Fig. 3

Immunofluorescence of CGRP⁺ and exosomes uptake and quantitative analysis of spinal pain-related behavior tests among different treatment groups. (A–B) The hind-paw withdrawal frequency (PWF) responding to the Von-Frey filaments with 0.7 mN and 3,9 mN; (C) Pressure hyperalgesia of the lumbar spine. (D) Representative images of immunofluorescence of CGRP+ (A marker of nociceptor nerves, Red-Alexa Fluor® 594) in subchondral bone of LFJ in vivo under 40x objective lens in 4, 6 and 8 weeks. Scale bar, 100 μm. (E) Quantitative analysis of the percentage of CGRP+ area in subchondral bone of LFJ. (F) Representative image of immunofluorescence of PKH26 labeled Hypo-ADSCs-Exo (PKH26⁺, Red) through tail vein administration in facet joint cartilage and subchondral bone of LFJ in vivo. The yellow arrows indicate that Hypo-ADSCs-Exo by administration of tail vein were internalized in cartilage zone and subchondral bone area. Scale bar, 100 μm. All images were captured under 40x objective lens. All data are shown as the mean ±standard deviation (SD). *p ＜ 0.05, **p ＜ 0.01, compared with PBS treated group mice, ^#p ＜ 0.05, ^##p ＜ 0.01, compared with ADSCs-Exo mice. n.s., non-significant. n=6 per group