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

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 mu/mL. In two human intestinal cell lines (HT-29 and HCT-8) CGN (0.1, 1.0, and 10.0 mu g/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 kappa-CGN (0.1, 1.0, and 10 mu g/mL) on cellular oxidative stress was assessed in HT-29 cells using CM-H(2)DCFDA as the probe. No effect on oxidative stress was observed after 24 h. In the human (HepG2) liver cell line, lambda-CGN (0.1,1.0,10.0 and 100.0 mu g/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. (C) 2016 The Authors. Published by Elsevier Ltd.