Meniscus is mainly composed of three different cell types; chondrocytes(Ch) situate in the superficial zone, whereas fibroblast-like cells locate in the peripheral region having long cell extensions in contact with different parts of the matrix, fibrochondrocytes(FC), is from the inner part of the meniscus and show a clear cell associated matrix. The aim of this study is to develop meniscus cell population using with mesenchymal stem cells (MSCs). For this purpose, MSCs were isolated from rabbit bone marrow and verified by flow cytometry analyses using cell surface markers (CD73APC, CD90FITC, CD34PE, CD45PE/Cy5.5). The results indicate that CD73 and CD90-positive cells were 92.8%, and CD 45 and CD 34-negative cells were 52.4%. Differentiation potential of MSCs were also evaluated by differentiating into Ch, osteoblasts (Ob), adipocytes (Ad), fibroblasts (Fb). Histology stainings showed that differentiated Ch can produce proteoglycans, Ob have mineralization property, Fb have spindle shape and Ad have oil drops morphology. Afterwards Fb, Ch and undifferentiated MSCs (for formation of the FC) were seeded in same plate in cocktail medium and Fb, Ch, seeded individually, were used as control group. Proliferation activity of the cells was analyzed by XTT assay at 3^th,7^thand14^thdays. In addition, cells were analyzed by flow cytometry with identical surface markers at 3^th,7^thand14^thdays. Results show that cell cocktail have the greatest proliferation ability with a greater speed than the individual Ch or Fb cultures. In addition, FC formation was identified by histological staining. In conclusion, meniscus specific cell population has been successfully generated from the cell cocktail containing rabbit MSCs.

For the treatment of irreparable meniscal injuries, we developed a novel multilayer meniscal scaffold, consisting of collagen, strontium and cellulose derived from Luffa Cylindirica; and we evaluated its effects on meniscal regeneration and arthritic changes in a rabbit partial meniscectomy model.

The meniscus has a key role in shock absorbtion, load distribution, chondroprotection and stability of the knee joint. Meniscal injuries are one of the most common orthopedic injuries and may lead to degenerative cartilage changes and eventually osteoarthritis. Repair of the meniscal tissue is the treatment of choice for patients with a meniscus lesion, however, this is not always possible, especially for degenerative tears or injuries located on the inner avascular zone. To overcome the devastating outcomes of meniscectomy for such injuries, several materials have been developed and tried to replace the resected meniscal tissue. These scaffolds were designed primarily to relieve pain after meniscectomy, and later on were aimed to prevent osteoarthritis and cartilage damage that may develop in the future. In the quest for optimum scaffold material small intestine, tendons and other isolated tissues, collagen and polyurethane have been researched. Nevertheless, none of these materials have absolutely proven satisfying identical replacement of resected meniscal tissue. Therefore, we developed and investigated a novel multilayer meniscal scaffold, consisting of collagen, strontium and cellulose derived from Luffa Cylindirica (a cucumber shaped and sized plant, known as sponge gourd). The aim of the study was to evaluate the meniscal regeneration and arthritic changes after partial meniscectomy and application of novel multilayer meniscal scaffold in a rabbit model and to compare the results with clinically used polyurethane scaffold (Actifit, Orteq Ltd, London, UK)

Sixteen male, mature, NewZealand rabbits weighing between 2600–3500 g were randomly divided into three groups. All groups underwent knee surgery via a medial parapatellar approach and a reproducible 1.5-mm cylindrical defect was created in the avascular zone of the anterior horn of the medial meniscus bilaterally. Defects were filled with the polyurethane scaffold in Group 1 and novel multilayer scaffold was applied to fill the defects in Group 2(n:6). Four rabbits in Group 3 did not receive any treatment and defects were left empty. Animals were sacrified after 8 weeks and bilateral knee joints were taken for macroscopic, biomechanical, and histological analysis.

No signs of inflammation or infection were observed in all animals. Macroscopic evaluation of tibial plateaus after excision of menisci was performed with digital images of inked condylar surfaces. No significant degenerative changes were detected between groups. Digital photographs of excised menisci were also obtained and surface areas were measured by a computer software (Image J version 1.46, National Institute of Health, Bethesda, MD). There was a slightly larger meniscus area in the first two groups than the no treatment group, however, this was not found significant. Indentation testing of the tibial condyle and compression tests for the relevant meniscal areas with a diameter of 3mm was also performed in all groups. Histological analysis was made and all specimens were stained with safranin O and scored according to a scoring system.

In this study, the initial evaluation of novel multilayer meniscal scaffold demonstrated promising biomechanical and histological results; besides no adverse events related to scaffold material was observed.