Normal and fibrotic livers demonstrate strain softening and compression stiffening.

<p>(A-C) G' was measured for normal and fibrotic (after 2 and 6 weeks of CCl₄) livers by shear rheometry under increasing strain and under variable degrees of compression ranging from 0–25%. Note that the y-axes scales are the same and that G' values increase significantly as fibrosis progresses. Curves are mean +/- SD for 3–5 livers tested for each condition. (D) Normal liver subjected to three rounds of shear rheometry, each round with increasing, then decreasing strain. Livers demonstrated no evidence of significant tissue damage due to measurements. Representative liver of 3 tested is shown. (See <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0146588#pone.0146588.s003" target="_blank">S3 Fig</a> for mean curves +/- SD for all three livers tested.)