Fig. 3: AGEs modulate collagen architecture and network connectivity, leading to enhanced viscoelasticity in livers and 3D hydrogels.
From: Matrix viscoelasticity promotes liver cancer progression in the pre-cirrhotic liver
a, Quantification of insoluble collagen (from left to right, n = 6, 6, 10, 5 and 5). b,c, SHG microscopy images of decellularized liver ECMs (b) (bundles, red arrows) and collagen hydrogels (c). Fibre lengths (CT-Fire) and fibre–fibre angles (ImageJ) were assessed (three mice or gels per group, five images per mouse or gel). d,e, Collagen hydrogels from c were assessed using rheometry for stiffness (d) and viscoelasticity (e), expressed as τ1/2 (the timescale at which stress is relaxed to half its original value). n = 5. f, Schematic of the collagen/IPN hydrogel. The diagram was adapted from ref. 16, under a Creative Commons licence CC BY 4.0. g, Confocal reflectance microscopy of collagen fibres after AGE ± ALT-711 exposure. h–j, Insoluble collagen (h; n = 5), fibre lengths (i; CT-Fire) and angles (j; ImageJ) in the IPN gels. Data are from three images per gel, three gels per group. k, Representative stress relaxation curves from IPN gels. l–o. Rheometry of IPN gels testing stiffness (l; storage modulus) and viscoelasticity (m–o), showing the loss tangent (m) and stress relaxation (stress relaxation curves (n) and τ1/2 (o)) are shown. n = 6. p, Simulation modelling. A matrix structure consisting of individual fibrils (3 μm length) without (left) or with (right) bundlers connecting the ends of fibrils at θ = 10°. q, After a matrix is assembled, it is deformed by 20% shear strain. r, Stress relaxation is measured using the two matrices shown in p. s,t, Stress relaxation was studied using matrices with different bundle length (LB) with θ = 0° (s) or different bundling angle (θ) with LB = 3 μm (t). Data are mean ± s.e.m. (a–o). n values refer to independent experiments. Statistical analysis was performed using Wilcoxon’s rank-sum tests (b and c), two-tailed unpaired t-tests (d, e and l–o), Kruskal–Wallis tests with Dunn’s test (i and j) and one-way ANOVA followed by Tukey’s multiple-comparison test (h). For r–t, data are mean ± s.d. (n = 4 each). For b, c and g, scale bars, 100 µm.
