Prevent Disease.com - 'Sacrificial' Bonds Protect Bones From Breaking



		'Sacrificial' Bonds Protect Bones From Breaking Excerpt By Suzanne Rostler, Reuters Health NEW YORK (Reuters Health) - Bones may owe their toughness and resilience to tiny bonds embedded in collagen, US researchers report. Their study found that collagen, the main component of bone, contains ``sacrificial bonds'' that are broken when there is an impact from a bump or stretch. These bonds absorb the force and may even break so that the bone is left unharmed. When the impact subsides, some of these bonds repair themselves. ``Our results suggest that sacrificial bonds within collagen rupture, and thereby dissipate the energy of an impact before permanent damage is done,'' Dr. James B. Thompson, the study's lead author, told Reuters Health. ``Because these bonds can reform, they can dissipate energy again in response to later impacts.'' The results of the study are reported in the December 13th issue of Nature. Bone is composed of brittle mineral crystals that give the skeleton its rigid structure. Why bones are so resilient and able to resist the weakening effect of scratches and holes, however, has remained unclear. ``A great deal is known about bone's mechanical properties. For example, changes in the structure or bonding of collagen within bone have been associated with reduced bone strength,'' said Thompson, from the University of California, Santa Barbara, in an interview. ``Our findings offer the beginnings of a molecular understanding of how collagen lends strength to bone.'' The researchers used an atomic force microscope to measure the force required to stretch collagen molecules as well as the force required to make indentations into bones. Their study revealed that bone contains a substance that houses these bonds, which dissipates the force of an impact. Furthermore, the time that it takes for these bonds to recover correlates with the time it takes for bones to recover their resilience. SOURCE: Nature 2001;414:773-776. Reference Source 89 For more information on how to prevent other diseases, use PreventDisease.com's "Quick Prevention Resources".