Abstract: AIM:To study the effect of arsenic trioxide (ATO) on the proliferation and apoptosis of mesenchymal stem cell (MSC) of human bone marrow in vitro.METHODS:MSC from healthy volunteers were cultured in vitro and subcultured for three generations. After being identified, the cells were cultured with different concentrations of ATO (1, 5, 10 μmol/L). After 24, 48 and 72 h, the morphological changes of MSC were observed by HE staining; the inhibition of proliferation was measured by MTT assay, and cell apoptosis was evaluated by flow cytometry.RESULTS:After treatment of ATO, partial cells presented characteristic morphological changes. ATO inhibited the growth of MSC in a concentration-and timedependent manner. Flow cytometry analysis showed that ATO induced apoptosis of MSC, and the percentage of apoptotic cells increased as the concentration increased and time elapsed. While the cells were treated with ATO (10 μmol/L) for 72 h, the percentage of apoptotic cells was 68. 37% ±2. 93% .CONCLUSION: ATO can inhibit proliferation of MSC and promote its apoptosis in vitro.

Key words: arsenic trioxide, mesenchymal stem cell, proliferation, apoptosis