Fig. 5
Combined pretreatment with hypoxia and TXL elevated the expression level of CXCR4 and increased the retention rate of transplanted MSCs. Combined pretreatment with hypoxia and TXL elevated the retention rate of the transplanted MSCs in infarcted myocardium (A, B) (n = 5). Scale bar = 50 μm. Combined pretreatment with hypoxia and TXL significantly elevated both the mRNA (n = 4) (C) and protein levels (n = 5) (D, E) of CXCR4 in MSCs. After 24 h of incubation, PKH-26-labeled exosomes could be taken up by MSCs (F). Under H/SD conditions, exosomes effectively protected MSCs against apoptosis (G, H) (n = 4). Representative images of western blotting (I, K) and quantitative data (J, L) of the protein levels of Bcl-2 and cleaved-caspase 3 (n = 4). Statistical data were analyzed using one-way ANOVA followed by Tukey’s test with data shown as mean ± SEM. &&p < 0.05, &&p < 0.01, &&&p < 0.001, &&&&p < 0.0001 versus MSC group; #p < 0.05, ##p < 0.01, ###p < 0.001, ####p < 0.0001 versus Exo + MSC group; αp < 0.05 versus Exo + MSCH group; δϕϕϕϕp < 0.0001 versus MSCH group; εεεεp < 0.0001 versus MSCT group; μp < 0.05 versus Exo + MSCT group; *p < 0.05, **p < 0.01 versus H/SD group; $p < 0.05 versus Exosome (ultra) group