The influence of non-enzymatic glycosylation and formation of fluorescent reaction products on the mechanical properties of rat tail tendons.

Mechanical stability was examined in rat tail tendons after in vitro incubation in glucose at pH 7.4 using buffer systems of either phosphate or tris(hydroxymethyl)aminomethan. In the phosphate buffer system glucose and fluorescent compounds were found to be attached to the collagen molecules and the maximum 'stress' of the tendons was increased. In the tris(hydroxymethyl)aminomethan buffer system glucose was attached to the collagen molecules, but only small amounts of fluorescent compounds were attached to the collagen molecules and no changes in mechanical parameters were recorded. Initial incubation of tendons in a high concentration of glucose followed by incubation in either phosphate or tris(hydroxymethyl)aminomethan buffer solutions resulted in equal attachment of glucose to the collagen, but only the collagen reincubated in phosphate buffer developed a relatively high amount of fluorescent compounds and an increase in maximum mechanical 'stress' compared to the collagen reincubated in tris(hydroxymethyl)aminomethan buffer. This shows that the non-enzymatic glycosylation per se does not necessarily influence the mechanical properties of collagen. Additional reactions like transformation of glucose into fluorescent compounds or browning reaction products by Maillard's reaction seem to be essential.