EXPERIMENTAL CUTANEOUS CALCINOSIS - A HISTOPATHOLOGIC AND HISTOCHEMICAL STUDY

[摘要] Cutaneous calcinosis was induced in rats by sensitization with oral dihydrotrachys-terol (DHT) and the use of subcutaneous iron dextran, subcutaneous egg white, or plucking. The DHT treated controls did not show significant abnormal change except for a possible increase in the number of fibrocytes and mast cells. Iron dextran and egg white treated controls showed a definite increase in the number of dermal fibrocytes and mast cells, a moderate number of inflammatory cells in the subcutaneous tissue but rarely extending into the dermis, and increased amounts of material with histochemical properties of hyaluronic acid located in the extracellular interfibrillar ground substance. Sections from rats following iron dextran injections showed intracellular and extracellular iron extending from the middermis to the subcutaneous tissue. Iron was contained in fibrocytic cells but not within mast cells. In animals given DHT and iron dextran, egg white, or plucked, initial calcification usually occurred within 24 to 48 hours. Alkaline phosphatase positive fibroblast-like cells appeared prior to initial calcification but were not always located immediately adjacent to initially calcified sites. These cells were not seen in sections from control animals or in normal skin. The origin of the alkaline phosphatase positive cells was not definitely determined but may be from capillary en-dothelium or pre-existing dermal fibrocytes. Alkaline phosphatase may act by destroying polyphosphate inhibitors normally present in the tissues. Initial sites of calcification appeared to be related to areas rich in acid mucopolysaccharides or in some instances, collagen fibers. Hyaluronic acid in extracellular spaces, collagen fibers (perhaps containing chondroitin sulfate B) and/or acid mucopolysaccharides associated with hair follicles appeared to act as matrix substances.