[Age-related thermodynamic and mechanical properties of the rat collagen]

The age peculiarities of cross-linking degree, thermodynamic and mechanic properties of rat tail tendon collagen fibres were investigated. It is shown that during the period from 1 to 3 months the melting temperature decreases and the enthalpy difference increases, from 3 to 24 months the melting temperature increases and the enthalpy difference decreases. The strength of fibres increases during the whole life. The maximal relative extension increases during the first 12 months and tends to decrease in after-life. The Young's module in the elastic deformation region decreases during the period from 1 to 3 months, then increases. It is shown tht those changes in fibre properties may be connected with the age dynamics of collagen cross-linking degree observed here: its decreasing during the period from 1 to 3 months and its following continuous increasing in after-life.