RESUMO
Objective To study the effect of osgentide (OST) on proliferation of mouse preosteoblast MC3T3-E1 under simulated microgravity ( SMG ) .Methods Under normal conditions , cell proliferation was evaluated by MTT assay to screen an OST compound of an effective concentration after MC 3T3-E1 cells were treated with series OSTs .Furthermore, cell proliferation and cell cycle distribution of MC 3T3-E1 cells were analyzed after treatment with 1 nmol/L OST5 by MTT assay and by flow cytometry ( FCM) scanning under SMG .Results Under normal conditions , 1 nmol/L OST5 was able to significantly promote the proliferation of MC3T3-E1 cells (P<0.01).Under SMG, proliferation of MC3T3-E1 cells was significantly inhibited and more cells entered G 1 than under normal conditions (CN).The proportion of S phase of MC3T3-E1 cells after treatment with 1 nmol/L OST5 ( OST-SMG) for 3 d was higher than that of untreated MC 3T3-E1 cells under SMG,suggesting that OST5 could promote DNA synthesis ( P<0.05 ) .Conclusion OST5 facilitates the proliferation of MC3T3-E1 cells under SMG, which provides a basis for the use of OST5 in the prevention and treatment of bone loss relat-ed to microgravity .