Design of a matrix for cultured dermal substitute suitable for simultaneous transplantation with auto-skin graft: evaluation in animal test.

This study focused on the design of a matrix for a cultured dermal substitute (CDS). Two types of cross-linked spongy matrix were designed. The weight ratio of hyaluronic acid (HA) to a cross-linking agent was adjusted to 5:1 (c-5) or 15:1 (c-15). Each HA spongy matrix was combined with collagen (Col) gel, forming 4 groups: Group I, c-5 sponge and Col gel; Group II, c-5 sponge and Col gel with human fibroblasts; Group III, c-15 sponge and Col gel; and Group IV, c-15 sponge and Col gel with human fibroblasts. The physical properties of the matrix depend on the cross-linking conditions. In animal tests using T-cell-deficient F344 rats, materials from Groups I-IV were transplanted onto a full-thickness skin defect, followed by auto-skin grafting. Commercially available artificial dermis composed of collagen sponge was employed as a control. Grafted skin survival in all groups was evaluated according to macroscopic and histological appearances 2 weeks after transplantation. The take rate of auto-skin was higher in Groups I-IV than in control. The take rate of auto-skin was also higher for Groups II and IV than for Groups I and III. This finding indicates that CDS containing human fibroblasts is able to provide more suitable conditions for rat's auto-skin engraftment. The take rate of auto-skin in Group IV was >84%, showing the best results. This finding suggests that CDS comprising highly biodegradable matrix is acceptable for the engraftment of auto-skin, creating no physical barrier to interactions between the wound bed and auto-skin.