ABSTRACT
The effects of dietary taurine on the experimental colitis induced by dextran sulfate sodium (DSS) in mice were evaluated. C57BL/6 female mice were given 3% DSS in drinking water for 5 d to induce acute colitis. Taurine at 2% was added to the drinking water 5 d before and during the DSS-treatment to investigate its preventive effect. Taurine supplementation significantly attenuated the weight decrease, diarrhea severity, colon shortening, and the increase in the colonic tissue myeloperoxidase activity induced by DSS. Taurine also significantly inhibited the increase in the expression of a pro-inflammatory chemokine, macrophage inflammatory protein 2 (MIP-2), but not of interleukin (IL)-1beta or tumor necrosis factor (TNF)-alpha mRNA. Furthermore, taurine significantly protected the intestinal Caco-2 cell monolayers from the damage by macrophage-like THP-1 cells in an in vitro coculture system. These results suggest that taurine prevented DSS-induced colitis partly in association with (1) its inhibitory effects on the secretion of MIP-2 from the intestinal epithelial cells and on the infiltration of such inflammatory cells as neutrophils and (2) its cytoprotective functions on the epithelial barrier from the direct toxicity of DSS and from the inflammatory cell-induced injury.
Subject(s)
Colitis/prevention & control , Dextran Sulfate/toxicity , Dietary Supplements , Taurine/pharmacology , Animals , Caco-2 Cells , Colitis/chemically induced , Colitis/metabolism , Colitis/pathology , Colon/metabolism , Colon/pathology , Cytokines/metabolism , Diarrhea/chemically induced , Diarrhea/metabolism , Diarrhea/pathology , Diarrhea/prevention & control , Disease Models, Animal , Female , Humans , Inflammation Mediators/metabolism , Mice , Neutrophils/metabolism , Neutrophils/pathologyABSTRACT
The objective of this investigation was to measure phosphorus (P) levels in the epiphyseal growth cartilage and to relate pool sizes to chondrocyte maturation and tissue mineralization. To carry out these studies, we utilized a morphochemical technique that permitted measurements of insoluble mineral phosphate, soluble inorganic phosphate (Pi), low and high molecular weight phosphorylated macromolecules and lipid P in freeze-trapped histological sections. Analysis of the sections revealed that very low levels of P are present in pre-mineralized cartilage; at the mineralization front, a large increase in Pi is correlated with mineral formation. Moreover, with calcification of the cartilage, a decrease in the concentration of low molecular weight compounds was observed. It is suggested that these latter components may provide the initial source of Pi for the development of mineral. The results of the study support the view that metabolic regulation of P pool size may be a rate-limiting factor in the mineralization of cartilage.