β-Carotene improves intestinal barrier function by modulating proinflammatory cytokines and improving antioxidant capacity in β-lactoglobulin-sensitized mice

Abstract

Increased intestinal permeability due to barrier dysfunction is supposed to cause several gastrointestinal diseases. We have previously demonstrated that a single β-carotene (BC) dose protects against increase in anaphylactic response in β-lactoglobulin (BLG)-sensitized mice with no effect on the epithelial permeability and weak recovery of villi length. Utilizing the same murine ex vivo intestinal model, the aim of this study was to investigate the effect of different BC doses on BLG-mediated intestinal epithelial barrier disturbances. Jejunum was harvested from BLG-sensitized mice pretreated with either one of three different doses of BC (5, 10 and 20 mg/ kg body weight) and mounted on Ussing Chambers. Transepithelial electrical resistance (TER) and short-circuit current (Isc) were recorded as indicators of intestinal epithelial barrier function. Histopathological analysis of the intestine was carried out for the control and experimental mice. TNF-α and IL-6 levels were determined in serum using ELISA, and the analysis of antioxidant activity was performed for reduced glutathione (GSH) and thiobarbituric acid reactive substances (TBARS). BC was capable of enhancing the intestinal barrier function, as indicated by the increased TER and the decreased Isc. Intestinal damage characterized by the shortening of villi and infiltration of intestinal lymphocytes was significantly reversed by BC pretreatment. Such effects of BC were accompanied by a reduction in the levels of IL-6 and TBARS and an increase of GSH. TNF-α levels were reduced only at the lowest BC dose. These findings may encourage the use of BC-based therapies for controlling the breakdown of the intestinal barrier in vivo.