Characterization and cytological effects of a novel glycated gelatine substrate

Hyperglycemia in diabetes results in the glycation of long-lived proteins. Protein glycation leads to the formation of advanced glycation end products (AGEs), which are implicated in delayed wound healing and other diabetes-associated pathologies, one of which is periodontal disease. Research into the mechanisms by which glycated long-lived proteins such as collagen exert their effects can allow for the understanding of diabetic pathologies and the development of appropriate treatments. However, the high cost of purified protein can be a limitation for many laboratories around the world. The objective of this study was to develop a low-cost in vitro model of glycated gelatine as an alternative to the glycated collagen model. We investigated the glycation of gelatine type A, a denatured form of collagen, which is low-cost and abundantly available. In this study, gelatine was incubated for 7 days with ribose or methylglyoxal (MG). Cross-linking, autofluorescence and UV-Vis spectrophotometry assays were performed and indicated a dose-dependent linear increase in cross-linking and autofluorescence of gelatine by ribose and MG. MG produced more cross-linking compared to ribose at the same concentrations. The UV-Vis spectra of the glycated gelatines confirmed the presence of AGE fluorophores. Because diabetes is a risk factor for periodontal disease, the effect of the glycated substrates on the basic behaviour of human periodontal ligament (HPDL) cells was evaluated. Glycation dose dependently reduced HPDL attachment and cell spreading, indicating that the novel glycated gelatine substrate affects cell behaviour. These results show that gelatine glycated with ribose or MG can be used as low-cost in vitro models to study the effects of protein glycation on cell behaviour in diabetes and ageing.