ALP (alkaline phosphatase) is a membrane-bound metalloenzyme that is expressed in osteoblasts, hepatocytes, lung, kidney, endothelial cells, leukocytes and other cells. Normal soft tissue and skin show little tissue nonspecific ALP (TN-AP). However, scar tissue contains high levels of TN-AP activity, and in fact, TN-AP is expressed intensely in regenerating connective tissue after the wounding.
The purpose of this study was to evaluate the change of ALP expression in hypertrophic scar model in rabbits and the effect´ of triamcinonolone on ALP expression. Adult male New Zealand white rabbits, weighing about 2.5 kg, were used. After full-thickeness wounding over the ventral surface of each ear, either saline(control ear) or triamcinolon(contralateral ear) was injected on day 1.6. Rabbits were sacrificed on day 3, 7, 15, 17, 19, 23, and the specimens were retrieved en bloc. Histologic and immunohistochemical examinations of tissue samples were done. The results obtained were as follows :
On day 3, ALP reaction was observed on fibroblasts and inflammatory cells in wound margin. On clay 7, ALP reaction was more intense! than day 3 in capillaries, inflammtory cells, and fibroblasts behind newly formed epithelium. On day 15, ALP reaction was lessened in both groups and appeared mainly in subepidermal capillary network. Since day 17, ALP reaction was lessened in both groups and weaker in triamcinolone-injected group than in saline-injected group.
These results suggest that ALP reaction isn´t increased in triamcinolone-injected scar and triancinolone reduces scar not by increasing TN-AP expression but other mechanism.
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