In Vivo Study of ACL Regeneration Using Silk Scaffolds In a Pig Model

Abstract

Although most in vitro studies indicate that silk is a suitable biomaterial for ligament tissue engineering, in vivo studies of implanted silk scaffolds for ligament reconstruction are still lacking, especially in a big animal. The objective of this study is to investigate anterior cruciate ligament (ACL) regeneration using mesenchymal stem cells (MSCs) and silk scaffold in a pig model. The scaffold was fabricated by incorporating microporous silk sponges into knitted silk mesh, which mimicked the structures of ligament extracellular matrix (ECM). In vitro culture already demonstrated that MSCs on scaffolds proliferated vigorously and produced abundant collagen. The MSCs/scaffold was implanted to regenerate ACL in a pig model. After 24 weeks, histology observation showed that MSCs were distributed throughout the regenerated ligament and exhibited fibroblast morphology. The key ligament ECM components including collagen I, collagen III, and tenascin-C were produced prominently. The tensile strength of regenerated ligament also met the mechanical requirements. In conclusion, the results imply that silk scaffold has great potentials in future clinical applications.