Figure 7

Myriocin protects muscle tissue from tumor-induced atrophy. (A) Mice were inoculated or not with C26 adenocarcinoma, and were injected daily or not with 0.1 mg/kg myriocin. The gastrocnemius and tibialis muscles were dissected and weighed (mean ± SE of 5 to 7 experiments for gastrocnemius; 7 to 10 for tibialis). +++ Different from control: P < 0.0001; *different from 'tumor': P = 0.05. (B) Mean cross-sectional area (CSA) of myofibers was evaluated on transverse sections of gastrocnemius and tibialis muscles (mean ± SE of four experiments for gastrocnemius, seven for tibialis). +++ Different from control: P < 0.0001, ++ P < 0.01; ***different from 'tumor': P = 0.0002, *P = 0.05. (C) Frequency distribution of myofiber CSA in gastrocnemius (mean ± SE of four experiments). 'Tumor' different from 'tumor+myriocin', P < 0.002, + P < 0.01, *P < 0.05. (D) mRNA expression of atrophy-related genes in gastrocnemius was evaluated by reverse transcription quantitative PCR, and normalized to cyclophilin A mRNA. Results are the mean ± SE of four determinations in duplicate. *Different from control, P < 0.05; **P < 0.01; ***P < 0.001; different from 'tumor', P < 0.05. (E) Total ceramide levels were measured in the tibialis of the differently treated mice (mean ± SE, four experiments).