UNLABELLEDThis experiment was aimed to study the effects of different concentrations of medroxyprogesterone acetate (MPA) on proliferation, migration and apoptosis of endothelial progenitor cells (EPCs) in vitro and to provide experimental evidence for the use of MPA as anti-angiogenesis drug. We separated EPCs from bone marrow of a beagle dog and identified the expression of progesterone receptor (PR) in EPCs by immunocytochemistry. Proliferation tests (MTT analysis) were performed with EPCs in response to different concentration of MPA every 24 h for 7 consecutive days, the growth curve of these EPCs was obtained then. The inhibition rates were also obtained from MTT assay performed with EPCs exposed to different concentration of MPA. The migration tests were performed with EPCs in response to different concentrations of MPA. The cell cycle and apoptosis of EPCs exposed to different concentrations of MPA were analyzed by use of flow cytometry.

RESULTSImmunohistochemical staining showed that EPCs were positive to PR. High concentration of MPA had significant inhibition effect on the growth of EPCs. This effect was time- and dose-dependent. But the low concentration of MPA had not have such effect, EPCs exposed to high concentration of MPA were found arrested in S phase, and the apoptosis rate increased. The migration ability of EPCs exposed to high concentration of MPA was also damaged.

CONCLUSIONHigh concentration of MPA can induce EPCs' apoptosis and inhibit their growth and migration. All these biological effects of MPA may be achieved through PR on EPCs.