Mesenchymal Stem Cell-Derived Exosomes Induced by IL-1β Attenuate Urethral Stricture Through Let-7c/PAK1/NF-κB-Regulated Macrophage M2 Polarization.

These results support a role for let-7c-containing Exo-MSCsIL-1β in reducing urethral stricture via inhibition of PAK1-NF-κB signaling, M2 macrophage polarization, and differentiation of urethral myofibroblasts.