Figure 3. Local deformation and microstructural remodeling of skin sample from K14-COL5A1 mouse (same mouse as Fig. 2).

(a) λ_xx, (b) λ_yy and (c) ω components of the local deformation tensor measured from hair follicle segmentation in the SHG image, x corresponding to the traction direction. Data points correspond to the average over the SHG cropped ROI (~300 × 300 μm²), with error bars calculated as the standard deviation. Solid red lines are linear fitting. The deformation along the traction direction λ_xx varies linearly as a function of the global stretch ratio, with a slope equal to unity, which shows that the global deformation is fully transmitted at the local scale. (d–f) Collagen reorganization probed by SHG imaging; (d) Main orientation angle θ_max of collagen fibers; (e) Orientation index (OI) of the collagen fibers; (f) Statistical entropy (S) of the orientation distribution. Data points correspond to the average over 6 consecutive images (10 μm) with error bars calculated as the standard error of the mean. Solid red lines are linear fitting. The collagen fibers align increasingly along the traction direction (corresponding to angle 0°). Note that λ_yy, entropy and OI exhibit a bimodal behavior with slope switching at the same global stretch value (~1.25).