Figure 4. Relative mRNA expression of genes related to lipid metabolism that are differentially expressed during aging and CR (n = 6 per group). (A) Ppara and Ppard are downregulated in aging but upregulated in CR, (B) while the lipogenic genes Acaca and Fasn display opposite trends. (C) Fatty acid oxidation-related genes, such as Cpt2, Cyp4a1, and Acca1a, are downregulated in aging but upregulated in CR. Data are presented as mean ± SEM. *p < 0.05, **p < 0.01, and ***p < 0.001 between two groups.