Histochemical analyses of tissue-engineered human menisci.

The field of tissue engineering remains one of the least explored areas of current meniscal research but holds great promise. In this investigation, meniscal fibrochondrocytes were isolated from fresh human meniscal tissue and seeded onto synthetic polyglycolic acid (PGA) scaffolds. Constructs were implanted into the dorsal subcutaneous space of athymic nude mice. Control scaffolds, devoid of meniscal cells, were simultaneously implanted in additional mice. Constructs were harvested over 12 weeks and treated with a variety of histochemical stains to analyze general specimen morphology, cellular viability and proliferation, and collagen secretion. Results indicate that meniscal fibrochondrocyte proliferation increased over the time of implantation with cellular consolidation occurring as the PGA scaffolding was progressively hydrolyzed. Collagen production also increased over time. There were favorable similarities between constructs and human meniscal controls in terms of cellular morphology, phenotypic expression, and collagen production. These initial findings demonstrate procedures supporting proliferation of meniscal fibrochondrocytes, expression of fibrochondral phenotype, and the formation of putative meniscal tissue.