Prolonged Dietary Curcumin Supplementation Augments Nrf2 Nuclear Translocation and Attenuates Oxidative Stress in Skeletal Muscle of Aging Rats
Authors: Receno Candace N. , Liang Chen , Korol Donna L. , DeRuisseau Keith C. 
Published: June 2021

The development of sarcopenia, which is the aging‐related loss of muscle mass, function and quality, can be attributed to a myriad of factors. Oxidative stress has received particular attention as a key factor in the development of sarcopenia and can collectively be a result of a decreased antioxidant reserve and increased production of reactive oxygen species (ROS). Interestingly, nuclear factor erythroid‐2‐related factor 2 (Nrf2), a transcription factor responsible for activating the antioxidant response element (ARE), has shown decreased nuclear activation with age. Curcumin, the active ingredient in the spice turmeric, has properties that can both increase antioxidant capacity through the activation of Nrf2 and directly quench ROS. These beneficial traits of curcumin were documented in numerous studies that implemented an oral administration method of supplementation. Hence, it is possible that curcumin supplementation through the diet can favorably alter the redox status of muscle and attenuate sarcopenia. This study examined the effects of 4‐months of dietary curcumin exposure on oxidative stress, Nrf2 activation, and the antioxidant response in a rodent model of aging skeletal muscle. Thirty‐two‐month‐old male F344xBN rats (n=54) were provided a purified AIN‐93M diet with or without 0.2% curcumin per food weight for a period of 4 months. One group received the control diet ad libitum (CON, n=18) and another received the same diet containing 0.2% curcumin (CUR, n=18). A third group received the control purified diet, but in equal amounts to those consumed by the CUR animals (PAIR, n=18) to account for any changes in food consumption due to curcumin palatability. After the 4‐month supplementation period, plantaris muscle was tested in vivo for force measures and hindlimb muscle tissue was harvested for biochemical and functional analyses. Body mass, muscle mass, contractile force, measures of oxidative damage, antioxidant expression/activity, and Nrf2 nuclear activation were analyzed using 1‐way ANOVA. All values are reported as mean ± SEM. CUR animals consumed less food than CON rats, and thus a difference between the CON and PAIR groups was also observed (p < 0.05). The CUR rats displayed a significantly larger plantaris mass compared to the PAIR animals (0.198 ± 0.013g vs. 0.326 ± 0.018g; p < 0.05). Plantaris twitch and tetanic force largely mirrored muscle mass changes, where the CUR rats produced larger force than the PAIR rats (p < 0.05). No significant difference in measures of antioxidant expression were observed between the groups (p > 0.05). However, Nrf2 nuclear levels (p < 0.01), and measures of oxidative damage including 3‐nitrotyrosine (3NT; 1.16 ± 0.226 vs. 0.337 ± 0.108 O.D.; p < 0.05), and protein carbonyls (2.29 ± 0.195 vs. 1.43 ± 0.328 O.D.; p < 0.05) were significantly different between the PAIR and CUR groups, respectively. Thus, this study suggests that curcumin supplementation exerts favorable effects on aging muscle that include changes in oxidative stress and muscle mass and function when animals are subjected to food restriction.Support or Funding InformationSupported by the NIH, National Institute on Aging, Grant #1R36AG050734 ‐ 01 (CNR).This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.