Fig. 2

GMSC and GMSCExo block RASF cartilage invasion in the primary implant. A H&E-stained negative control cartilage showing no RASF invasion. B H&E-stained positive control cartilage showing deep RASF penetration throughout the tissue including perichondrocytic degradation, blue arrows, and large pannus formation, black arrows. C H&E-stained RASF-treated and GMSC exosome-treated cartilage showing no RASF invasion. D H&E-stained RASF-treated and GMSC-treated cartilage showing no RASF invasion. E Invasion depth demonstrates very deep penetration of the cartilage when treated with RASF alone. Treatment with either GMSC or GMSCExo blocks the invasion of the primary implant (mean ± SE, n = 5 for RASF alone and negative control, n = 10 for RASF + GMSC, n = 13 for RASF + GMSCExo, ***p < 0.0002; ****p < 0.0001). F Close-up images of the pannus structures. G Serial sections of RASF alone (positive control) treated cartilage showing expression of human MMP-14