Hypoxia may be associated with alterations in bone remodeling, but the published results
are contradictory. The aim of this study was to characterize the bone morphometry changes subject
to hypoxia for a better understanding of the bone response to hypoxia and its possible clinical
consequences on the bone metabolism. This study analyzed the bone morphometry parameters by
micro-computed tomography ( CT) in rat and guinea pig normobaric hypoxia models. Adult male
and female Wistar rats were exposed to chronic hypoxia for 7 and 15 days. Additionally, adult male
guinea pigs were exposed to chronic hypoxia for 15 days. The results showed that rats exposed to
chronic constant and intermittent hypoxic conditions had a worse trabecular and cortical bone health
than control rats (under a normoxic condition). Rats under chronic constant hypoxia were associated
with a more deteriorated cortical tibia thickness, trabecular femur and tibia bone volume over the
total volume (BV/TV), tibia trabecular number (Tb.N), and trabecular femur and tibia bone mineral
density (BMD). In the case of chronic intermittent hypoxia, rats subjected to intermittent hypoxia
had a lower cortical femur tissue mineral density (TMD), lower trabecular tibia BV/TV, and lower
trabecular thickness (Tb.Th) of the tibia and lower tibia Tb.N. The results also showed that obese
rats under a hypoxic condition had worse values for the femur and tibia BV/TV, tibia trabecular
separation (Tb.Sp), femur and tibia Tb.N, and BMD for the femur and tibia than normoweight rats
under a hypoxic condition. In conclusion, hypoxia and obesity may modify bone remodeling, and
thus bone microarchitecture, and they might lead to reductions in the bone strength and therefore
increase the risk of fragility fracture.
