In addition, old SAMP8 mice showed remarkable difference from young controls in terms of the expression level of marker genes, including muscle atrophy genes (fbxo32 and trim63), inflammation and fibrosis- related genes (il1b, tnfa, col1a, and col3a1), and senescence genes (p16 and p21), whose patterns were similar to that in sarcopenia mice 28. This evidence concerns the gene TNF and sarcopenia.