Figure 8. Young and aging MSC-EVs expressed differential levels of miRNAs. (A and B) Young and aging MSC-EVs were isolated from supernatants of MSCs via ultracentrifugation and levels of miRNAs associated with macrophage polarization (let-7c, miR-223-5p, miR-155-3p, miR-127-3p, and miR-125b-5p) in MSC-EVs were analyzed via qRT-PCR. All miRNAs were standardized to U6 snRNA using standard ΔΔCt method. Data are presented as mean ± SEM, n = 4–8. *p < 0.05.