Effects of carrageenan on cell permeability, cytotoxicity, and cytokine gene expression in human intestinal and hepatic cell lines

• Published in: Food and chemical toxicology Vol. 96; pp. 1 - 10
• Main Authors: McKim, James M., Baas, Heidi, Rice, Gabriel P., Willoughby, Jamin A., Weiner, Myra L., Blakemore, William
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01-10-2016
• Subjects: Apoptosis - drug effects; Blotting, Western; Carrageenan; Carrageenan - pharmacology; Cell Membrane Permeability - drug effects; Cell Proliferation - drug effects; Cytokines - genetics; Cytokines - metabolism; Gene Expression Regulation, Neoplastic - drug effects; Humans; Inflammation; Inflammation Mediators - metabolism; Intestinal Neoplasms - drug therapy; Intestinal Neoplasms - genetics; Intestinal Neoplasms - metabolism; Intestinal Neoplasms - pathology; Intestine; In vitro; Liver; Liver Neoplasms - drug therapy; Liver Neoplasms - genetics; Liver Neoplasms - metabolism; Liver Neoplasms - pathology; Real-Time Polymerase Chain Reaction; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger - genetics; Toll-like receptor 4; Tumor Cells, Cultured; In vitro; Inflammation; Carrageenan; Intestine; Liver; Toll-like receptor 4
• ISSN: 0278-6915; 1873-6351
• DOI: 10.1016/j.fct.2016.07.006

Carrageenan (CGN) is a common food additive used for its gelling and thickening properties. The present study was done to evaluate intestinal permeability, cytotoxicity, and CGN-mediated induction of proinflammatory cytokines. A standard Caco-2 absorption model showed no CGN permeability or cytotoxicity at concentrations of 100, 500, and 1000 μg/mL. In two human intestinal cell lines (HT-29 and HCT-8) CGN (0.1, 1.0, and 10.0 μg/mL) did not induce IL-8, IL-6, or MCP-1 (CCL2) or produce cellular toxicity after 24 h. The TLR4 agonist LPS produced weak induction of IL-8 in HT-29 cells and no induction in HCT-8 cells. The effects of κ-CGN (0.1, 1.0, and 10 μg/mL) on cellular oxidative stress was assessed in HT-29 cells using CM-H2DCFDA as the probe. No effect on oxidative stress was observed after 24 h. In the human (HepG2) liver cell line, ʎ-CGN (0.1, 1.0, 10.0 and 100.0 μg/mL) had no effect on the expression of IL-8, IL-6, or MCP-1 (CCL2) after 24 h. In conclusion, CGN was not absorbed, and was not cytotoxic. It did not induce oxidative stress, and did not induce proinflammatory proteins.
•Three common forms of the food additive carrageenan were tested in vitro.•The carrageenan tested were subjected to advanced identity and purity testing.•Carrageenan was evaluated in three human intestinal cell lines.•Endpoints included permeability, cytotoxicity, and induction of cytokines.•Carrageenan was negative in all endpoints evaluated.