Blood vessel and osteocyte networks concurrently rearrange during bone maturation and decline during aging in the femur of male mice

1. Aging (Albany NY). 2025 Aug 22;17(8):2089-2112. doi: 10.18632/aging.206302.
Epub 2025 Aug 22.

Blood vessel and osteocyte networks concurrently rearrange during bone
maturation and decline during aging in the femur of male mice.

Palmier M(1), Maître M(2), Doat H(2), Lesté-Lasserre T(2), Boiziau C(1), Maurel
DB(1).

Author information:
(1)Inserm, University of Bordeaux, BioTis Laboratory UMR 1026, Bordeaux 33000,
France.
(2)Inserm, University of Bordeaux, Neurocentre Magendie UMR 1215, Bordeaux
33000, France.

While blood vessels and osteocytes have been studied independently, their
simultaneous changes with age remain undescribed. Our objective was to
investigate the age-related evolution of both osteocyte and blood vessel
networks in mouse cortical bone, and to assess the associated effects on
osteocyte markers and oxygen intracellular levels. We analyzed femurs of male
Flk1-GFP mice from growing, mature, middle-aged, and aged groups with techniques
such as laser microdissection followed by RT-qPCR, tissue clearing and 3D
fluorescence imaging. In the mature animals – when the cortical bone was thicker
than in the growing animals – the osteocyte density, the number of dendrites per
osteocyte and the blood vessel density were lower. This was associated with a
reduced expression of Pdpn and with a smaller fraction of osteocytes exhibiting
low intracellular oxygen. In aged animals – when cortical bone was thinner than
in mature animals – the number of dendrites per osteocyte and the blood vessel
density were lower. This was associated with a reduced Gja1 (Cx43) expression.
Our results suggest that changes in the osteocyte network during maturation and
aging are led by distinct mechanisms, and that the cortical bone blood vessels
are not the main source of oxygen for osteocytes.

DOI: 10.18632/aging.206302
PMCID: PMC12422823
PMID: 40848274 [Indexed for MEDLINE]

Conflict of interest statement: CONFLICTS OF INTEREST: The authors declare no
conflicts of interest related to this study.

Auteurs Bordeaux Neurocampus