High-Fat Diet Impairs Muscle Function and Increases the Risk of Environmental Heatstroke in Mice

Proteomic reference map for sarcopenia research: mass spectrometric identification of key muscle proteins located in the sarcomere, cytoskeleton and the extracellular matrix

Sarcopenia of old age is characterized by the progressive loss of skeletal muscle mass and concomitant decrease in contractile strength. Age-related skeletal muscle dysfunctions play a key pathophysiological role in the frailty syndrome and can result in a drastically diminished quality of life in the elderly. Here we have used mass spectrometric analysis of the mouse hindlimb musculature to establish the muscle protein constellation at advanced age of a widely used sarcopenic animal model. Proteomic results were further analyzed by systems bioinformatics of voluntary muscles. In this report, the proteomic survey of aged muscles has focused on the expression patterns of proteins involved in the contraction-relaxation cycle, membrane cytoskeletal maintenance and the formation of the extracellular matrix. This includes proteomic markers of the fast versus slow phenotypes of myosin-containing thick filaments and actin-containing thin filaments, as well as proteins that are associated with the non-sarcomeric cytoskeleton and various matrisomal layers. The bioanalytical usefulness of the newly established reference map was demonstrated by the comparative screening of normal versus dystrophic muscles of old age, and findings were verified by immunoblot analysis.

Selenium improved mitochondrial quality and energy supply in the liver of high-fat diet-fed grass carp (Ctenopharyngodon idella) after heat stress

This study aims to explore the effects of dietary selenium on hepatic mitochondrial quality and energy supply of grass carp (Ctenopharyngodon idella) fed with high-fat diet (HFD) after heat stress (HS). Grass carp were fed with HFD, and HFD contained 0.3 mg/kg nano-selenium for 10 weeks, thereafter exposed to HS from 26 to 34 °C, and named the HFD + HS (control) group and the HFD + Se + HS group, respectively. The results show that selenium significantly prompted the growth, increased glutathione peroxidase (GPX) activity, but reduced malondialdehyde (MDA) content in the liver and the levels of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) in the serum of grass carp fed with HFD after HS. Further, selenium alleviated mitochondrial damage and increased the number of mitochondrial DNA copies in the liver of the grass carp fed with HFD after HS. And selenium also maintained mitochondrial homeostasis by upregulating the expression of mitochondrial quality control-related genes (pgc-1α, nrf1/2, tfam, opa1, mfn1/2, and drp1), mitophagy-related genes (beclin1, atg5, atg12, pink1, and parkin), and the protein expression of parkin and LC3-II/I in the liver of grass carp. Finally, selenium reduced the triglyceride (TG) level and increased the free fatty acid (FFA) level and adenosine triphosphate (ATP) production in the liver of grass carp fed with HFD after HS. In conclusion, dietary selenium alleviated liver damage and improved liver mitochondrial quality and ATP production by increasing liver antioxidant capacity and promoting liver mitochondrial quality in grass carp fed with HFD after HS, which help grass carp to resist these two stressors.

High-refined carbohydrate diet alters different metabolic functions in female rats

A diet containing refined carbohydrate (HCD) caused obesity and white adipose tissue (WAT) abnormalities, but it is unclear if HCD is linked with other metabolic dysfunctions in female models. Thus, we assessed whether HCD results in WAT, pancreas, liver, skeletal muscle (SM) and thyroid (TH) abnormalities in female rats. Female rats were fed with HCD for 15 days and metabolic morphophysiology, inflammation, oxidative stress (OS), and fibrosis markers were assessed. HCD rats presented large adipocytes, hyperleptinemia, and WAT OS. HCD caused irregular glucose metabolism, low insulin levels, and large pancreatic isle. Granulomas, reduced glycogen, and OS were observed in HCD livers. HCD caused hypertrophy and increased in glycogen in SM. HCD caused irregular TH morphophysiology, reduced colloid area and high T3 levels. In all selected tissues, inflammation and fibrosis were observed in HCD rats. Collectively, these data suggest that the HCD impairs metabolic function linked with irregularities in WAT, pancreas, liver, SM and TH in female rats.