Molecular Basis for Elastic Energy Storage in Mineralized Tendon

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• 作者：Frederick H. Silver ; Joseph W. Freeman ; Istvan Horvath ; and William J. Landis
• 刊名：Biomacromolecules
• 出版年：2001
• 出版时间：September 2001
• 年：2001
• 卷：2
• 期：3
• 页码：750 - 756
• 全文大小：197K
• 年卷期：v.2,no.3(September 2001)
• ISSN：1526-4602

文摘

Animals store elastic energy in leg and foot tendons during locomotion. In the turkey, much of the locomotiveforce generated by the gastrocnemius muscle is stored as elastic energy during tendon deformation. Littleenergy storage occurs within the muscle. During growth of some avians, including the turkey, leg tendonsmineralize in the portions distal to the attached muscle and show increased tensile strength and modulus asa result. The purpose of this study is to test the hypothesis that the degree of elastic energy storage inmineralizing turkey tendon is directly related to the tendon mineral content. To test this hypothesis, thestress-strain behavior of tendons was separated into elastic and viscous components. Both the elastic springconstant and the elastic energy stored, calculated up to a strain of 20%, were found to be proportional totendon mineral content. It is concluded that mineralization is an efficient means for increasing the amountof elastic energy storage that is required for increased load-bearing ability needed for locomotion of adultbirds. Examination of molecular models of the hole region, where mineralization is initiated within thecollagen fibril, leads to the hypothesis that elastic energy is stored in the tendon by direct stretching of theflexible regions. Flexible regions within the collagen molecule fall within the positively stained bands ofthe collagen D period. It is proposed that mineralization increases the stored elastic energy by preventingflexible regions within the positively stained bands from stretching. These observations suggest thatmineralization begins in the hole region due to the large number of charged amino acid residues found inthe d and e bands.