Growth Rule and Ultrastructural Characteristic of Rat Bone Marrow-derived Mesenchymal Stem Cells

Objective To investigate the biological characteristics of bone marrow mesenchymal stem cell (MSCs)from rat.Methods The rat MSCs from bone marrow were cultured by adhering to the culture plastic and identi- fied using immunohistochemical methods.Their growth axiom,light and electron microscopic features were observed.Re- sults MSCs proliferate fast before the seventh generation.The ceils present stagnation 1～2 days after inoculation and after 3 days the cells present logarithmic growth period.At the sixth day MSCs are into platform period.The cultured MSCs expressed CD44 and lacked CD45 in immunohistochemical analysis.Under the light mieroscope MSCs present fusi- form,spindle and polygon shape.The nuclei seat in the middle of the cells and have one or two nucleoli ;Under the elec- tron microscope MSCs have plentiful cytoplasm with mitochondria rough endoplasmic reticula and Golgi complexes.Their nuclei are round or oval and have obvious nucleoli.Conclusion The cultured MSCs have unique ultrastructrual charac- teristic.The growth traits of MSCs are stable in vitro and they can be used as the seed-cells in the study of tissue engi- neering.