Localization of Cyclooxygenase Isozymes in Dermal Wound Healing in Mouse

Cyclooxygenase(COX)-1 and COX-2 expression in dermal wound healing of mouse was detected by immunohistochemistry and Western blot analysis. In order to gain more information on the functional importance of COX-1 and COX-2 in dermal wound healing, we analysed COX-1 and COX-2 protein levels using the Western blotting technique. In addition, we used immunohistochemistry to determine the cellular localization of the protein products. The collected skins were rapidly frozen and kept at -70degrees Cuntil assayed. Each frozen skin was lysed with 0.5 ml of ice-cold solution. Large tissue debris and nuclear fragments were removed by two low-speed centrifugations and the resulting supernatant fraction was used for blots. The skin extracts were stored below -20degrees Cfor further experiments. By Western blotting, compared to the activity of COX-2 in normal skin, its activity was increased at days 1, 4, 8, and 12 and was maximal at 1 day after incisional wound of mouse skin whereas COX-1 was barely detectable. In normal skin, COX-1 immunostaining was observed among the basal cells of epidermis whereas COX-2 immunostaining was detected in the more differentiated, suprabasal keratinocytes. At post-incision 1-4 days, COX-2 staining was particularly prominent in the inflammatory cells, and at day 8, many macrophage-like cells were stained positively. COX-2 immunoreactive fibroblast, macrophage-like cells, and newly formed vascular endothelial cells were increased in number at 12 days after incision. These data suggest that COX-2 is constitutively expressed, just as is COX-1, in epidermis and is associated with keratinocyte differentiation. In addition, these findings support the well-established role for COX-2, the prostaglandins that they generate, as mediators of inflammatory response.

Increased Expression of Cyclooxygenase-2 Protein in Human Thyroid Tumor / 대한내분비외과학회지

PURPOSE: Thyroid tumor is one of the most common endocrine tumors, and yet little is known about its molecular process of development and progression. Cyclooxygenase (COX)-2, the inducible form of the COX enzyme for prostaglandin synthesis, is up-regulated in gastrointestinal cancers and is a key mediator of epithelial cell growth. Regular intake of aspirin or other nonsteroidal antiinflammatory drugs (NSAIDs) is associated with a decreased incidence of colorectal, esophageal, gastric, and lung cancer. We sought to determine the involvement of COX-2 in human thyroid cancer. METHODS: COX-2 protein was assayed in thyroid tissue of 64 which were inflammatory disease and benign tumor and malignant tumor with or without metastasis patients by using immunohistochemistry and Western Blot analysis. RESULTS: COX-2 protein was not expressed in normal thyroid tissue. But COX-2 protein was expressed strongly in inflammatory tissue. Expression of COX-2 was very high in both benign and malignant tumor. There is no difference in pathology and malignant potential or existence of metastasis. CONCLUSION: There was no correlation between clinicopathological characteristics of thyroid tumor and intensity of COX-2 protein expression. In addition, there was no difference of expression of COX-2 between inflammatory thyroid disease and thyroid tumor. This study indicates that COX-2 protein over expression may contribute to an early event of gastric cancer development, and it further suggests that selective inhibition of COX-2 may provide a chemopreventive effect against thyroid cancer.