Research Paper Volume 13, Issue 1 pp 813—830

Figure 3. L-carnitine promotes oxidative stress recovery during aging and increased lifespan in C.elegans. (A) L-carnitine promoted recovery from oxidative stress during aging. C. elegans expressing the OSR marker gst-4::gfp were synchronized at L1 larvae stage and raised on NG medium supplemented with or without 10 μM L-carnitine. Worms were imaged with fluorescent microscope at L4/young adult (YA) stage, day-2, day-4 day-6 of adulthood. Representative images of 3 independent experiments were shown. (B) Quantification of images from experiment described in (A). Shown were gst-4::gfp levels normalized to the average of L4/young stage. Statistical analysis was performed by two tailed, unpaired student’s t-test (ns, not significant. ***, P<0.001). Error bars indicate standard deviation of the mean. (C) L-carnitine delayed the ROS accumulation in C. elegans during normal aging. Worms were treated as in (A) and stained with DHE dye at indicated time points, followed by imaging with fluorescent microscope. Representative images from 3 experiments were shown. (D) Quantification of DHE-stained ROS levels described in (C). Images from 3 experiments were quantified by ImageJ and statistically analyzed by two-tailed, unpaired student’s t-test (ns, not significant. *, P<0.05). Error bars indicate standard deviation of the mean. (E) L-carnitine prolonged the lifespan of wild-type N2 C. elegans. Wild-type C. elegans were synchronized at L1 larvae stage and raised on NG medium supplemented with or without 10 μM L-carnitine. 50 μM FUDR was added to prevent reproduction. Dead and viable worms were counted every 2 or 3 days starting from day-10 of adulthood. Experiments were performed for 2 times (n>120) and survival were analyzed by log-rank test (Supplementary Table 1). (F) L-carnitine did not extend lifespan of C. elegans with skn-1 knockdown. Experiments were performed similar to (E) except RNAi bacteria was used. Data were pooled from 2 experiments (n>120) and analyzed by log-rank test (Supplementary Table 1). (G) L-carnitine did not extend lifespan of C. elegans with daf-16 knockdown. Experiments were performed similar to (E) except RNAi bacteria was used. Data were pooled from 2 experiments (n>120) and analyzed with log-rank test (Supplementary Table 1).