Changes in collagen and elastin of the rat aorta induced by experimental diabetes and food restriction.

The biochemical and biomechanical properties of aortas from diabetic rats were investigated after a period of three months. Diabetes caused increased non-enzymatic glycosylation of lysine and hydroxylysine residues of collagen, whereas no changes were found in the reducible collagen cross-links. Although diabetes caused a reduction in the thickness of the aortic wall and a decrease in the dry weight and amount of collagen and elastin per mm2, no changes were found in the mechanical strength and stiffness of the wall. When the mechanical parameters were corrected for the decrease in dry weight, the tensile strength of the aortic wall was found to be increased compared with the control group. This increase in the stability of aortic collagen can be explained by formation of reactive carbonyl compounds from the glycosyllysines, resulting in stabile cross-links between the collagen molecules.