Abstract: Objective To investigate the effect of allogeneic nanofat combined with platelet-rich plasma (PRP) for treatment of pressure injury wounds in rats. Methods Forty SD rat models with pressure injury wounds were randomly divided into 4 groups (n=10) for treatment with nanofat, PRP (platelet count about 6.2 times that of normal whole blood), nanofat combined with PRP, or PBS only (control group).Wound healing was observed on days 1, 3, 5, 7, 10 and 14 and wound healing rate was calculated. On days 5, 10 and 14, tissue samples were taken from the wounds for HE staining, Masson staining, immunohistochemistry, and Western blotting to observe inflammatory cell infiltration, collagen formation, deposition and arrangement, angiogenesis, inflammatory factor expression and VEGF expression in the wounds. Results The combined treatment with nanofat and PRP achieved the highest wound healing rates at all the time points of observation (P<0.05), enhanced inflammatory cell infiltration on day 5, and accelerated dermal and epidermal growth compared with the other treatments (P<0.05). The combined treatment also more effectively promoted collagen expression and its regular arrangement (P<0.05) and enhanced angiogenesis in the wounds than nanofat and PRP alone, without significant difference between the latter two treatments (P>0.05). Immunohistochemistry and Western blotting showed that the expressions of MCP-1 and VEGF in the wounds were the highest in the combined treatment group (P<0.05) and were higher in nanofat and PRP treatment groups than in the control group (P<0.05). Conclusion Nanofat combined with PRP can significantly promote healing of pressure injury wounds in rats, and their synergistic effect sheds light on a new strategy for treatment of pressure injury wounds.

Key words: pressure injury; nanofat; platelet rich plasma; wound healing