KINETIC CHANGES OF HUMAN BONE MARROW HEMOPOIETIC STEM CELLS CULTURED IN VITRO
CHU JEN-PAO,CHU JUN-JIE,YAN CHUAN-SHUANG,SHI JUN (Institute of Radiation Medicine,Academy of Millitary Medical Sciencers,Beijing)
The culture system of human bone marrow cells was established by two successive inoculations of 10~7 BM cells.The first one was to induce the formation of adherent cell layer on the inner wall of the flask and the second is implanted on the surface of adherent cell layer facilitating the lodging and functioning of hemopoietic stem cells.In this way the BM hemopoietic stem cells can be kept in active state for a long period.The number of CFU-C and CFU-E was estimated weekly which may reflect the activity of CFU-S.The results showed that under the conditions of culture in vitro,a con-siderable number of CFU-C could be maintained as long as 9 weeks and that of CFU-E less than 5 weeks.The cel-lular elements suspended in the cul-ture medium were predominantly gra-nulocytes at different stages of ma-turation which lasted for a period of culture in parallel with that of CFU-C.The red cells disappeared after 3 weeks of culture and the lymphocytes persisted not longer than 5 weeks. On the whole,during the first 7 weeks of culture,the suspended cells in every culture flask were increasing in number.From the suicide experi-ment,it was proved that within the 6 weeks of culture at least a part of CFU-C was continuously entering the stage of DNA synthesis.It is apparent that under the in vitro culture condi-tions the differentiation of CFU-S to-wards the granuloid line continues throu-ghout the whole period of culture,but the differentiation of erythroid and lym-phoid line is maintained only a few weeks. After 7 weeks of culture,the total number of suspended cells began to decline.The hemopoietic stem cells as represented by CFU-C disappeared af-ter 9 weeks and so the suspended cells but rather slowly.Another interesting factor was the presence of CSF in the culture medium of human BM cells.This indicates that there might exist some humoral regulation substances produced in the in vitro culture system.