Dark tea extract attenuates age-related muscle loss by suppressing oxidative stress and inflammation in skeletal muscle of mice

[Display omitted] •Dark tea (DT) improved the progressive loss of motor control in aged mice.•DT ameliorated age-related skeletal muscle atrophy in skeletal muscle of mice.•DT suppressed oxidative stress and enhanced antioxidant capacity and mitochondrial function in mice.•DT alleviated inflammation in skeletal muscle of aged mice. Dark tea (DT), a tea post-fermented by the Eurotium cristatum fungus, is known to attenuate oxidative damage and chronic inflammation. It also extends the lifespan of Caenorhabditis elegans fed a high-sugar diet. However, its impact on age-related muscle loss in mice is unclear. We divided 65-week-old male C57BL/6 mice into three groups: old control received the AIN-93 M diet, while the 0.15DT and 0.3DT groups had 0.15 % and 0.3 % DT for 9 weeks. As a result, DT improved grip strength, treadmill performance, muscle weight, and size in aged mice. It reduced cellular senescence, muscle atrophy markers, and angiopoietin-like 2 expression, while increasing sirtuin 1 protein levels in aged mice. Additionally, DT lowered malondialdehyde content and pro-inflammatory cytokine levels and enhanced total antioxidant capacity and enzymes, ultimately attenuating mitochondrial dysfunction in skeletal muscle. Therefore, our results suggest DT attenuates age-related muscle atrophy by alleviating oxidative stress, mitochondrial dysfunction, and inflammation.