Abstract: Purpose: To understand the function of catabolism degradation in the formation and deterioration of hypertrophic scar. Method: The study was carried out clinically, on animal model and cultured fibroblast cell. The investigation was conducted with naked eye, microscope, situ hybridization, dot blot hybridization, TUNEL and immunohistochemistry. Result:①The hypertrophic scar grew up very slow but might be eliminated 1/3 to 2/3 within one month with different chemical intervention. ②The synthesis of collagen in hypertrophic scar increased a little, but it's degradation decreased much more. ③The collagenase MMP-1 could destroy the collagen after local injection into the hypertrophic scar, it was proved by light and electromicroscope. ④The expression of MMP-1 Mrna increased a little in hypertrophic scar, but MMP-1 in the scar really decreased in quantity and activity. ⑤Ch-4-S increased significantly in hypertrophic scar, it wrapped up the collagen fibrils and blocked its contact with and avoided its catabolism by MMP-1.TIMP increased in hypertrophic scar and depressed the activity of MMP-1. ⑦The expression of TGF-β increased significantly. It positively related with the expression of TIMP and negatively related with the apototic phenomena in hypertrophic scar. The fibroblast in hypertrophic scar was rich and active, but its proliferation was not elevated and apotosis was delayed. Conclusion: ①The delay of apotosis of fibroblast, the wrapping of collagen by Ch-4-S, the reduction of collagenase in quantity and activity together made the abolition of collagen decreased and might be primary for the formation of hypertrophic scar. ②Accelerating the apotosis of fibroblast and catabolism of collagen might be an easy and rapid way for prevention and treatment of hypertrophic scar.

Key words: hypertrophic scar, collagen, catabolism degradation