Figure 5. Proinflammatory cytokines and DNA and protein modifications in relation to age and sex. Serum (A) and liver extracts (B–G) of adult (24 weeks) and old (109-114 weeks) male and female mice (n = 4-5) fed with a chow diet ad libitum were subjected to enzyme-linked immunosorbent assay (A), qRT-PCR analysis (B–D), tandem mass spectrometry (E, F), and immunoblotting (G). This way, proinflammatory cytokines (A–D), global DNA methylation (mdC/dC; E), and hydroxymethylation (hmdC/dC; F), as well as 3-nitrotyrosine (3-NT, G) protein modifications were determined. Hepatic transcription levels (B–D) were normalized by a composite factor based on the house-keeping genes Hprt and Rpl13a, whereas 3-NT-modified proteins were normalized to GAPDH (G). Except for (E) and (F), where data is given in %, data is presented as fold change compared to male adults (A–D, G). Statistical testing based on Two-Way ANOVA and post hoc analysis using Bonferroni’s test with * p < 0.05, ** p < 0.01 vs. adult and # p < 0.05, ### p < 0.001 vs. male.