Recurrent hypoxia/reoxygenation (H/R) stress mimicking acute vaso-occlusive crisis (VOCs) worsens bone structure in sickle cell mice. (A) Quantitative histomorphometry of the distal femur of healthy (AA) and sickle cell (SS) mice exposed to recurrent (Rec) acute VOCs without and with Zol treatment. Left panel: representative undecalcified section of distal femur stained with trichrome Goldner’s stain. Right panel: MSV, marrow star volume; NdN/TV, node number/tissue volume; NdN/Tm, node to termini ratio. Data are shown as mean ± SD (n = 6); P < .05 compared with healthy mice; °P < .05 compared with vehicle-treated mice. (B) Bone volume (BV)/tissue volume (TV), trabecular thickness, trabecular number, and trabecular separation in healthy (AA) and sickle cell (SS) mice exposed to recurrent (Rec) acute VOCs without and with Zol treatment. (C) N.Oc/TA, osteoclast tumber/tissue area; ES/BS, erosion surface/bone surface in AA and SS mice exposed to recurrent (Rec) acute VOCs without and with Zol. Data are shown as mean ± SD (n = 6); *P < .05 compared with healthy mice; °P < .05 compared with vehicle-treated mice.