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. 2018 Jul 2;17(5):e12800. doi: 10.1111/acel.12800

Figure 4.

Figure 4

Reduced nucleus pulposus cell viability and impaired autophagy in FOXO‐deficient intervertebral disks. (a) Terminal deoxynucleotidyl transferase (TdT) dUTP Nick‐End Labeling (TUNEL) staining in lumbar intervertebral disks (IVD) isolated from Col2a1Cre−/− and Col2a1Cre‐FOXO KO mice at 4 and 6 months of age (n = 5 mice per group). Lower panels show quantification of TUNEL‐positive cells in the NP and EP. No positive cells were observed in the AF. NP: nucleus pulposus; AF: annulus fibrosus; EP: endplate. Magnification bar = 100 µm. (b) TUNEL staining in lumbar IVD from AcanCreER−/− and AcanCreER‐FOXO KO mice at 12 months of age (n = 5 mice per group). Lower panels show quantification of TUNEL‐positive cells in the NP and EP. (c) Gene expression analysis of homeostatic genes in NP from Col2a1Cre−/− and Col2a1Cre‐FOXO KO mice at 2 months of age (n = 4 mice per group). (d) Immunofluorescence staining for LC3 in the NP of lumbar IVD isolated from Col2a1Cre−/− and Col2a1Cre‐FOXO KO mice at 4 months of age (n = 5 mice per group) shows a decrease in immunostained cells in FOXO‐deficient NP cells. Right panel shows quantification of LC3 puncta per cell. Values shown are mean ± SD. Statistical comparisons were assessed by an unpaired, two‐tailed t‐test after testing for equal variance using an F‐test. Values are mean ± SD. *p < 0.05