Drosophila long-lived O lines are protected from age-related skeletal muscle functional decay. (A) Lifespan extension in the O lines versus B3. B3 flies had a median lifespan of 42 d (n = 180), whereas O1 (n = 273) and O3 (n = 213) flies had a median lifespan of 72 and 76 d, respectively (P < 0.05). (B) With aging, the B3 line displays a progressive increase in the ratio of flies unable to climb, as estimated with negative geotaxis assays (P < 0.05), whereas the O lines are partly protected. (C,D) Analysis of spontaneous locomotion indicates that, although there is no substantial difference in young age (1 wk old) (C), O lines have increased spontaneous locomotion and rhythmicity in old age (6 wk old) (D), compared with the parental B3 strain (P < 0.05; n[batches of 10 flies] = 10). (E,F) Flight defects arise with aging in B3 but less so in the O lines, as also demonstrated by the flight index (F), which is calculated considering all classes of flyers shown in E; n = 100–102, SEM, (***) P < 0.001. (G) Jump ability declines with aging in B3 flies but not in O1 and O3 flies; n = 25, SEM, (***) P < 0.001.
