Optimal concentration of MSCs-Exo
After clarifying the therapeutic effect of MSCs-Exo, we used different concentrations of MSCs-Exo to find the optimal concentration for AR treatment. We used 4×106/mL, 4×107/mL, 4×108/mL, 4×109/mL, and 4×1010/mL exosomes for intranasal administration in AR mice (Figure 5A). We found that the effect was dose-dependent (Figure 5B–E). At a concentration of 4×106/mL, we observed basically no effect on the sneezing and rubbing events and inflammation-related indicators. At concentrations higher than 4×108/mL, no significant further improvement in the inflammatory symptoms of the mice was observed. This result suggests that the optimal concentration of MSCs-Exo to reduce allergic inflammation in mice is around 4×108/mL.