Introduction: Meniscus is an important component of the knee joint since it has a crucial function like shock absorption, load bearing and transmission, maintenance of joint stability and lubrication. A common approach used these days to repair meniscal injuries is the use of various tissue substitutes; however, the results are not fully satisfactory in terms of mechanical properties and the long regeneration time. The aim of this study was to design a multilayered, tissue engineered, 3D meniscus substitute.
Materials and Methods: Insoluble collagen type I purified from bovine Achilles’ tendon was used to prepare the foams through lyophilization. Rat tail collagen I was used in combination with a synthetic polymer (PLGA, 50:50) to prepare the nano/microfibers by electrospinning. A multilayered construct was prepared by combining three foams of different mechanical strength with nanofibrous mats in between. The foams were crosslinked both physically (dehydrothermally (DHT)) and chemically (EDC/NHS). On the other hand, Coll-PLGA (1:1, v/v) nanofibers were prepared by electrospinning. The final 3D construct was then seeded with rabbit meniscal cells and incubated for a period of 10 days in cell culture. The construct was then implanted into White New Zealand rabbits. Three different groups (control, unseeded and cell-seeded) were tested in vivo to check the compatibility of the produced meniscus after 3 and 10 weeks of implantation.
Results and Discussion: In this study, a 3D construct was prepared as a substitute for meniscus. Mechanical properties of the construct were tested in vitro in order to have the highest possible properties. A combination of both physical and chemical crosslinking methods showed a 3-to-4 fold increase in all mechanical properties of the construct compared to the one crosslinked with only DHT or EDC/NHS. The final 3D construct consisting resulted in a 2-fold higher compressive properties (444.6 ± 69 kPa) than the foams tested separately (234.9 ± 16.2).
The construct was implanted into medial compartment of the rabbit knee joint. Preliminary in vivo studies (histological and microscopical characterization) have shown no inflammatory response in all cases and the most promising results were obtained with the cell-seeded scaffolds.
References:
[1] A Ndreu Halili, N, Hasirci, V. Hasirci. A multilayer tissue engineered meniscus substitute. J Mater Sci: Mater Med., 25 (4) 1195-1209.