Binge drinking leads to an oxidative and metabolic imbalance in skeletal muscle during adolescence in rats: endocrine repercussion

Figures

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  Fig. 1. Skeletal muscle oxidative balance after BD exposure. A Superoxide dismutase (SOD). B Catalase (CAT). C Glutathione peroxidase (GPx) enzymes. D Oxidation of protein (carbonil group (CG) levels). E Lipid peroxidation (malondialdehyde (MDA) levels). The results are expressed as mean ± SEM and analyzed by nonparametric Mann–Whitney–Wilcoxon test. The number of animals in each group is six. Groups: C: control group, BD: binge drinking group. Statistic difference between groups was expressed as p value: C vs BD: *p < 0.05, **p < 0.01

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  Fig. 2. Expression of main energetic regulators in skeletal muscle. A SIRT1. B tAMPK. C pAMPK. D AMPK activation ratio. E Expression lipogenic transcription factor SREBP. F Representative western blots of proteins (normalized to GAPDH). The results are expressed as mean ± SEM and analyzed nonparametric Mann–Whitney–Wilcoxon test. The number of animals in each group is six. Groups: C: control group, BD: binge drinking group. Statistic difference between groups was expressed as p value: **p < 0.01

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  Fig. 3. Expression of main transcription factors implicated in protein metabolism of skeletal muscle: A mTOR. B pmTOR. C FOXO3a. D ULK1. E Atrogin-1/MAFBX. F Representative western blots of proteins (normalized to GAPDH). The results are expressed as mean ± SEM and analyzed by nonparametric Mann–Whitney–Wilcoxon test. The number of animals in each group is six. Groups: C: control group, BD: binge drinking group. Statistic difference between groups was expressed as p value: *p < 0.05

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  Fig. 4. Serum glucose concentration (A) and expression of IRS1 in skeletal muscle (B). C Representative western blots of IRS1 (normalized to GAPDH). The results are expressed as mean ± SEM and analyzed by nonparametric Mann–Whitney–Wilcoxon test. The number of animals in each group is six. Groups: C: control group, BD: binge drinking group. Statistic difference between groups was expressed as p value: *p < 0.05

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  Fig. 5. Effect of BD exposure during adolescence on skeletal muscle metabolism and myokine secretion. When EtOH is consumed in large amounts, as in BD exposure, it arrives at other tissues like SKM. This EtOH generates a great amount of reactive oxygen species, which in the end lead to the appearance of oxidative stress. Consequently, the expression ratio of pAMPK/tAMPK increases, resulting in a stimulated AMPK function. The active AMPK, as an important energy status sensor, regulates several other proteins. On the one hand, it inhibits the expression of SREBP1 and mTOR, which, respectively, will decrease the lipid and protein synthesis; on the other hand, AMPK stimulates FOXO3a and ULK1 expressions. FOXO3a will result in the stimulation of the protein breakdown pathways: it promotes the initiation of autophagy; and increasing the Atrogin-1/MAFBX expression, it also activates the proteosome system. Besides, ULK1, together with FOXO3a, will stimulate the initiation of autophagy and the mitochondrial autophagy process (mitophagy). Additionally, the oxidative stress diminishes the expression of IRS-1, which will not stimulate Akt. This protein, when active, stimulates mTOR and inhibits…