Platelet-rich plasma loaded hydrogel scaffold enhances chondrogenic differentiation and maturation with up-regulation of CB1 and CB2

Three-dimensional scaffolds like hydrogels can be used for cell and drug delivery and have become a major research focus in tissue engineering. Presently, we investigated the regenerative potency of platelet-rich plasma (PRP) combined with a chondrocyte/hydrogel composite scaffold in the repair of articular cartilage defects using a rabbit model. Primary isolated joint chondrocytes from the trachlear groove of rabbit were cultured in hydrogels as follows; hydrogel (2900 Pa or 5900 Pa) + chondrocytes and hydrogel + chondrocytes + PRP for in vitro analysis and in vivo implantation. The 5900 Pa hydrogel markedly increased cellular viability and development in a time-dependent manner. Furthermore, the hydrogels attenuated the expression of SOX-9, aggrecan, and type II collagen. PRP-containing hydrogels produced an immediate increase in mRNA levels of cannabinoid receptor (CB) 1 and CB2, compared with control and PRP-free hydrogels. Osteochondral defects were enhanced recovery with formation of cartilage and perichondrium in the 5900 Pa hydrogel + chondrocytes + PRP. Hydrogel may provide a suitable environment for proliferation and maturation of joint chondrocytes in relation to the gelation density and bioactive sources like PRP resulting in improvement for cartilage regeneration. (C) 2012 Elsevier B.V. All rights reserved.