Fig 1.
Swimming duration change in comparison between the C group, E group, and supplement groups to examine muscular endurance in exercise. Histograms represent mean ± S.E.M. (n = 6–8). aap<0.01, aaap<0.001 versus C group; bbbp<0.001 versus E group; ccp<0.01, cccp<0.001 versus ELP group; dddp<0.001 versus EHP group.
Fig 2.
Muscle force tension analysis at the specified frequency during electrical stimulation of 10 s duration, a 20 s rest period was used. Line graphs represent all frequency and muscle tension (Mean ± S.E.M.) (a). Histograms represent some frequencies; 10 Hz (b), 20 Hz (c), 30 Hz (c) (Mean ± S.E.M., n = 3–7). ap<0.05, aap<0.01 versus C group; bp<0.05 versus E group, ccp<0.01, cccp<0.001 versus ELP group.
Table 1.
Parameters of body weight, muscle weight and biochemical markers for muscle injury and inflammation.
Fig 3.
Muscle glucose uptake and glycogen content.
Fasting serum glucose levels (a), Fasting serum insulin levels (b), Insulin sensitivity (c), Glucose uptake without insulin and with insulin in skeletal muscle (d), Skeletal muscle glycogen content (e), change in comparison between C group, E group, and supplement groups to examine muscle glucose activity. Histograms represent mean ± S.E.M. (n = 6–8). ap<0.05, aap<0.01, aaap<0.001 versus C group; bp<0.05, bbp<0.01, bbbp<0.001 versus E group.
Fig 4.
Protein and gene expression of muscle energy.
Western blot analysis of IRS-1 (a.) and pAKT/AKT (b.) in skeletal muscle. Real-Time PCR SLC2A4 gene (c.) and ATP5B gene in skeletal muscle (d.), change in comparison between the C group, E group and supplement groups to examine insulin signals and ATP synthesis. Histograms represent mean ± S.E.M. (n = 6–8). ap<0.05, aap<0.01, aaap<0.001 versus C group; bp<0.05, bbp<0.01, bbbp<0.001 versus E group.
Table 2.
The parameters of oxidative status and antioxidant enzymes in serum and muscle.
Fig 5.
Antioxidant protein and gene expressions.
Western blotting analysis of Nrf2 in skeletal muscle (a). Real-Time PCR SOD1 gene (b) and GPx1 gene in skeletal muscle (c), change in comparison between C group, E group, and supplement groups to examine antioxidant activity. Histograms represent mean ± S.E.M. (n = 6–8). aap<0.01, aaap<0.001 versus C group; bp<0.05, bbp<0.01, bbbp<0.001 versus E group.
Fig 6.
Gene expressions related to protein synthesis and degradation in muscle.
The relative expression of mTOR (a), Atrogin-1 (b), and MuRF-1 (c) are normalized to GAPDH. RT-PCR technique was used to examine gene expression related to protein synthesis and protein degradation in skeletal muscle. Histograms represent mean ± S.E.M. (n = 6–8). ap<0.05, aap<0.01, aaap<0.001 versus C group; bp<0.05, bbp<0.01, bbbp<0.001 versus E group.
Fig 7.
Histological change by Hematoxylin and eosin stain.
Representative images were taken at a 20x magnification (Scale bar = 100 μm) of cross sections (5 μm) with H&E staining (a), the bold arrow (➡) represents muscle fiber, the arrow (→) represents the nucleus, and the arrowhead (▲) represents perimysium, change in comparison between the C group, E group, and supplement groups to examine muscle fiber size (b), fiber diameter (c) and fiber number (d) in skeletal muscle. Histograms represent mean ± S.E.M. (n = 5). aaap<0.001 versus C group; bbbp<0.001 versus E group.
Fig 8.
Effect of phycocyanin on swimming exercise-induced oxidative stress.
Phycocyanin decreases oxidative damage and reduces inflammation due to excessive exercise, also increases the Nrf2 pathway leading to an enhancement of the antioxidant system, which causes reduced muscle damage. Phycocyanin enhances muscle glucose uptake, insulin sensitivity, GLUT4 expression, and glycogen storage, and improves protein metabolism through the IRS-1/AKT/mTOR signaling pathway. These results show that phycocyanin reduces muscle atrophy and muscle fatigue leading to improved exercise performance.