Research Paper Volume 13, Issue 1 pp 813—830

Carnitine promotes recovery from oxidative stress and extends lifespan in C. elegans

L-carnitine shortens the length of oxidative stress response (OSR) induced by paraquat and juglone. (A) L-carnitine did not affect induction of OSR. 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 to L4/young adult stage. The ROS generator paraquat was then added to the medium to the final concentration of 1 mM. After 24 hours, animals were imaged with a fluorescent microscope. Representative images were shown. (B) Quantification of images taken from at least 3 independent experiments in (A) by ImageJ and relative expression levels were plotted. Statistical analysis was performed by two-tailed, unpaired student’s t-test (ns, not significant. ****, PC) L-carnitine reduced the gst-4::gfp expression during recovery from oxidative stress. C. elegans worms were prepared and treated as in (A). After 24 hours of paraquat treatment, worms were transferred to fresh plate. OSR marker gst-4::gfp were examined at indicated time. (D) Quantification of gst-4::gfp expression in (C). Images from 3 independent experiments were quantified using ImageJ and normalized to the value at time 0. Statistical analysis was performed by two-tailed, unpaired student’s t-test (*, PE) L-carnitine reduced gst-4::gfp expression during recovery from juglone treatment. C. elegans worms were prepared and treated as in (C) except that 300 μM juglone (final concentration) was added to the NG medium. Images from 2 independent experiments were quantified using ImageJ and normalized to the average at 12 hours. Statistical analysis was performed by two-tailed, unpaired student’s t-test (ns, not significant. *, P

Figure 1. L-carnitine shortens the length of oxidative stress response (OSR) induced by paraquat and juglone. (A) L-carnitine did not affect induction of OSR. 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 to L4/young adult stage. The ROS generator paraquat was then added to the medium to the final concentration of 1 mM. After 24 hours, animals were imaged with a fluorescent microscope. Representative images were shown. (B) Quantification of images taken from at least 3 independent experiments in (A) by ImageJ and relative expression levels were plotted. Statistical analysis was performed by two-tailed, unpaired student’s t-test (ns, not significant. ****, P<0.0001). Error bars indicate the standard deviation of the mean. (C) L-carnitine reduced the gst-4::gfp expression during recovery from oxidative stress. C. elegans worms were prepared and treated as in (A). After 24 hours of paraquat treatment, worms were transferred to fresh plate. OSR marker gst-4::gfp were examined at indicated time. (D) Quantification of gst-4::gfp expression in (C). Images from 3 independent experiments were quantified using ImageJ and normalized to the value at time 0. Statistical analysis was performed by two-tailed, unpaired student’s t-test (*, P<0.05. ***, P<0.001). Error bars indicate standard deviation of the mean. (E) L-carnitine reduced gst-4::gfp expression during recovery from juglone treatment. C. elegans worms were prepared and treated as in (C) except that 300 μM juglone (final concentration) was added to the NG medium. Images from 2 independent experiments were quantified using ImageJ and normalized to the average at 12 hours. Statistical analysis was performed by two-tailed, unpaired student’s t-test (ns, not significant. *, P<0.05. **, P<0.001). Error bars indicate standard deviation of the mean.