Fig. 4 | Bone Research

Fig. 4

From: Akkermansia muciniphila attenuates intervertebral disc degeneration via extracellular vesicle-mediated delivery of the effector protein B2UKX5

Fig. 4The alternative text for this image may have been generated using AI.

Supplementation of Akk and Akk-EVs attenuates IVDD in multiple in vivo models. a Representative ex vivo fluorescence images of L2-6 lumbar intervertebral discs 24 h after intravenous injection of DiR-labeled Akk-EVs in mice. Scale bar: 3 mm. b Quantitative analysis of mean fluorescence intensity across L2-6 in intervertebral discs. n = 3 per group. c Schematic of the experimental protocol for Akk and Akk-EVs treatment in needle puncture mice. d Representative T2-weighted MRI images of the C8-9 caudal spine. Scale bar: 1 mm. e Statistical analysis of Pfirrmann grading for the C8-9 caudal segment. n = 8 per group. Representative DR images (f) and micro-CT 3D reconstruction images (g) of the caudal spine. Scale bar: 1 mm. h DHI after 12 weeks of needle puncture at the C8-9 caudal segment. n = 8 per group. Representative H&E (i) and SO/FG (j) stained images showing the macroscopic morphology of the disc, NP, and AF in the C8-9 segment. Scale bars: 200 μm (Disc) or 50 μm (NP, AF). k Histological scores for the C8-9 segment. n = 8 per group. l Schematic of the experimental protocol for Akk and Akk-EVs treatment in naturally aging mice. m Representative T2-weighted MRI images of the lumbar spine in mice. Scale bar: 1 mm. n Statistical analysis of the average Pfirrmann grade in the L1-S1 lumbar disc segments. n = 9–14 per group. o Representative micro-CT 3D reconstruction images of the L5-6 lumbar disc segments. Scale bar: 1 mm. p Statistical analysis of the mean DHI in the L2-6 lumbar disc segments. n = 8–10 per group. q, r Representative images of H&E (q) and SO/FG (r) staining showing the macroscopic morphology of intervertebral disc (Disc), nucleus pulposus (NP), annulus fibrosus (AF), and endplate (EP) in the L5-6 lumbar disc segment. Scale bars: 200 μm (Disc) or 50 μm (NP, AF, EP). s Statistical analysis of histological scores for each lumbar segment (L2-6). n = 8–10 per group. t Representative IF images showing the expression of COL2, ACAN, and MMP13 in the L5-6 lumbar intervertebral discs. Scale bar: 200 μm. u Quantitative analysis of COL2, ACAN, and MMP13 expression. n = 8–10 per group. Data are presented as mean ± SD. Statistical significance was determined by unpaired Student’s t-test (b) or one-way ANOVA followed by Bonferroni post hoc test (e, h, k, n, p, s, u)

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