Fig. 3.

The effect of cell density on exosome secretion from hBM-MSCs. A Schematic illustration of the experimental groups. hBM-MSCs were cultured in monolayer at normal density (2D) or high density (2D-H), as described in Materials and Methods. B Gross morphology of 2D-MSCs and 2D-H-MSCs are shown at 1, 3, and 5 days of culture. Scale bar: 60 μm. c The production efficiency of exosomes derived from the 2D-MSCs and 2D-H-MSCs. The amounts of exosomes obtained from 1 × 10⁵ cells are presented for each group. Data are presented as the mean and SD from three independent experiments. *p  < 0.05 and **p  < 0.01 by t test. *** hBM-MSCs: human bone marrow-mesenchymal stem cells, 2D: two-dimensional, ANOVA: analysis of variance