Growth factor treated tensioned synoviocyte neotissues: towards meniscal bioscaffold tissue engineering

Meniscal injury is a common cause of osteoarthritis, pain, and disability in dogs and humans, but tissue-engineered bioscaffolds could be a treatment option for meniscal deficiency. The objective of this study was to compare meniscus-like matrix histology, composition, and biomechanical properties of autologous tensioned synoviocyte neotissues (TSN) treated with fetal bovine serum (TSNfbs) or three chondrogenic growth factors (TSNgf). Fourth passage canine synoviocytes from 10 dogs were grown in hyperconfluent monolayer culture, formed into TSN, and then cultured for 3 weeks with 17.7% FBS or three human recombinant TSNgf (bFGF, TGF-β1, and IGF-1). Cell viability was determined with laser microscopy. Histological architecture and the composition of fibrocartilage matrix were evaluated in TSN by staining tissues for glycosaminoglycan (GAG), α-smooth muscle actin, and collagen 1 and 2; quantifying the content of GAG, DNA, and hydroxyproline; and measuring the gene expression of collagens type 1α and 2α, the GAG aggrecan, and transcription factor Sry-type Homeobox Protein-9 (SOX9). Biomechanical properties were determined by materials testing force-deformation curves. The TSN contained components and histological features of mensical fibrocartilage extracellular matrix. Growth factor-treated TSN had higher DNA content but lower cell viability than TSNfbs. TSNgf had greater fibrocartilage-like matrix content (collagen 2 and GAG content with increased collagen 2α and SOX9 gene expression). Additionally, TSNgf collagen was more organized histologically and so had greater tensile biomechanical properties. The results indicate the potential of TSN when cultured with growth factors as implantable bioscaffolds for the treatment of canine meniscal deficiency.