Tetraselmis chuii Supplementation Increases Skeletal Muscle Nuclear Factor Erythroid 2-Related Factor 2 and Antioxidant Enzyme Gene Expression, and Peak Oxygen Uptake in Healthy Adults: A Randomised Crossover Trial

Superoxide dismutase-rich Tetraselmis chuii (T. chuii) is derived from marine microalgae and has been reported to increase gene expression of nuclear factor erythroid 2-related factor 2 (NRF2) and related antioxidant enzymes in myoblast tissue culture models. Human research has indicated that T. chuii supplementation can improve recovery from exercise-induced muscle damage, but its effects on endurance exercise performance and the molecular bases that may underlie any ergogenic effects are unclear. Healthy participants underwent 14 days of supplementation with 25 mg·day−1T. chuii and placebo in a randomized, double-blind, crossover experimental design. Prior to and following each supplementation period, participants completed a high-intensity cycling test to assess time to exhaustion and peak oxygen uptake (V˙O2peak). A resting skeletal muscle biopsy was collected after both supplementation periods to assess gene expression changes. Compared to pre-supplementation values, V˙O2peak was increased following T. chuii (p = 0.013) but not placebo (p = 0.66). Fold-change in glutathione peroxidase 7 [(GPX7) 1.26 ± 1.37], glutathione-disulfide reductase [(GSR) 1.22 ± 1.41], glutathione S-transferase Mu 3 [(GSTM3) 1.34 ± 1.49], peroxiredoxin 6 [(PRDX6) 1.36 ± 1.57], extracellular signal-regulated kinase 3 [(ERK3) 1.92 ± 2.42], NRF2 (1.62 ± 2.16), p38 alpha [(p38a) 1.33 ± 1.58] and sirtuin 1 [(SIRT1) 1.73 ± 2.25] gene expression were higher after T. chuii compared to placebo supplementation (p < 0.05). Short-term T. chuii supplementation increased V˙O2peak and skeletal muscle gene expression of key enzymatic antioxidants (GPX7, GSR, GSTM3, and PRDX6), signalling kinases (ERK3 and p38a), post-translational regulators (SIRT1), and transcription factors (NRF2) that may protect against cellular stress insults.