Donor cell fate in tissue engineering for articular cartilage repair

Articular cartilage repair is a clinical challenge because of its limited i ntrinsic heating potential. Considerable research has focused on tissue eng ineering and transplantation of viable chondrogenic cells to enhance cartil age regeneration. However, the question remains: do transplanted allogenic cells survive in the repair with time? This study assessed donor cell fate after transplantation of male New Zealand White rabbit perichondrium cell a nd polylactic acid constructs into osteochondral defects created in the med ial femoral condyles of female New Zealand White rabbits. Repair tissue was harvested at 0, 1, 2,3,7, and 28 days after implantation and was evaluated for cell viability and total cell number using confocal microscopic analys is. The number of donor cells in each sample was estimated using quantitati ve polymerase chain reaction targeting a gender-specific gene present on th e Y-chromosome, the sex-determining region Y gene, and a control deoxyribon ucleic acid present in male and female cell deoxyribonucleic acid, the matr ix metalloproteinase-1 gene promoter. Average cell viability was found to b e 87% or more at all times. Donor cells were present in repair tissue for 2 8 days after implantation. However, the number of donor cells declined from approximately 1 million at Time 0 to approximately 140,000 at 28 days. Thi s decline in donor cells was accompanied by a significant influx of host ce lls into the repair tissue. This study shows that the sex-determining regio n Y gene is a valuable marker for tracking the fate of transplanted allogen ic cells in tissue engineering.