[Effects of high magneto-gravitational environment on calcium/calmodulin signal of MG63 osteoblast-like cells].

AIM: To investigate the effects of high magneto-gravitational environment on Ca(2+);]/calmodulin (CaM) signal of MG63 osteoblast-like cells. METHODS: A special designed large gradient high magnetic field could produce three different high magneto-gravitational environments including µg (12 T), 1 g (16 T) and 2 g (12 T). The effects of high magneto-gravitational environments on intracellular free Ca(2+);] concentration ([Ca(2+);](i);) and protein expression including calmodulin (CaM), myosin light chain kinases (MLCK) and phosphorylated Ca(2+);]/CaM dependent protein kinase II(pCaMKII) were measured by Fluo-3/AM or Western blot, respectively. RESULTS: When compared with control group, an increase of [Ca(2+);](i); of MG63 was caused by strong magnetic field; Compared to 2 g, µg decreased [Ca(2+);](i); of MG63. The protein expression of CaM and pCaMKIIof MG63 cells was decreased by simulated weightlessness. CONCLUSION: [Ca(2+);](i); of MG63 cells was increased by strong magnetic field; simulated weightlessness inhibited Ca(2+);/CaM signaling of MG63 cells.

[Roles of autocrine soluble fibronectin on the maintenance of cell shape of osteosarcoma MG-63 cells].

AIM: To investigate the roles of autocrine soluble FN of MG-63 cells in cell shape maintaining. METHODS: Human osteosarcoma MG-63 cells (1 × 10(4); cells/cm(2);) were routinely cultured in MEM medium+10% fetal bovine serum (FBS) for 24 h and then the medium was replaced by fresh medium(the group without autocrine soluble FN), conditional medium of collected after 24 h of MG-63 cells (the group containing autocrine soluble FN ) and fresh medium with 20 microg/mL FN( the group with plasma FN) after 24 h, and the cell morphology was observed using phase contrast microscope; The concentrations of soluble FN in fresh and conditional medium were detected; Microfilament and insoluble FN changes of MG-63 cells were investigated. RESULTS: The concentration of soluble FN in conditional medium is much higher than that in the fresh medium (P<0.01). Fresh medium will result in the cell shape changing from spindle to round for 0.5 h. The cell began to spread for 1 h, and the cell shape recovered for 2 h; Conditioned medium has no significant effects on cell shape. Addition of FN (20 mg/L) to fresh medium could inhibit the cell shape change induced by fresh medium. Microfilament and insoluble FN were disorganized by fresh medium. CONCLUSION: These results indicated that autocrine soluble FN of osteosarcoma MG-63 cells may be involved in cell shape maintaining.