Roles of collagen cross-links and osteon collagen/lamellar morphotypes in equine third metacarpals in tension and compression tests.

Autor:	Skedros JG; University of Utah, Department of Orthopaedics, Salt Lake City, UT 84108, USA., Dayton MR; University of Colorado, Department of Orthopedics, Aurora, CO 80045, USA., Cronin JT; University of Utah, Department of Orthopaedics, Salt Lake City, UT 84108, USA., Mears CS; University of Utah, Department of Orthopaedics, Salt Lake City, UT 84108, USA., Bloebaum RD; University of Utah, Department of Orthopaedics, Salt Lake City, UT 84108, USA., Wang X; Department of Mechanical Engineering, University of Texas, San Antonio, TX 78249, USA., Bachus KN; University of Utah, Department of Orthopaedics, Salt Lake City, UT 84108, USA.; Research Service, Veterans Affair Medical Center, Salt Lake City, UT 84148, USA.
Jazyk:	angličtina
Zdroj:	The Journal of experimental biology [J Exp Biol] 2024 Jul 15; Vol. 227 (14). Date of Electronic Publication: 2024 Jul 24.
DOI:	10.1242/jeb.247758
Abstrakt:	Many bones experience bending, placing one side in net compression and the other in net tension. Because bone mechanical properties are relatively reduced in tension compared with compression, adaptations are needed to reduce fracture risk. Several toughening mechanisms exist in bone, yet little is known of the influences of secondary osteon collagen/lamellar 'morphotypes' and potential interplay with intermolecular collagen cross-links (CCLs) in prevalent/predominant tension- and compression-loaded regions. Paired third metacarpals (MC3s) from 10 adult horses were prepared for mechanical testing. From one MC3/pair, 5 mm cubes were tested in compression at several mid-shaft locations. From contralateral bones, dumbbell-shaped specimens were tested in tension. Hence, habitual/natural tension- and compression-loaded regions were tested in both modes. Data included: elastic modulus, yield and ultimate strength, and energy absorption (toughness). Fragments of tested specimens were examined for predominant collagen fiber orientation (CFO; representing osteonal and non-osteonal bone), osteon morphotype score (MTS, representing osteonal CFO), mineralization, porosity and other histological characteristics. As a consequence of insufficient material from tension-tested specimens, CCLs were only examined in compression-tested specimens (HP, hydroxylysylpyridinoline; LP, lysylpyridinoline; PE, pentosidine). Among CCLs, only LP and HP/LP correlated significantly with mechanical parameters: LP with energy absorption, HP/LP with elastic modulus (both r=0.4). HP/LP showed a trend with energy absorption (r=-0.3, P=0.08). HP/LP more strongly correlated with osteon density and mineralization than CFO or MTS. Predominant CFO more strongly correlated with energy absorption than MTS in both testing modes. In general, CFO was found to be relatively prominent in affecting regional toughness in these equine MC3s in compression and tension. Competing Interests: Competing interests The authors declare no competing or financial interests. (© 2024. Published by The Company of Biologists Ltd.)
Databáze:	MEDLINE
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