Fig 1: GDF15 pretreatment augmented paracrine effects of MSCs. A Schematic showing the experiments for assaying the paracrine effect of MSCs with or without GDF15. B Representative images of tube formation in HUVECs treated with DMEM, MSC-CM or GDF15-MSC-CM. Scale bar = 100 μm. C Quantification of tube formation in HUVECs treated with DMEM, MSC-CM or GDF15-MSC-CM. D The concentration of VEGF, EGF and bFGF in MSC-CM and GDF15-MSC-CM was determined by ELISA assay. E Representative images of the apoptotic NCMs treated with DMEM, MSC-CM or GDF15-MSC-CM under SD/H condition. Scale bar = 200 μm. F Quantification of the apoptotic rate of NCMs treated with DMEM, MSC-CM or GDF15-MSC-CM under SD/H condition. Data are expressed as the mean ± SEM. N = 3 biological replicates for each group. *p < 0.05; **p < 0.01; ***p < 0.001