Abstract: Objective To establish hypertrophic scar(HS)model on severe combined immunodeficiency(SCID)mice and investigate the feasibility. Methods Human split-thickness skin graft was transplanted onto the dorsum of SCID mice, the harvested xenograft was then assessed and given biopsy for histology by hematoxylin & eosin (HE) or Masson's trichrome staining 2 and 4 weeks after operation, and hydroxyproline quantification by colorimetry 4 weeks after operation. RT-PCR analysis was also performed to identify mRNA levels of transforming growth factor-β1(TGF-β1)and connective tissue growth factor (CTGF)2 and 4 weeks after operation. Results The xenograft showed a characteristic of human HS including a red, firm, elevated appearance, and dermal thickness, changed adnexal structures, hypervascularization, thinner collagen fibrils and disorganization of them. The content of hydroxyproline in experimental group increased significantly compared to the control group 4 weeks after operation(P<0.05).Moreover,RT-PCR showed significantly elevated mRNA levels for both TGF-β1 and CTGF in experimental group 2 and 4 weeks after operation (P<0.01). Conclusion This animal model has intrinsic properties that closely resemble HS formation as seen in humans, which shares additional merits of simple operation and flexible controllability and therefore can be expected to play a critic role in the research of human HS.

Key words: Hypertrophic scar, Animal model, Inflammation, Pathological fibrosis