Mesenchymal stem cells (MSCs) have been successfully isolated from a broad range of adult, fetal, and other nonembryonic tissues. Fetal lung has been identified as a rich source of MSCs. However, the biological characteristics and differentiation potential of fetal lung MSCs remain to be explored. In this study, we established a series of methods for isolation and expansion of fetal lung MSCs. These MSCs could withstand more than 40 passages without obvious decline in proliferation ability, significant changes in morphology, and expression of cell markers. Flow cytometric analysis showed that fetal lung MSCs expressed CD13, CD29, CD44, CD90, CD105, CD166, and HLA-ABC, but not CD14, CD31, CD34, CD38, CD41a, CD42b, CD45, CD49d, CD61, CD106, CD133, and HLA-DR. Cell cycle analysis revealed that when the MSCs reached their log phase of growth, more than 90% of the cells were in G 0 /G 1 phase while the proportion of cells in S phase and G 2 /M phase were about 5.56% and 2.08% cells, respectively. These MSCs could differentiate into neural cells in addition to their mesenchymal differentiation potential. Our data suggest that the fetal lung MSC population is an alternative source of stem cells for cell-based therapy of neurological defects or mesenchymal-originating diseases.Key words: Mesenchymal stem cell; Bone marrow; Fetal lung; Stem cell plasticity; Neural differentiation INTRODUCTIONduced and terminally differentiated into osteoblasts, chondrocytes, adipocytes, hypocytes, tenocytes, myotubes, neural cells, and hematopoietic-supporting stroma (3,13, Self-renewal capacity, long-term viability, and multilineage potential are the basic properties of stem cells 16,18,19,21,22,31). The multipotential capability of these cells, their straightforward isolation and culture as well (8). Within stem cell research, multilineage potential embryonic stem cells and mesenchymal stem cells (MSCs) as high ex vivo expansive potential make the MSCs an attractive therapeutic tool for various kinds of diseases. from adults and fetuses are the two fields that have been extensively investigated. Embryonic stem cells, whichTo date, MSCs have been isolated from a broad range of tissues and organs, including bone marrow, umbilical are derived from mammalian embryos in the blastocyst stage, can proliferate indefinitely and differentiate into cord blood, the wall of artery, umbilical cord vein, peripheral blood, fetal bone marrow, liver, spleen, etc. (7, derivatives of all three germ layers (10), but the adult stem cells may have less replication and differentiation 11,12,20,21,25,32). Current investigation on the immunophenotype and differentiation potential of second tricapacities. Until recently, it was thought that tissuespecific adult stem cells could only differentiate into mester bone marrow, liver, lung, and spleen revealed that cultured-expanded cells from these tissues are phecells of their origin. However, current studies have suggested that tissue-specific stem cells may have greater notypically similar but exhibit heterogenei...

No abstract