Platelet supernatant promotes proliferation of auricular chondrocytes and formation of chondrocyte mass

Recently proposed procedures for in vitro generation of new cartilage may b e difficult to perform in humans because so many chondrocytes are needed fo r tissue engineering. In this study the authors investigated new, efficient , law-cost techniques far the isolation and culture of chondrocytes from th e ear cartilage of the rabbit. They performed a law-density monolayer cultu re with a low concentration (0.5%, 1%) of human platelet supernatant and ob served cell proliferation (seeding efficiency, deoxyribonucleic acid synthe sis), matrix synthesis (glycosaminoglycan synthesis), and the expression of type I and type II collagen (reverse transcriptase polymerase chain reacti on). Seeding efficiency was increased in 1% of platelet supernatant-treated cultures by two to three times compared with untreated controls. One perce nt platelet supernatant had increased the incorporation of [H-3]-thymidine by 1.9 to 2.5 times at 72 hours compared with controls. Glycosaminoglycan s ynthesis was increased in platelet supernatant-treated chondrocytes at 96 h ours compared with controls. Chondrocytes treated with 1% platelet supernat ant showed a decreased expression of the type II collagen gene. Supplementa tion with a high concentration (10%) of the platelet supernatant provided t he conditions far in vitro chondrocyte mass formation. These results indica te that proliferation and matrix synthesis of auricular chondrocytes is sti mulated by a low concentration of platelet supernatant. On the other hand, chondrocytes were immobilized by a high concentration of platelet supernata nt. platelet supernatant may be useful as an inexpensive autologous source of multiple growth factors to enhance chondrocyte proliferation, and also m ay play the role of scaffold for chondrocytes, Additional investigation is underway to generate culture conditions that promote the differentiation as well as the proliferation of chondrocytes.