Histological, Physical Studies after Xenograft of Porcine Ear Cartilage

BACKGROUND Because of the relatively similar size of organs to human and the physiological and structural similarities, the use of porcine as xenograft donors is progressing very actively. In this study, we analyzed the characteristics of porcine ear cartilage and evaluated its suitability as graft material in reconstructive and cosmetic surgery. METHODS The auricular cartilage was harvested from two pigs, and subjected to histological examination by immunohistochemical staining. To determine the collagen content, samples were treated with collagenase and weight changes were measured. After sterilization by irradiation, the samples were grafted into rats and stained with Hematoxylin and Eosin and Masson Trichrome to observe inflammation and xenograft rejection. RESULTS In IHC staining, extracellular matrices were mainly stained with type II collagen (20.69%), keratin sulfate (10.20%), chondroitin sulfate (2.62%), and hyaluronic acid (0.84%). After collagenase treatment, the weight decreased by 68.3%, indicating that about 70% of the porcine ear cartilage was composed of collagen. Upon xenograft of the sterilized cartilages in rats, inflammatory cells were observed for up to 2 months. However, they gradually decreased, and inflammation and reject-response were rarely observed at 5 months. CONCLUSION The porcine ear cartilage was covered with perichondrium and cellular constituents were found to be composed of chondrocytes and chondroblasts. In addition, the extracellular matrices were mainly composed of collagen. Upon xenograft of irradiated cartilage into rats, there was no specific inflammatory reaction around the transplanted cartilage. These findings suggest that porcine ear cartilage could be a useful alternative implant material for human cosmetic surgery.