Background: The use of acellular dermal matrix on chronic diabetic wounds in clinical practice is hindered by its high cost and difficulty in application. We aimed to acquire experimental evidence on the effect of morphologically transformed acellular dermal matrix on chronic diabetic wounds and investigate how this transformation affects the wound healing mechanism. Materials and methods:We developed a new chronic wound model that resembles a diabetic chronic wound as it involves an open wound with partial calvarial bone exposure in diabetic rats. According to treatment materials, rats were assigned into the CONTROL, ADM, and PASTE groups. The wound healing period was subdivided into T1 and T2 (postoperative days 14 and 30, respectively). Three-staged analyses were performed using 3D camera, histological analysis, and real-time quantitative polymerase chain reaction. Results:The morphologically transformed acellular dermal matrix showed a compatible treatment rate in the total wound and more rapidly reduced the initial bone exposure area.In the PASTE group, collagen scaffold appeared at a later period and expression levels of epidermal growth factor and epidermal growth factor receptor increased. Conclusions:The transformation of acellular dermal matrix into the pulverized form is thought to contribute to its non-inferior therapeutic effect compared with normal acellular dermal matrix. With respect to the mechanism, the pulverized form reduced the bone exposure area in the early stage and provided a collagen scaffold at a later period. An in-Abbreviations: ADM, acellular dermal matrix; q-PCR, quantitative polymerase chain reaction; H&E, hematoxylin and eosin; MT, Goldner's Masson trichrome; vWF, von Willebrand factor; TGF-1 β, transforming growth factor-1 β; VEGF-α, vascular endothelial growth factor-α; EGF, epidermal growth factor; EGFR, epidermal growth factor receptor; GAPDH, glyceraldehyde 3-phosphate dehydrogenase.