Figure 5. Immunocytochemical analysis of the proliferating (Ki67 positive) cell fraction. (A) Representative microphotographs of the immunofluorescently labeled MSCs with the Ki67 antibody (Ki67+ cells are marked with the arrows). (B) Changes in the percentage of the proliferating cells depending on the passage number in the control and irradiated MSCs. Mean values derived from at least three independent experiments are shown. Error bars show SE.