Abstract: BACKGROUND: Promoting skin wound healing is a huge challenge facing global public health. To promote faster and higher-quality wound healing, it is necessary to explore more advantageous dressings to address this problem.
OBJECTIVE: To investigate the hemostatic properties of acellular dermal matrix hydrogel and its effect on skin wound healing. 
METHODS: (1) Acellular dermal matrix hydrogel was prepared, and the differences in microscopic morphology and main components between it and acellular dermal matrix were analyzed. (2) Acellular dermal matrix hydrogel and chitosan hydrogel were used to cover the femoral artery puncture site of rats, and the bleeding quality and coagulation time were recorded. Acellular dermal matrix hydrogel and chitosan hydrogel were mixed with rat anticoagulated blood, and the coagulation index within 30 minutes was detected. (3) A full-thickness skin defect model with a diameter of 12 mm was made on the back of 18 SD rats, and they were randomly divided into 3 groups, with 6 rats in each group: the model group used PBS to clean the wound, and the control group and the experimental group used chitosan hydrogel and acellular dermal matrix hydrogel to cover the wound, respectively. The hydrogel dressing was changed every day, and the treatment was continued for 14 days, and the wound healing was observed. On day 3 after modeling, immunofluorescence staining of inducible nitric oxide synthase (M1 macrophages) and CD206 (M2 macrophages) was performed on the wound surface. On day 14 after modeling, hematoxylin-eosin staining, Masson staining, and CD31 immunohistochemical staining were performed on the wound surface.
RESULTS AND CONCLUSION: (1) Scanning electron microscopy revealed that the acellular dermal matrix hydrogel had a porous structure, and the Fourier transform infrared spectrum showed that it had the same main components as the acellular dermal matrix. (2) Both acellular dermal matrix hydrogel and chitosan hydrogel had obvious hemostatic ability in vivo. In the in vitro coagulation experiments, the coagulation index of acellular dermal matrix hydrogel was significantly higher than that of chitosan hydrogel. (3) In the rat skin full-thickness defect model, both acellular dermal matrix hydrogel and chitosan hydrogel could improve the wound healing rate. Hematoxylin-eosin and Masson staining results showed that acellular dermal matrix hydrogel could reduce the infiltration of inflammatory cells in the center of the wound. Both acellular dermal matrix hydrogel and chitosan hydrogel could decrease scar width and increase collagen deposition rate. CD31 immunohistochemical staining results showed that both hydrogels could promote angiogenesis in the wound site. Immunofluorescence staining results showed that both hydrogels could reduce the proportion of M1 macrophages and increase the proportion of M2 macrophages, and the effect of acellular dermal matrix hydrogel was stronger than that of chitosan hydrogel. (4) The results show that the acellular dermal matrix hydrogel has good hemostatic properties and the ability to promote wound healing.

Key words: wound healing, acellular derma, matrix, chitosan, hydrogel, tissue restoration, hemostasis, engineered skin materials