of Allied Medicine, Iran University of Medical Sciences, Tehran, Iran
3 School of Pathology, Faculty of Medicine and Health Sciences, Universiti Sains Malaysia, Kubang Kerian, 15200 Kota Bharu, Kelantan, Malaysia
4 Department of Midwifery, TeMS.C., Islamic Azad University, Tehran, Iran
5 Student research committee, School of Nursing and Midwifery, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
Abstract
Background: Necrotizing enterocolitis (NEC) is a serious inflammatory gastrointestinal condition that impacts premature infants. Breastfeeding can lower the chances of NEC and might aid in preventing intestinal obstruction by encouraging the correct alignment of proteins such as ZO-1 and Occludin (OCLN) in the intestinal wall. This study investigated whether human breast milk alters expression of ZO-1 (TJP1) and OCLN in intestinal epithelial cells.
Methods: In this in vitro experimental study, Caco-2 cells were treated for 48 hours with 0%, 1%, or 5% (v/v) human breast milk in low-serum medium (0.5% FBS). Gene expression was measured by real-time PCR, and protein levels were confirmed by Western blot.
Results: No significant changes in ZO-1 or OCLN mRNA or protein expression were observed between treated and control groups (P > 0.05).
Conclusion: Under these experimental conditions, 1% and 5% breast milk for 48 hours did not alter ZO-1 or OCLN expression in Caco-2 cells, suggesting the protective effects of breast milk are unlikely to be mediated through these tight junction proteins. Further studies should explore alternative barrier-associated pathways, particularly under inflammatory conditions.
Keywords


Articles in Press, Accepted Manuscript
Available Online from 19 September 2026