Fig. 4

MSC-EVs were labeled with DiR to evaluate the optimal time of administration during ALI. A Study design of the experiment including intravenous delivery of DiR MSC-EVs (15 μg) at 0.5 h, 5 h, 10 h or 24 h after disease induction, followed by live and ex vivo fluorescence imaging 0.5 h after EV administration. B Lung and C liver fluorescence as measured by radiant efficiency. Optimal timing of EV administration for lung accumulation was found to be at 24 h after disease induction. Data are presented as mean ± SEM, N = 3 per group, *P < 0.05