OBJECTIVETo study the role of the soluble factors secreted by tissue engineered cartilage in promoting bone marrow stromal cells (BMSCs) chondrogenesis as an important aspect.

METHODSPorcine BMSCs, chondrocytes and dermal fibroblasts were respectively in vitro expanded and then seeded onto the polyglycolic acid/polylactic acid (PGA/PLA) scaffold. After 3 days, they were indirectly co-cultured by transwell. BMSCs-scaffold constructs were co-cultured with chondrocytes-scaffold constructs as experiment group (Exp), while co-cultured with fibroblasts-scaffold constructs as control group. BMSCs with the same cell number were seeded onto the scaffolds as another control group. There were 3 specimens in each group. All specimens were harvested after in vitro indirect co-culture for 8 weeks. Gross observation, histology, immunohistochemistry and RT-PCR were used to evaluate the results.

RESULTSThe BMSCs-scaffold constructs co-cultured with chondrocytes-scaffold shrunk gradually during in vitro culture, but formed the mature lacuna structures and metachromatic matrices, collagen II expression could be observed by immunohistochemistry and RT-PCR examination. In the control group, the constructs shrunk greatly during in vitro culture and showed mainly fibrous tissue.

CONCLUSIONSThe soluble factors secreted by chondrocytes can solely induce chondrogenic differentiation of BMSCs and thus promote the in vitro chondrogenesis of BMSCs.