Characterisation of cells in regenerating cartilage from autotransplanted perichondrium. immunohistochemical expression of smooth-muscle actin, desmin, vimentin, and Ki-67.

Autotransplanted perichondrium from rib and ear sutured to the knee joints of 26 rabbits has been examined with immunohistochemistry and shows certain structural, functional, and proliferative characteristics of regenerating cartilage. Cryostat sections have been examined for the expression of smooth-muscle actin (SMA), desmin, vimentin, and Ki-67. In this rabbit model of perichondrial grafting SMA staining showed vivid vessel regeneration, particularly in the proliferating stage about two to three weeks after grafting, and no vessels in more mature parts one month or more after transplantation. Desmin staining showed expression and distribution similar to SMA. Vimentin staining shows the cytoskeleton of regenerating cartilaginous tissue and makes cellular borders apparent. Immunohistochemical expression of Ki-67 is constantly negative in perichondrial tissue from rib and ear before transplantation, clearly positive in the proliferative stage, but there is no expression in maturing cartilage. The study also shows that all human antibodies used are applicable in a rabbit model.