The purpose of this study was to examine the characteristics of donor and host cells immunohistochemically in early remodeling process after transplantation of Achilles tendon with and without live cells for a rotator cuff defect. Sprague Dawley (SD) rats and Green fluorescent protein transgenic rats (GFP rats) were used in this study. Tendinous defects were made close to the supraspinatus tendon insertion. 3 models were made. Group A-1: Achilles tendons of GFP rats were transplanted into the defects of SD rats. Group A-2: SD rats Achilles were transplanted into GFP rats. Group B: SD rats frozen Achilles were transplanted into GFP rats. At 3 and 7 days after surgery, sections stained with antimacrophage antibody and antiHSP47 antibody (collagen production cell specific antibody) were assessed immunohistochemically, and localization of positive cells was also evaluated. The graft was surrounded by signal positive cells of macrophage at each day. There were no macrophage positive cells derived from the donor. Signal positive cells of HSP47 was infiltrated into the graft gradually. There were some co-expressions between HSP47 positive cells and donor cells. It was possible easily to distinguish a host or donor cell by using GFP rats. Both macrophage and HSP47 positive cells were important to play their parts of remodeling. This is the possibility for the live HSP47 positive donor cells to participate indirectly in the tendon remodeling.
