Abstract:To investigate whether various dosages of marketed food-grade κ-carrageenan could induce colitis in the organisms, the subtype and molecular weight of purchased carrageenan sample were detected. 72 6-week-old C57BL/6J mice were randomly divided into 6 groups and fed the normal diet (NC), the normal diet mixed with the dosages of 0.05% (0.05% CGN), 0.5% (0.5% CGN), 1% (1% CGN), 2.5% (2.5% CGN) and 5% (5% CGN) of the carrageenan sample for six weeks, respectively. The related colitis markers of mice were measured after sacrifice. The characteristic analysis of carrageenan indicated that the sample belonged to κ type food-grade carrageenan. The animal experiment showed that different dosages of carrageenan intervention had no significant effects on the thymus index, spleen index, colon microstructure and length, and release of prostaglandin E2 (PGE2) in colon (p>0.05). The protein expression of tumor necrosis factor-α (TNF-α) and the activity of myeloperoxidase (MPO) in the colon of 0.05% CGN and 2.5% CGN group mice respectively decreased by 63.14% and 29.50%, compared to the control group (p<0.05, p<0.01). There was no significant difference between the other dosage groups and the control group (p>0.05). The protein expression of Toll-like receptor 4 (TLR4) in colonic epithelium of mice in 1% CGN group was higher than that in control group (66.67%, p<0.05) and there was no significant difference between the other carrageenan intervention groups and the control group (p>0.05). The research results suggested that supplementation of 0.05%~5% food-grade κ-carrageenan in diet had no colitis effect for mice. The results show that the adults who consume carrageenan-processed-food daily are not at risk for colitis.
