Characteristics of a scaffold-free articular chondrocyte plate grown in rotational culture.

We investigated whether articular chondrocytes could form three-dimensional tissue-engineered cartilage in a rotational culture system without a scaffold. A suspension of chondrocytes derived from Japanese white rabbits was inoculated into a mold. Eight hours later, the cell suspension in the mold showed cell aggregation, forming a chondrocyte plate. The mold was removed, and the plate was cultured under static conditions. After 7 days of primary static culture, the plate was cultured under dynamic conditions, using rotational culture. After 2-3 weeks of rotational culture, the chondrocyte plate maintained a constant form and was considered stable enough to be handled with surgical pincers. Conversely, after 3 weeks of static culture, the plate gradually changed into an arch over that time. Histological and immunohistochemical evaluations indicated that the plate had cartilaginous qualities in terms of cell distribution and organization and the production of glycosaminoglycans and type II collagen in rotational cultures. Chondron units were detected with scanning electron microscopy. In contrast, a plate cultivated in static culture for 3 weeks was irregular in shape, and histological analysis indicated irregularly accumulated glycosaminoglycans. TUNEL-positive cells had increased significantly in the central region in 3-week static cultures, compared with those in 3-week rotational cultures. In this study, cartilaginous tissue in a scaffold-free environment has been produced. Significantly rotational cultures produce a construct, which is stable enough to be handled with surgical forceps after only 2 weeks of rotational culture. This system should be useful for implantation in the future.