Implants of hypertrophic scars and keloids into the nude (athymic) mouse: viability and morphology.

Pieces of hypertrophic scars and keloids were implanted into subcutaneous pockets of nude (athymic) mice and carried for varying times up to 246 days. No rejection phenomena were observed. Microvascular anastomosis occurred between host and implant within the first several days. Remodeling of the edges of the implant occurred very early. Multiple regression analysis of volume measurements suggests there was a size reduction of the implants with time. Yet virtually all implants retained their original histotypic character regardless of the length of implantation. The nodular character typical of all hypertrophic scars and keloids was retained in every case. Histologic analysis, confirmed by transmission electron microscopy, demonstrated a sustained cellular character. The degree and magnitude of microvascular occlusion was also sustained. Use of the nude mouse for implants of hypertrophic scar or keloid sustains true viability and morphology of the lesions. This procedure shows clear potential as an experimental model for the study of these lesions.