Abstract: Objective To observe the expression of stromal interaction molecule-1（STIM1）and other osteogenetic differentiation related factors （such as ALP，OCN，OPN） in bone marrow stromal stem cells（BMSCs）of postmenopausal osteoporosis patients.Methods BMSCs were cultured in the presence of osteogenic induction for 14d after obtained from postmenopausal osteoporosis patients.We analyzed the Ca²⁺ concentration and Ca²⁺ release activated Ca²⁺channel（CRAC）by Fluo-3 staining before and after osteogenic induction respectively.The expressions of STIM1 and other osteogenic differentiation related factors（ALP，OPN and OCN）were further measured and evaluated by quantitative real time PCR.Mineralization was evaluated by the calcium chelating dye alizarin red at the start of osteogenic induction and after 7 and 14 days.BMSCs were stained for alkaline phosphatase（ALP）at 14d.Results BMSCs were successfully cultured after osteogenic induction for 14d.The expressions of STIM1 and other osteogenic differentiation related factors（ALP，OPN，and OCN）in observation group were lower than the control group by RT-PCR（P<0.05）.Similarly，ALP staining was significantly reduced in observation group compared with the normal control cells（P<0.05）.Besides，the expression of STIM1 in observation group after osteogenic induction for 14d was reducing，but less than control group.Ca²⁺ concentration was reduced in observation group than control group（P<0.05）.The numbers of calcium chelating dye alizarin red in observation group were less than control group.Conclusion There are significant evidences that STIM1 in BMSCs would be contributed to the postmenopausal osteoporosis，which could provide a new research direction and therapeutic strategy for osteoporosis.

Key words: postmenopausal osteoporosis, bone marrow mesenchymal stem cells, stromal sympathetic molecules 1, alkaline phosphatase, calcium release activated calcium channel