Research Paper Volume 8, Issue 4 pp 620—635

Figure 4. Influenza infection induced gastrocnemius expression ubiquitin proteasome pathway components that is more dramatic in aged mice. Young and aged C57BL/6 mice were intranasally infected with 500 EID₅₀ of PR8 influenza. At day 0, 3, 7, 11, and 15, mice were fasted for 4-6 hours prior to sacrifice and gastrocnemius muscle was harvested and RNA was isolated. Gene expression was analyzed via RT-qPCR and normalized to reference genes and expression of young mice at day 0 to indicate fold changes. Influenza induced increased skeletal muscle expression of negative muscle regulators (Myostatin (MSTN, C) and Forkhead box protein O1 (FOXO1, D), as well as ubiquitin proteasome components (Atrogin1 (A), MuRF1 (B), Ubiquitin B (UBB, E), and Ubiquitin C (UBC, F). All data was log-transformed and analyzed via two-way ANOVA with Bonferroni post hoc corrections with effect of flu infection over time (compared to day 0, p<0.05) indicated by brackets above data and differences between young and aged mice (p<0.05) at time points indicated by asterisk.