Fig. 1

VAP partially rescue β-catenin(ex3)^Col2CreER mice facet joint-like phenotype. OA model group showed osteophytes formation (red arrow) and disc space narrowing (yellow arrow) on L1-L4 (a). However, the osteophyte formation around the lumbar intervertebral disc decreased in VAP different dosage groups, especially in 4th lumbar vertebral (b). Micro-CT (μCT) data show VAP partially rescue β-catenin(ex3)^Col2CreER mice lumbar disc osteophyte formation. Histologic results demonstrated that facet joint phenotype of the WT group is normomorph, the articular cartilage surface is smooth and complete, cartilage layer is clear, chondrocyte under the articular cartilage arranged orderly. Histology of model group displayed severe loss of facet joint cartilage tissue compare with wild type group, part of the cartilage surface appear damage, cartilage layer dye and thinning. After treat with VAP, the number of facet joint growth plate chondrocytes increase. Representative photos show the morphology using microscopy (c). Histomorphometry analyze the articular cartilage area of each histology section. Alcian blue-stained areas were outlined on projected images to determine facet joint’s articular cartilage area. * P < 0.05,** P < 0.01 vs Control group; ^#P < 0.05,^##P < 0.01 vs OA group. Data were expressed as mean ± SD. The results indicate VAP may increase FJ articular cartilage area (d)