Thermal stability of collagen in naturally ageing and in vitro glycated rabbit tissues

the aim of the work was to compare glycation-related changes in thermal denaturation of collagen in naturally ageing and in vitro ribosylated tissues. samples of cornea, meniscus and achilles tendon from young adult and from ageing rabbits were compared. moreover, in vitro glycated samples (ribose, 100 mg ml−1, 14 days) were prepared for both age groups. collagen in tissues was characterized in terms of thermal denaturation parameters obtained from differential scanning calorimetry. the level of pentosidine and other fluorescent advanced glycation end products (ages) in the papain-digested tissue samples was evaluated using spectrofluorimetry (λex/em: 335/385 and 370/440 nm). in naturally ageing tissues, changes in properties of extracellular matrix collagen expressed in terms of parameters of thermal denaturation and fluorescent ages levels were tissue dependent and were related to differences in organization of matrix components. no signs of increased level of ages were found in the naturally ageing cornea, unlike in the tendon and meniscus. in vitro ribation proved by gains of fluorescent ages affected thermal stability of collagen in all tissues, both in young adult and in the ageing ones. the effects of ribation were considerably greater than the effects of natural ageing. the increase in denaturation temperature was similarly strong in all tissues and did not correlate with the increase in fluorescent ages. as a conclusion, parameters of collagen thermal denaturation are tissue and age dependent and an amount of fluorescent ages is not the only determinant of increasing thermal stability of glycated collagen.