부산대학교 도서관

Mesenchymal stem cells (MSCs) are potential candidates for tissue engineering and regenerative medicine applications. Stromal tissues, from which MSCs are extracted, exist all over the body, suggesting that their precursors are locally available in multiple organs, providing a source of MSCs for homeostasis and repair of tissues. Teeth are one of the organs that contain MSCs. The understanding of properties of the different resident dental-derived stem cell populations may lead to the development of biologically based dental therapies. The continuously growing mouse incisor provides a highly accessible model to study stem cell behavior. Therefore, considering the importance of clinical applications of MSCs obtained from dental pulp, an experimental animal model was developed to study the behavior of different populations of MSCs. Incisors from 7-day postnatal mice were extracted from the mandible and maxilla and pulp tissue was dissociated using collagenase / dispase. The cell suspension was incubated to 80% confluence. The RNA was extracted from the cells, quantified, and transcribed into cDNA. For gene expression analysis (qPCR), MSCs clusters of differentiation genes (CD90, CD73, CD105) were used. For differentiation analysis, cells were incubated for 21 days in specific differentiation media (osteogenic, adipogenic, and chondrogenic) and analysed by immunocytochemistry. Flow cytometry (FACS) was also performed to sort CD90 positive cells. Thus, the newly dissociated cell suspension was incubated with anti-CD90 antibody. The FACS sorted cells were cultured until confluence and were again analysed by qPCR. MSCs obtained from the pulp of mouse incisors presented the minimum criteria for the definition of multipotent MSCs, that is, they expressed CD90, CD73, and CD105 and differentiated in vitro into three cell lineages. However, clusters of differentiation genes were more remarkable for CD90 positive cells than for non-FACS sorted cells. This is an indication that, among the MSC populations of the incisor pulp, there are different potentials for cell differentiation. The continuously growing mouse incisor has in its pulp tissue different niches and populations of stem cells that have different behavior regarding the potential for differentiation. [ABSTRACT FROM AUTHOR]