Exosomes from umbilical cord mesenchymal stromal cells promote the collagen production of fibroblasts from pelvic organ prolapse

Figure 4 Identification and internalization of human umbilical cord mesenchymal stromal cell-derived exosomes. A: TEM was utilized to obtain representative images of human umbilical cord mesenchymal stromal cell-derived exosome (hucMSC-Exo) (scale bar: 200 μm); B: NTA of the size distribution and concentration of hucMSC-Exo; C: Western blot analysis for the detection of the hucMSC-Exo surface markers heat shock protein 70, TSG101, and CD81; D: Observation of PKH-26-hucMSC-Exo internalization by fibroblasts via both fluorescence microscopy and laser confocal microscopy; E: The 3D image of hucMSC-Exo internalized by fibroblasts; F and G: The median fluorescence intensity (F) and quantification (G) of hucMSC-Exo uptaken by fibroblasts with 4 μg/mL and 6 μg/mL after treatment for 24, 48, and 72 h via FCM. DAPI is blue, PKH26 is red, F-actin is green in D, Wheat germ agglutinin is green in E. Scale bars: 50 μm and 25 μm. ^aP < 0.05; ^bP < 0.01; ^dP < 0.0001. HSP: Heat shock protein; Exo: Exosome.