Background: Decellularized extracellular matrix (ECM) scaffold can promote wound healing by providing an appropriate substrate for cell attachment, stimulation of angiogenesis, and formation of granulation tissue in the wound area.
Small intestinal submucosa (SIS) contains various constituents similar to dermal ECM, such as collagen, elastin, glycosaminoglycans, proteoglycans, and growth factors that play important roles in wound healing. Here, we developed a biological skin substitute based on decellularized SIS for skin wound repair. Methods: Bovine SIS was extracted and decellularized using an optimized protocol. Total DNA content was quantified in samples of native and decellularized SIS. Moreover, histological evaluation and quantification of collagen and sulfated GAG were performed in both native and decellularized SIS. The formation of tri-layer (۳L) SIS was performed by vacuum pressing and lyophilization. A uniaxial tensile test was applied for the mechanical analysis of the samples. The effectiveness of the SIS scaffold as a skin substitute was evaluated in a full-thickness critical-sized wound defect in a rat model. The experimental groups included: group I (non-treated as control), group II (۱L SIS), and group III (۳L SIS).
Wound healing of all groups was examined and compared histopathologically on day ۲۸ post-operation. Results:
Decellularization procedure resulted in significant removal of DNA as measured by quantification of DNA contents. Histological evaluation and quantification of collagen and sulfated GAG demonstrated that the ECM composition was almost preserved after decellularization procedure. Compared to the original single-layer (۱L) SIS, ۳L SIS has stronger mechanical properties and is more slowly degraded in the wound area. The in vivo results showed that the ۳L SIS scaffold had a faster healing rate, as it accelerated wound contraction and re-epithelialization, enhanced collagen deposition, and promoted skin appendage rejuvenation, when compared with the two other groups. Conclusion: Decellularized SIS scaffold can introduce a natural substrate with tunable thickness and mechanical strength that supports the wound healing process. It can be recognized as a promising skin substitute for the management of a wide array of acute and chronic wounds.
