Deletion of Vhl in osteocytes and mature osteoblasts results in increased cortical osteocyte apoptosis.

<p>(A) H&E-stained sections of the cortical bone from femurs of 6-week-old and 8-month-old CON and ΔVHL mice. Empty osteocyte lacunae (arrows) can be observed in the sections obtained from the ΔVHL mice; all the osteocyte lacunae are filled with cells, as seen in the sections obtained from the CON mice. (B) Quantification of the empty osteocyte lacunae in the cortical bones of femurs from 6-week-old to 8-month-old CON and ΔVHL mice.(C) TUNEL staining of cortical bone at the diaphyses from femurs of CON and ΔVHL mice at 6 weeks and 8 months of age. (D) Frequency of TUNEL-positive lacunae. The number of TUNEL-positive lacunae was counted in mice at 6 weeks to 8 months of age, and was presented as a percentage of the total number of lacunae in the cortical bone of femurs. (E) Representative TEM images of osteocytes in the femoral midshaft. (F) Polarized microscopy of cortical bone at diaphyses of the femurs obtained from 8-month-old CON and ΔVHL mice. (G) High-power TEM images of Collagen fibrils (n = 6–9 mice for each genotype *** <i>p</i> < 0.001).