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[Effects of constant magnetic fields on proliferation and migration of endothelial progenitor cells under rapamycin intervention: experiment with rats].

OBJECTIVE
To investigate the effects of constant magnetic field (CMF) on proliferation and migration of bone marrow-derived endothelial progenitor cells (EPCs) under rapamycin intervention.


METHODS
EPCs were isolated from rat bone marrow by density gradient centrifugation and cultured on fibronectin-coated dishes. Six days later the attached cells were divided into 5 groups: control group, rapamycin (1 ng/ml) group, and 3 rapamycin + CMF groups (treated with CMF of the doses 0.1 mT, 0.5 mT, and 1.0 mT respectively). Samples were collected 24 hours after incubation. Cell proliferation was measured by MTT chromatometre. EPC migration was detected with modified Boyden chamber assay.


RESULTS
The EPC proliferation ability of the rapamycin group, expressed by absorbance, was (0.252 +/- 0.006), significantly lower than that of the control group [(0.328 +/- 0.025), P < 0.05]. The number of migrating EPC was (31 +/- 3) cells, significantly lower than that of the control group [(48 +/- 5), P < 0.05]. The EPC proliferation ability of the rapamycin + CMF 0.5 mT and 1.0 mT groups, expressed by absorbance, were (0.278 +/- 0.008) and (0.280 +/- 0.010) respectively, both significantly higher than that of the control group (both P < 0.05). The migrating EPC number of the rapamycin + CMF 0.5 mT and 1.0 mT groups were (37 +/- 3) and (38 +/- 4) respectively, both significantly higher than that of the control group (both P < 0.05).


CONCLUSION
CMF of the doses of 0.5 mT and 1.0 mT antagonizes the effects of rapamycin on EPCs, increasing the proliferation and migration of EPCs.