There is a lack of quantitative and non-invasive clinical biomechanical assessment tools for
diabetic foot ulcers. Our previous study reported that the indentation stiffness measured by an optical coherence tomography-based air-jet indentation system in a non-contact and non-invasive manner may reflect the tensile properties of diabetic
wounds. As the tensile properties are known to be contributed by
type I collagen, this study was aimed to establish the correlations between the indentation stiffness, and
type I collagen abundance and organisation, in order to further justify and characterise the in vivo indentation stiffness measurement in diabetic
wounds. In a male
streptozotocin-induced diabetic rat model, indentation stiffness, and
type I collagen abundance and organisation of excisional
wounds were quantified and examined using the optical coherence tomography-based air-jet indentation system and
picrosirius red polarised light microscopy, respectively, on post-wounding days 3, 5, 7, 10, 14, and 21. The results showed significant negative correlations between indentation stiffness at the
wound centre, and the
collagen abundance and organisation. The correlations between the indentation stiffness, as well as
collagen abundance and organisation of diabetic
wounds suggest that the optical coherence tomography-based air-jet indentation system can potentially be used to quantitatively and non-invasively monitor diabetic wound healing in clinical settings, clinical research or preclinical research.