Water flow through bone: Neutron tomography reveals differences in water permeability between osteocytic and anosteocytic bone material. (December 2022)

• Record Type: Journal Article
• Authors: Silveira, Andreia; Kardjilov, Nikolay; Markötter, Henning; Longo, Elena; Greving, Imke; Lasch, Peter; Shahar, Ron; Zaslansky, Paul
• Is Part Of: Materials & design. Volume 224(2022)
• Publication Date: 2022-12
• Subjects: Bone porosity -- Anosteocytic bone -- Water permeability -- Neutron tomography -- Proteoglycans; CdC Caudal cone -- Cm Centrum middle -- CrC Cranial cone -- D2O Deuterated-water -- ECM Extracellular matrix -- GAGs Glycosaminoglycans -- H2O Water -- LCN Lacunar-canalicular network -- N-μCT Neutron tomography -- PGs Proteoglycans -- μCT Micro-computed X-ray tomography; Materials -- Periodicals; Engineering design -- Periodicals; Matériaux -- Périodiques; Conception technique -- Périodiques; Electronic journals; 620.11
• DOI: 10.1016/j.matdes.2022.111275
• Languages: English
• ISSNs: 0264-1275

Abstract

Graphical abstract: Highlights: Anosteocytic bone material is more water permeable than osteocytic bone material. In osteocytic zebrafish bone, water flow appears to be confined to the lacunar-canalicular network. Anosteocytic medaka bone is water permeable and containes far less proteoglycans. 3D correlation of neutron and X-ray tomographies with micron resolution reveals water diffusion across the bone matrix. Abstract: Vertebrate bones are made of a nanocomposite consisting of water, mineral and organics. Water helps bone material withstand mechanical stress and participates in sensation of external loads. Water diffusion across vertebrae of medaka (bone material lacking osteocytes) and zebrafish (bone material containing osteocytes) was compared using neutron tomography. Samples were measured both wet and following immersion in deuterated-water (D2 O). By quantifying H + exchange and mutual alignment with X-ray µ CT scans, the amount of water expelled from complete vertebra was determined. The findings revealed that anosteocytic bone material is almost twice as amenable to D2 O diffusion and H2 O exchange, and that unexpectedly, far more water is retained in osteocytic zebrafish bone. Diffusion in osteocytic bones (only 33 % – 39 % water expelled) is therefore restricted as compared to anosteocytic bone (∼ 60 % of water expelled), presumably because water flow is confined to the lacunar-canalicular network (LCN) open-pore system. Histology and Raman spectroscopy showed that anosteocytic bone contains less proteoglycans than osteocytic bone. These findings identify a previously unknown functional difference between the two bone materials. Therefore, this study proposes that osteocytic bone retains water, aided by non-collagenous proteins, which contribute to its poroelastic mechano-transduction of water flow confined inside the LCN porosity.