In vitro and in vivo evaluations of Loofah (<i>Luffa cylindrica</i>) micro- and PHBV nanofiber-integrated hydrogel scaffolds for meniscus regeneration

This study focuses on developing a composite hydrogel scaffold for meniscus regeneration by integrating loofah (Luffa cylindrica) microfibers and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) nanofibers as cell adhesion sites and mechanical reinforcements into a biomimetic collagen/chitosan matrix Scaffolds were chemically cross-linked with a natural cross-linker genipin (0.1%, 0.3%, 0.5%) and fabricated via freeze-drying to achieve optimal porosity and mechanical stability. The 0.3% genipin-cross-linked composite hydrogel scaffold (PL/ChtCol-3) demonstrated the highest compressive strength, damping capacity, and water absorption, and was selected for biocompatibility evaluation. In vitro studies using rabbit bone marrow-derived mesenchymal stem cells (rMSCs) confirmed the scaffold's nontoxicity and biocompatibility, promoting cell attachment, proliferation, and type II collagen expression. In vivo analysis was conducted using a standardized meniscus defect model in 24 New Zealand rabbits, divided into three groups: empty defect, cell-free scaffold, and cell-laden scaffold. Postimplantation assessments, including Micro-CT, biomechanical, histological, and immunohistochemical analyses showed that the cell-laden PL/ChtCol-3 scaffold significantly enhanced meniscus regeneration. Notably, it reduced defect volume and restored compressive modulus to levels comparable with native tissue. These findings demonstrate that the PL/ChtCol-3 scaffold, particularly when combined with rMSCs, holds strong potential as a biomimetic and regenerative platform for meniscus tissue engineering.