p-Dimethylaminobenzaldehyde-reactive substances in tail tendon collagen of streptozotocin-diabetic rats: temporal relation to biomechanical properties and advanced glycation endproduct (AGE)-related fluorescence

Abstract

In the present work, pepsin digests of tail tendons from streptozotocin-diabetic rats were found to contain material that reacted rapidly at room temperature with p-dimethylaminobenzaldehyde (Ehrlich's reagent) to give an adduct with an absorbance spectrum characteristic of the Ehrlich chromogen of pyrrolic nature determined in ageing collagens. A significant correlation of the Ehrlich adduct with tendon mechanical strength and collagen fluorescence characteristic of advanced glycation endproducts was observed. Collagen content of the Ehrlich-positive material was found to be significantly elevated in tendons of diabetic rats compared with age-matched healthy controls. The results indicate that the p-dimethylaminobenzaldehyde-reactive pyrrole moieties may contribute to the increased cross-linking of diabetic matrix collagen. Profound inhibitory effect of aminoguanidine was observed, underlining the role of non-enzymatic mechanisms of advanced glycation in pyrrolisation and cross-linking of collagen exposed to hyperglycaemia. It is hypothesised that quantification of the p-dimethylaminobenzaldehyde-reactive material in matrix collagen may provide a tissue measure of integrated hyperglycaemia over prolonged periods of time. Further research is to assess the significance of p-dimethylaminobenzaldehyde-reactive substances in diabetic collagen tissues and to reveal their relationship to enzyme-mediated physiological pyrrolisation of ageing collagens.

Alagebrium inhibits neointimal hyperplasia and restores distributions of wall shear stress by reducing downstream vascular resistance in obese and diabetic rats

“…Vessel segments analyzed for ARCC underwent pepsin digestion (43). Briefly, vessel segments were lyophilized for Ͼ8 h to obtain their dry weight.…”

LR-90 a new advanced glycation endproduct inhibitor prevents progression of diabetic nephropathy in streptozotocin-diabetic rats

“…Total pepsin digestion was done as described previously [46]. Collagen samples of 10 mg from individual rats were digested with pepsin (50 µg/ml in 0.5 mol/l acetic acid) for 24 h at 37°C.…”

Diabetes Alters Mechanical Properties and Collagen Fiber Re-Alignment in Multiple Mouse Tendons

“…4 However, the mechanical function of the tendons in this diabetic mouse model has not yet been studied. While studies have revealed the presence of advanced glycation end-products in tendons of diabetic animal models, 28, 29, 33 it is also still unclear if there are changes in other extracellular matrix proteins that could cause changes in mechanical properties, such as proteoglycans or glycosaminoglycans (GAGs). In addition, collagen fiber realignment in response to load, which is indicative of small structural alterations in the tissue, has also not been studied in diabetic tendons.…”