Mesenchymal stem cells from murine amniotic fluid as a model for preclinical investigation.

BACKGROUND Despite the suitability of a mouse model for preclinical investigations; little is known regarding mesenchymal stem cells derived from murine amniotic fluid. This is the subject of the present study.  METHODS   Amniotic fluid was collected from NMRI mice during the second weeks of pregnancy and plated. The cells that adhered to the culture surfaces were propagated with three successive subcultures and then characterized. To determine the differentiation potential, the cells were cultivated under osteogenic, adipogenic, and chondrogenic conditions, and followed by specific staining and RT-PCR analysis for differentiation. The proliferative potential of the cells were measured with clonogenic assays, population doubling time and number and by growth curve plotting. Cellular aging was investigated with the senescence-associated ß-galactosidase staining method. RESULTS The amniotic fluid primary cell culture was composed of round flattened and fibroblastic cells. The latter dominated the culture after several passages. Successful tripotent differentiation of the isolated cells into bone, cartilage and adipose cells were indicative of their mesenchymal stem cells nature. The isolated cells appeared to be relatively proliferative cells as confirmed by the population doubling time value which was equal to about 69 hours. Furthermore, the cells were relatively clonogenic and they tended to initiate proliferation immediately after plating (there was no lag phase in their growth curve). ß-galactosidase positive cells were first observed at passage 3 and increased in number with subsequent passages. CONCLUSIONS Collectively it was concluded that murine amniotic fluid contained mesenchymal stem cells with relatively high proliferation property and typical tripotent differentiation potential.