Investigation of interactions between mesenchymal stem cells-polycaprolactone (ɛ-caprolactone) scaffolds and improvement of 3d tissue model for the use of cartilage tissue engineering

Human cartilage damage is one of the most important health problems that increasing with each passing day in the world and Turkey. According to a study conducted by Turkish ministry of health in 2010, there are 4.7 million people who are above 15 have the cartilage degeneration illness. Although, wide variety of treatments (conservative and surgery) are being applied, crucial problems in the field are still waiting to be solved. For this, the importance of cartilage tissue based studies have been grown in recent years. Especially, stem cell and biomaterial based technology development in tissue engineering field has caused to open new horizons and hopes to solve these problems. Poly-epsilon captolactone (PCL) is one of the scaffolds that is being used widely among the biomaterials in tissue engineering. Although there are some researches has been studied with poly-epsilon caprolactone (PCL) and mesenchymal stem cells (MSC), these studies are not enough to explain which stem cell source better interacting with PCL scaffold. Besides, there are only a few research studied the effect of three dimensional culture (which is formed from PCl and mesenchymal stem cells) on the chondrocyte differentiation. Furthermore, we couldn't find any research about the PCL scaffold and olfactory bulb sourced mesenchymal stem cell interactions to use in cartilage tissue engineering. According to the information above, the goal of this thesis study is investigation of the interaction between PCL scaffold and different sourced mesenchymal stem cells (such as adipose, umbilical cord matrix, and olfactory bulb), identification of which mesenchymal stem cell source better for differentiation to cartilage tissue on the three dimensional tissue cultures and suggestion of optimum stem cell source to use in cartilage tissue engineering according to these studies. To reach the goal in the scope of this thesis; three dimensional culture models of adipose, umbilical matrix and olfactory bulb tissue sourced mesenchymal stem cells on PCL scaffold have been optimized along 12 days with the MTT (3-(4,5-dimethyltriazol-2-il)-2,5- diphenyltetrazolium bromide), aliveness analyzes with alive/death dying, CM-DiI dying and SEM (Scanning Electron Microscope) analyzes. The chondrogenic differentiation in three dimensional culture models has been investigated along 26 days with; MTT, alive/death dying, NO (Nitric Oxide) analyzes, SEM images, real-time PCR analyzes following RNA isolation and cDNA obtainment and histological analyzes. As results of all these studies, chondrogenic differentiation of umbilical matrix-PCL scaffold based three dimensional culture model is faster than the adipose tissue and olfactory bulb sourced mesenchymal stem cell-PCL based cell culture models. According to real time-PCR results, olfactory bulb sourced mesenchymal stem cell-PCL scaffold based three dimensional culture model showed the most closest expression pattern of the hyaline cartilage tissue gene expression pattern. ANOVA and Student T tests are applied to MTT and NO analyse results to determine their statistical significance. All data satistics conducted with Statistical Packages of Social Sciences (SPSS, version 19.0 for Windows) program and p<0,05 value assumed as significance threshold. As a result, in the scope of this thesis for the first time; the interaction between PCL scaffolds and different sourced mesenchymal stem cells (such as adipose umbilical matrix and olfactory bulb tissue) has been investigated comparatively. According to obtained results; it is determined that the PCL can interact with all three different sourced mesenchymal stem cells but the most optimal result has been obtained from the olfactory bulb sourced mesenchymal stem cell-PCL interaction model. Furthermore, for the first time in cartilage tissue engineering, it is searched out that olfactory bulb sourced mesenchymal stem cells can differentiate into chondrocytes on the three dimensional culture model prepared with the PCL scaffolds. These results indicate that usage potential of a new mesenchymal stem cell source in cartilage tissue engineering has been risen. Keywords: Scaffold, cartilage tissue engineering, mesenchymal stem cells