Tissue-engineered intrasynovial tendons: Optimization of acellularization and seeding

The purpose of this research was to develop a tissue-engineered intrasynovial flexor tendon construct with the use an acellularized flexor tendon scaffold repopulated with intrasynovial tendon cells. New Zealand white rabbit intrasynovial flexor tendons were acellularized by the following methods: high concentration NaCl + SDS, Trypsin/EDTA, Trypsin/EDTA Triton X-100, Triton X-100, Triton X-100 + SDS, and freezing -70 °C followed by Trypsin/EDTA + Triton X-100. Epitenon and endotenon cells were also isolated from rabbit intrasynovial tendons and expanded in culture. Acellularized tendon scaffolds were then reseeded with these cells. A subset of epitenon and endotenon cells was labeled with green and red fluorescent markers, respectively, to further characterize the preferred location of their attachment. Optimal acellularization was achieved by freezing at -70 °C followed by Trypsin/EDTA + Triton X-100. After reseeding, light microscopy of tendon constructs showed attachment of both epitenon and endotenon to the tendon scaffolds, with endotenon cells more likely to be found the core of the scaffold. An intrasynovial tendon construct was developed with the use of acellularized intrasynovial tendons repopulated with intrasynovial tenocytes. These constructs grossly resemble normal intrasynovial tendons, and cells were found both on the surface and the core of the construct histologically. This new construct represents an important first step in developing a viable tissue-engineered flexor tendon.