Fig. 3

The inflammatory and mitochondrial comparison between the young and aged DSS-induced colitis mice. a. Body weight changes in young and aged control and DSS-induced colitis mice (N = 5 ~ 8 mice per group). b. The DAI of mice during the indicated period (N = 5 ~ 8 mice per group). Statistical significance was tested with DAI on Day 7. c. qRT-PCR analysis of IL-1β mRNA expression in colon tissues from the 4 groups (N = 5). d. Colonic H&E staining on Day 7 after DSS administration. Loss of crypt architecture and inflammatory cell infiltrations were both detected in colitis groups, and the aged colitis mice presented more severe. Scale bars: 50μm. e. Histological scores of the colon in each group (N = 5 ~ 8 mice per group). f. Transmission electron microscopy images of murine colonic tissues, which manifested swelling mitochondria, broken or disappeared cristae, shallow matrix in colitis group, especially the aged colitis mice. Black arrows indicate the mitochondria. Scale bars: 500nm. g. Mitochondrial number were quantified in each group (N = 3, each point indicate one randomly selected colonocyte). h. ATP levels were measured in colonic tissues of 4 groups (N = 4). Values were expressed as means ± SEM. Statistical significance was determined using one-way ANOVA followed by Tukey’s multiple comparisons test (b, c, e, g) or Kruskal–Wallis test (h). *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001. Abbreviation: qRT-PCR, quantitative real-time polymerase chain reaction; SEM, standard error of the mean; DAI, disease activity index