No abstract

Wound healing is a dynamic process, and a variety of growth factors have a significant impact on the process. Although the WNT family has a multitude of effects on the state of various physiological pathways, the expression and role of WNT in wounded tissue have remained an enigma. The aim of this study was to assess the expression and localization of WNTs in a murine model of wound healing. RNA isolated from fullthickness cutaneous wounds from day 1 to day 21 postwounding were subjected to reverse transcriptionpolymerase chain reaction, and expression of WNT3, 4, 5a, and 10b were observed. Immunohistochemistry localized WNT10b to regenerating epithelial cells on day 1 and 3, and WNT4 on day 3 and 5. WNT4 also reacted with fibroblast-like cells beneath the epithelium. The cytoplasmic staining of b-catenin, a WNT signaling molecule, in the epithelial cells indicates an activation of the WNT signaling pathway. Among target genes downstream of the pathway, matrix metalloproteinases (MMPs) degrade and remodel the extracellular matrix during wound healing. Gelatin zymography showed that MMP9 was expressed from day 1 to day 5. MMP-2 was continuously expressed, but maximally up-regulated at day 5. Activation of MMP-2 coincided with expression of membrane-type 1 MMP, suggesting an involvement of WNTs in this proteolytic cascade. Therefore, WNTs may contribute to the process of wound healing in a spatiotemporal manner. (WOUND REP REG 2005;13:491-497) ECM Extracellular matrix GAPDH Glyceraldehyde 3-phosphate dehydrogenase MMP Matrix metalloproteinase MT1-MMP Membrane type 1-MMP RT-PCR Reverse transcription-polymerase chain reactionWound healing is a dynamic and interactive process requiring the collaboration of effector molecules from many different tissues and cell lineages. The behavior of each component contributes cell types during the phases of proliferation, migration, matrix synthesis, and contraction, as well as growth factor and matrix signals present at a wound site. Numerous studies have indicated that the combined actions of various growth factors, properly timed, are indispensable for complete wound closure and new tissue formation. 1,2 Although the use of recombinant growth factors could be a next avenue to accelerate the wound healing process, clinical application of these factors has just begun. 2 Understanding detailed molecular mechanisms for the processes of wound repair is a prerequisite for the development of novel therapeutic strategies. The WNT family of genes has been identified as an oncogenic gene family that transmits its signals through binding of the translated protein products to cell surface receptors. WNT members are classified into two groups, canonical and other, according to their downstream signaling pathway. 3 WNT3 and WNT10b activate the canonical signaling pathway by inhibiting the kinase activity of glycogen synthase kinase 3-b and increasing the cytoplasimc pool of free b-catenin. 4,5 WNT5a stimulates G protein-dependent Ca þþ signaling machinery. 6 Downstream signaling

The aim of this study was to evaluate the physico-mechanical properties of a new cavity base material containing mineral trioxide aggregate, LA-T1, prototyped by Neo Dental Chemical Products for indirect restoration. Three base materials, LA-T1, Cavios (CAV, Neo Dental Chemical Products), and Bulk Base Hard (BBH, Sun Medical), were examined. The depth of cure, microshear bond strength with a resin-based luting cement, and the compressive strength of these materials were investigated. The depth of cure of LA-T1 was similar to that of CAV, while the depth of cure of BBH was above the measurement limit. The distance from the base material to the light source, 0 mm and 4 mm, did not significantly affect the depth of cure of all materials. The microshear bond strength of LA-T1 bonded to a resin-based luting cement was slightly higher than that of CAV and similar to that of BBH, both of which were bonded to the same luting cement under the same conditions. The compressive strength of LA-T1 was similar to that of CAV but less than that of BBH. The results of this study indicate that LA-T1 has properties that are similar to those of CAV and thus can be clinically applied.