The present study investigated the effects of hyperbaric oxygen (HBO) and platelet-derived growth factor-BB (PDGF-BB) in chondrocyte transplantation. In vitro, chondrocytes were treated with HBO, PDGF-BB, and HBO combined with PDGF-BB (H+P). Cell growth was analyzed using cell counting, MTT assay, and FACS analysis. mRNA expression of the PDGF-alpha receptor (PDGFR-alpha) and beta receptor (PDGFR-beta) was detected by RT-PCR. Protein expression of PDGFR-beta was detected by Western blotting. In vivo, chondrocytes and PDGF-BB were suspended in alginate as a transplantation system. Cartilage defects were grafted with this system and with or without HBO treatment. Released PDGF-BB concentration was quantified by ELISA. After 8 weeks, animals were sacrificed and the repaired tissues were examined. In vitro data suggested that each treatment increased cell growth via the up-regulated mRNA expression of PDGFR-alpha and increased cell accumulation in the S-phase. The H+P treatment was more additive in cell growth and in mRNA and protein expression of PDGFR-beta than HBO or PDGF-BB. In vivo results suggested that PDGF-BB delivery lasted for more than 5 weeks. Scoring results showed that each treatment significantly increased the cartilage repair. Safranin-O and type II collagen staining confirmed the hyaline-like cartilage regeneration in the repaired tissues. In situ up-regulation of PDGFR-beta expression partially explains the additive effect of H+P treatment in cartilage repair. Accordingly, H+P offers a potential treatment method for cartilage repair.
(c) 2009 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.