Fig. 11

Immunochemical analyses of hypoxia inducible factor (HIF)-1α in rabbit intervertebral discs four weeks after lumbar artery ligation. A: HIF-1α immunoreactivity was clearly detected in the nuclei and cytoplasm of the cells in the outer AF (oAF) (a, b, c, d), inner AF (iAF) (e, f, g, h) and nucleus pulpous (NP) (i, j, k, l) of both control (L2/3) (a, e, i) and ischemia (cranial (b, f, j), bilateral (c, g, k) and caudal (d, h, l)) discs. Bar: 100 μm. B: Percentage of HIF-1α immunoreactive cells in outer AF (oAF), inner AF (iAF) and nucleus pulpous (NP) of both control (L2/3) and ischemia (caudal, bilateral and cranial) discs. Two-way analysis of variance (ANOVA) revealed that the percentage of HIF-1α immunoreactive cells was significantly associated both with disc area (oAF, iAF, NP) and disc level (control and ischemia discs) at 4 weeks after the ligation of lumbar arteries (p < 0.05)