ABSTRACT
Numerous treatments have been used in the management of corneal chemical burns; however, no optimal treatment for corneal chemical burns currently exists. The present study investigated the effects of topical chondrocyte-derived extracellular matrix (CD-ECM) treatment on corneal wound healing, using an alkali burn mouse model. Topical treatment with CD-ECM was shown to reduce corneal opacity following an alkali burn. A histological examination observed the presence of regenerated epithelial cells and a small number of inflammatory cells in the corneas of CD-ECM-treated mice. The majority of the inflammatory cells present in the corneas of the phosphate-buffered saline (PBS)-treated mice were neutrophils that expressed matrix metalloproteinase (MMP)-9. The amount of neutrophils was significantly reduced in the corneas of the CD-ECM-treated mice. Furthermore, the expression levels of interleukin (IL)-8 were significantly reduced in the CD-ECM treatment group, but not in the mice that received the PBS treatment. The results of the present study indicate that CD-ECM treatment may accelerate wound healing in a model of alkali burn-induced corneal injury. The therapeutic mechanism may be associated with accelerated reepithelialization and reduced recruitment of MMP-9-expressing neutrophils, through inhibiting the production of IL-8.
Subject(s)
Burns, Chemical , Chondrocytes , Corneal Injuries/chemically induced , Extracellular Matrix , Eye Burns/chemically induced , Wound Healing/drug effects , Administration, Topical , Animals , Corneal Injuries/drug therapy , Disease Models, Animal , Eye Burns/drug therapy , Female , Interleukin-8/biosynthesis , Matrix Metalloproteinase 9 , Mice , Neutrophil Infiltration , Neutrophils/immunology , Neutrophils/metabolism , Neutrophils/pathologyABSTRACT
The generation of tryptophan (Trp) metabolites by indoleamine 2,3-dioxygenase (IDO) is an effective mechanism for T cell suppression. However, the effect of Trp metabolites on dendritic cells (DCs) remains unclear. Here, we investigated whether the tryptophan metabolite 3-hydroxyanthranilic acid (3-HAA) directly inhibits DC activation and is responsible for T cell suppression. We found that 3-HAA treatment significantly reduced IL-12, IL-6, and TNF-α production in bone marrow-derived DCs (BMDCs) stimulated with LPS. Maturation markers CD40, CD80, CD86, and I-A were also significantly reduced. Moreover, treatment with 3-HAA decreased the ability of DCs to stimulate T cell activation and differentiation in vitro and in vivo. Finally, we observed that phospho-JNK and phospho-38 levels were reduced in 3-HAA-treated DC2.4 cells and BMDCs. These results suggest that the tryptophan metabolite 3-HAA suppresses T cell responses by inhibiting DC activation.
