In vitro bonding of pre-seeded chondrocytes

This study investigated the capacity of seeded chondrocytes to join separate cartilage disc matrices in an in vitro model. Articular cartilage discs were harvested from pigs and devitalized by multiple freeze/thaw cycles. The devitalized cartilage discs were incubated in the presence (experimental group) or absence (control group) of chondrocytes for 10 days in order to allow chondrocytes to adhere to the matrix. After culturing, pairs of cartilage discs were held in apposition in a 48-multiwell plate and cultured for two and eight weeks. Twelve experimental composites (with cells) and twelve controls (without cells) were prepared per each time point. Samples were retrieved from culture and grossly inspected for adherence and processed for histological evaluation. Histological sections demonstrated the presence of new cartilage matrix formed by seeded chondrocytes bonding the two matrix discs together and producing glycosaminoglycans (GAG) able to diffuse within the devitalized tissue. Generally, gross adherence between the discs was demonstrated in the experimental samples, while the controls did not show any bonding. We conclude that isolated and seeded chondrocytes produce a new cartilaginous matrix, capable to join devitalized cartilage discs in vitro.