Aging alters the stiffness of the C. elegans cuticle. (a) Young and aged wild-type worms' immediate response to hyperosmotic shock (0.35 to 1 OSM). Scale bars 100 μm. (b and c) Worms were transferred to 1 OSM solution and imaged after 20 min. Length and area changes of wild-type worms at day 1 and day 10 were calculated; N2/day 1: n = 12, N2/day 10: n = 8. (d and e) Elastic moduli in radial and longitudinal directions for young and aged wild-type worms; N2/day 1: n = 10, N2/day 10: n = 10. (f) Bulk moduli of young and aged wild-type worms. The cuticle softens at small stretching loads and stiffens at larger stretching loads. N2/day 1: n = 10, N2/day 10: n = 10; two biological replicates. Two-tailed t-tests. ∗p < 0.05, ∗∗p < 0.01, ∗∗∗p < 0.001, ∗∗∗∗p < 0.0001. Plots show 25th percentile, median, and 75th percentile. To see this figure in color, go online.