Effectiveness of three extraction techniques in the development of a decellularized bone–anterior cruciate ligament–bone graft

In this study, porcine bone–anterior cruciate ligament–bone (B–ACL–B) grafts were decellularized using one of three protocols incorporating surfactants lauryl sulfate (SDS), Triton X-100, and/or an organic solvent (tributyl phosphate (TnBP)). The effectiveness of Triton–SDS, Triton–Triton or Triton–TnBP treatments in removing cellular materials was determined and possible changes in biochemical composition and mechanical properties due to each treatment were investigated. Treatment with Triton–SDS was most effective at removing cell nuclei and intracellular protein (vimentin) from the ACL but affected both the collagen and glycosaminoglycan (GAG) components of the extracellular matrix while increasing the tensile stiffness of the ligament. Triton–Triton was the least effective of the three treatments in terms of cellular extraction, but did not significantly change the mechanical and biochemical properties of the ACL. Triton–TnBP matched the level of decellularization achieved by Triton–SDS in terms of visible cell nuclei; however, the extraction of intracellular vimentin was less consistent. TnBP treatment also slightly decreased the collagen content of the ACL but did not alter its mechanical properties. Overall, all three decellularization treatments maintained adequate mechanical and biochemical properties of B–ACL–B grafts to justify the further investigation of all three decellularization protocols. The selection of a superior treatment will depend on future studies of the propensity of treated tissues for repopulation by host ACL fibroblasts and, ultimately, on any immunogenic and/or remodeling host response induced in vivo.