Hypertrophic scar, occurred from the skin injury or surgical operation causes esthetic, psychologic, and functional problems to the patients and surgeon. The drug of choice for the treatment of hypertrophic scar is steroids.
The purpose of this study was to evaluate the effects of several kinds of steroid injection on the hypertrophic scar in the- rabbit model.
Adult male white rabbits, weighing about 2.5 kg. were used. After three full-thickness wounding over the ventral surface of each ear, either saline (control group), or triamoonclone(0.8mg), dexamethasone(0.1mg), and prednisolone(0.8mg) was injected on day 16. Rabbits were sacrificed on 1,_ 2, 3, 4, and 8 weeks after injection, and the specimens were retrieved en bloc, Histologic and histomorphometric examinations of tissue samples were done. The results obtained were as follows :
In cor*rol group, cartilage proliferation and soft tissue hypertrophy were seen on 1 week and 2 weeks after saline injection. Collagen fibers were thickened in diameter, and arranged in irregular manner. After 3 weeks, cartilage proliferation was markedly decreased. Irregular collagen fibers and soft tissue thickening were also observed. After 4 and 8 weeks, soft tissues were consist of loose connective tissue, and still thickened. In experimental groups, collagen fiber thickness were arranged in somewhat irregular manner, and small amount of blood vessel proliferation were observed in 1, 2, and 3 weeks after injection. After 4 weeks, blood vessels and nflammatory cells were decreased, and collagen fibers were arranged in parallel manner. In 8 weeks group, small amount of loose connective tissues were observed. After 2 weeks of injection, hypertrophic index of experimental groups were significantly more decreased than control group. In experimental group, dexamethasone seemed more potent compared with triamcinolone and prednisolone.
These results suggest that hypertrophic scar was markedly decreased after steroid injection and triamcinolone, dexamethasone, and prednisolone are effective for treatment of hypertrophic scar.
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