In Vitro and In Vivo Evaluations of Loofah Micro- and PHBV Nano-Fiber Integrated Hydrogel Scaffolds for Meniscus Regeneration

Meniscus is a tissue that has vital properties for knee stabilization, shock absorption, axial load distribution, joint lubrication, and nutrition of articular cartilage. This study aims to produce loofah micro- and poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) nano-fiber integrated collagen and chitosan polymer-based composite hydrogel scaffolds crosslinked with three different concentrations of genipin (0.1, 0.3, and 0.5%) for meniscus regeneration. The scaffold crosslinked with 0.3% genipin, which exhibites the highest compression strength with high water absorption and damping capacities, is chosen as the optimal scaffold for further in vitro and in vivo analyses. In vitro biocompatibility studies are conducted by using rabbit bone marrow-derived mesenchymal stem cells. Accordingly, the composite hydrogel scaffold is found to be non-toxic, and capable of promoting cell adhesion and proliferation as well as collagen immunopositive, especially for type II collagen. In vivo analysis is performed by using 24 adult male New Zealand rabbits in three groups (empty defect, cell-free and cell-laden implanted scaffolds) with a standardized meniscus regeneration model. In conclusion, the cell-laden scaffold implanted group shows better meniscal healing based on the post-implantation biomechanical, histological, immunohistochemical, and Micro-CT evaluations.