In Vitro Study on the Absorption and Transportation of Ovotransferrin Using Rat Intestinal Epithelial Cells (IEC-6)

Abstract

Ovotransferrin (OTF) is an iron-binding protein present in eggs and can deliver iron to cells. However, the absorption and transportation of OTFthrough the intestinalcells remained unknown. The objectives of this study wereto determine the absorption and transportation mechanism of OTFthrough rat epithelial cells (IEC-6). The in vitrotransportation of OTFwas detected by SDS-PAGEand visualized by immunohistochemistry experiment. Also, the uptake of OTFinto IEC-6 cells; as well as the amount of transported OTFwere quantifiedby ELISA method. Microscopic images clearly showed the accumulation of OTF on the cells membraneand provided the evidence of OTF-receptors’ presence on the plasma membrane. Also, OTF was detected within the cytoplasm of IEC-6 cells, revealed that it was internalized by receptor-mediated endocytosis. ELISA results demonstrated that OTF can be taken up by IEC-6 cells as an intact protein from the apical surface and transported to the basolateral surface through trans-epithelial exocytosis mechanism. The maximum internalization and exocytosis were observed at 90 min. These processes were time and concentration dependent. Therefore, it is concluded that absorption and trans-epithelial transportation of OTF accomplished by receptor-mediated transcytosis in intestinal epithelial cells.