A scanning force microscope (SFM; Nanoscope III) equipped with a Contact Mode Head was used for imaging. Band interval, diameter and depth of D-band gap were measured in non-diabetic and diabetic tail tendon fibrils and in fibrils incubated with glucose (0.5 M for 2 weeks). Fructosamine was determined in the tendon fibrils by a colorimetric method and pentosidine was evaluated in acid-hydrolyzed samples by coupled reverse phase-ionic exchange column HPLC. Results. Incubated fibrils revealed modifications in radius (228 ± 5 nm) and gap depth (3.65 ± 0.10 nm) that closely reproduce diabetes-induced damage (236 ± 3 and 3.20 ± 0.04 nm respectively) and were significantly different from the pattern seen in non-diabetic fibrils (151 ± and 2.06 ± 0.03 nm; p < 0.001). Both fructosamine and pentosidine were higher in diabetic (3.82 ± 1.43 nmol/mg and 2.23 ± 0.24 pmol/mg collagen respectively) and in glucose-incubated fibrils (9.27 ± 0.55 nmol/mg and 5.15 ± 0.12 pmol/mg collagen respectively) vs non-diabetic tendons (1.29 ± 0.08 nmol/mg and 0.88 ± 0.11 pmol/mg collagen respectively; p < 0.01); during the time course of incubation, an early increase in fructosamine was seen, whereas pentosidine increased later. The D-band parameter was similar in all three groups, indicating that axial organization is not modified by non-enzymatic glycation.
Scanning force microscope reveals structural alterations in diabetic rat collagen fibrils: role of protein glycation
ODETTI, PATRIZIO;ROLANDI, RANIERI;TRAVERSO, NICOLA;COTTALASSO, DAMIANO;PRONZATO, MARIA ADELAIDE;MARINARI, UMBERTO
2000-01-01
Abstract
A scanning force microscope (SFM; Nanoscope III) equipped with a Contact Mode Head was used for imaging. Band interval, diameter and depth of D-band gap were measured in non-diabetic and diabetic tail tendon fibrils and in fibrils incubated with glucose (0.5 M for 2 weeks). Fructosamine was determined in the tendon fibrils by a colorimetric method and pentosidine was evaluated in acid-hydrolyzed samples by coupled reverse phase-ionic exchange column HPLC. Results. Incubated fibrils revealed modifications in radius (228 ± 5 nm) and gap depth (3.65 ± 0.10 nm) that closely reproduce diabetes-induced damage (236 ± 3 and 3.20 ± 0.04 nm respectively) and were significantly different from the pattern seen in non-diabetic fibrils (151 ± and 2.06 ± 0.03 nm; p < 0.001). Both fructosamine and pentosidine were higher in diabetic (3.82 ± 1.43 nmol/mg and 2.23 ± 0.24 pmol/mg collagen respectively) and in glucose-incubated fibrils (9.27 ± 0.55 nmol/mg and 5.15 ± 0.12 pmol/mg collagen respectively) vs non-diabetic tendons (1.29 ± 0.08 nmol/mg and 0.88 ± 0.11 pmol/mg collagen respectively; p < 0.01); during the time course of incubation, an early increase in fructosamine was seen, whereas pentosidine increased later. The D-band parameter was similar in all three groups, indicating that axial organization is not modified by non-enzymatic glycation.
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