Collagen Based Multilayer Scaffolds for Meniscus Tissue Engineering: In Vivo Test Results
Meniscus is an important component of the knee joint since it performs several crucial functions such as shock absorption, load bearing and transmission, maintenance of joint stability, and lubrication. The results of common meniscal injury repair approaches are not fully satisfactory with low mechanical properties and long regeneration times. A 3D collagen-based construct consisting of multilayers of lyophilized sponges separated by electrospun fibrous mats was prepared previously to serve as a substitute for meniscus. Mechanical properties of the construct were studied in vitro and a 3 to 4 fold increase was observed when a double crosslinking method was used.
Rabbit meniscal cells were cultured in vitro, expanded and seeded onto the polymer scaffolds. 2 weeks later the substitute was implanted to the medial compartment of the rabbit knee joint. The implants were studied 3 and 10 weeks after transplantation. Histological and microscopical characterization showed a significant difference between the groups (Group I: control; Group II: cell free substitute and Group III: cell seeded substitute) with Week3 sample scores. Group III healing score was significantly lower than I and II, which was probably due to the the fibrous tissue surrounding the cell seeded material but this resulted in lower immunological responses. Moreover, the scores decreased from Week3 to Week10 indicating healing. Even though there were no statistically significant differences, the lowest values were observed with the tissue engineered substitute. Therefore, it can be concluded that in vivo studies showed the potential of the cell seeded artificial meniscus.