Skeletal muscle mass, strength, and physical performance gains are similar between healthy postmenopausal women and postmenopausal breast cancer survivors after 12 weeks of resistance exercise training.

Purpose: Resistance exercise training (RET) effectively increases skeletal muscle mass and strength in healthy postmenopausal women. However, its effects on these parameters in postmenopausal breast cancer survivors are controversial or limited. Therefore, the aim of this study was to compare the effects of a 12-week progressive whole-body RET program on skeletal muscle mass, strength, and physical performance in healthy postmenopausal women versus postmenopausal women who survived breast cancer.

Changes in Skeletal Muscle Protein Metabolism Signaling Induced by Glutamine Supplementation and Exercise.

Aim: To evaluate the effects of resistance exercise training (RET) and/or glutamine supplementation (GS) on signaling protein synthesis in adult rat skeletal muscles.

Methods: The following groups were studied: (1) control, no exercise (C); (2) exercise, hypertrophy resistance exercise training protocol (T); (3) no exercise, supplemented with glutamine (G); and (4) exercise and supplemented with glutamine (GT). The rats performed hypertrophic training, climbing a vertical ladder with a height of 1.

Autophagy signaling in hypertrophied muscles of diabetic and control rats.

Autophagy plays a vital role in cell homeostasis by eliminating nonfunctional components and promoting cell survival. Here, we examined the levels of autophagy signaling proteins after 7 days of overload hypertrophy in the extensor digitorum longus (EDL) and soleus muscles of control and diabetic rats. We compared control and 3-day streptozotocin-induced diabetic rats, an experimental model for type 1 diabetes mellitus (T1DM).

Molecular and cellular mechanisms involved in tissue-specific metabolic modulation by SARS-CoV-2.

Coronavirus disease 2019 (COVID-19) is triggered by the SARS-CoV-2, which is able to infect and cause dysfunction not only in lungs, but also in multiple organs, including central nervous system, skeletal muscle, kidneys, heart, liver, and intestine. Several metabolic disturbances are associated with cell damage or tissue injury, but the mechanisms involved are not yet fully elucidated. Some potential mechanisms involved in the COVID-19-induced tissue dysfunction are proposed, such as: (a) High expression and levels of proinflammatory cytokines, including TNF-α IL-6, IL-1β, INF-α and INF-β, increasing the systemic and tissue inflammatory state; (b) Induction of oxidative stress due to redox imbalance, resulting in cell injury or death induced by elevated production of reactive oxygen species; and (c) Deregulation of the renin-angiotensin-aldosterone system, exacerbating the inflammatory and oxidative stress responses.

Maternal low-protein diet reduces skeletal muscle protein synthesis and mass Akt-mTOR pathway in adult rats.

Several studies have demonstrated that a maternal low-protein diet induces long-term metabolic disorders, but the involved mechanisms are unclear. This study investigated the molecular effects of a low-protein diet during pregnancy and lactation on glucose and protein metabolism in soleus muscle isolated from adult male rats. Female rats were fed either a normal protein diet or low-protein diet during gestation and lactation.

Endoplasmic Reticulum Stress and Autophagy Markers in Soleus Muscle Disuse-Induced Atrophy of Rats Treated with Fish Oil.

Endoplasmic reticulum stress (ERS) and autophagy pathways are implicated in disuse muscle atrophy. The effects of high eicosapentaenoic (EPA) or high docosahexaenoic (DHA) fish oils on soleus muscle ERS and autophagy markers were investigated in a rat hindlimb suspension (HS) atrophy model. Adult Wistar male rats received daily by gavage supplementation (0.

Addition of Caffeine to a Carbohydrate Feeding Strategy Prior to Intermittent Exercise.

The ergogenic effect of caffeine is well established, although no investigations providing a high carbohydrate feeding strategy (pre-exercise meal=2 g/kg BM) co-ingested with caffeine exist for soccer. This investigation examines the effect of caffeine in addition to a pre-exercise carbohydrate meal and drink mid-way through a soccer simulation. Eight recreational soccer players completed an 85-minute soccer simulation followed by an exercise capacity test (Yo-yo Intermittent Endurance test level 2) on two occasions.

Oral L-glutamine pretreatment attenuates skeletal muscle atrophy induced by 24-h fasting in mice.

L-Glutamine (L-Gln) supplementation has been pointed out as an anticatabolic intervention, but its effects on protein synthesis and degradation signaling in skeketal muscle are still poorly known. The effects of L-Gln pretreatment (1 g kg day body weight for 10 days) on muscle fiber cross-sectional area (CSA), amino acid composition (measured by LC-MS/MS) and protein synthesis (Akt-mTOR) and degradation (ubiquitin ligases) signaling in soleus and extensor digitorum longus (EDL) muscles in 24-h-fasted mice were investigated. The fiber CSA of EDL muscle was not different between the L-Gln-fasted and L-Gln-fed groups.

Experimental Model of HindLimb Suspension-Induced Skeletal Muscle Atrophy in Rodents.

Due to the difficulty of performing research protocols that reproduce human skeletal muscle disuse conditions, an experimental animal model of "hindlimb suspension" (or hindlimb unloading) was developed. This method was created in the 1970s and utilizes rats and mice to mimic space flight and bed rest in humans. It provides an alternative to investigate mechanisms associated with skeletal muscle mass loss and interventions designed to attenuate atrophy induced by hindlimb unloading.

The acute effects of plyometric and sled towing stimuli with and without caffeine ingestion on vertical jump performance in professional soccer players.

Background: Post-activation potentiation (PAP) is the phenomenon by which muscular performance is enhanced in response to a conditioning stimulus. PAP has typically been evidenced via improved counter movement jump (CMJ) performance. This study examined the effects of PAP, with and without prior caffeine ingestion, on CMJ performance.

The role of cathepsin B in autophagy during obesity: A systematic review.

White adipose tissue (WAT) regulates energy homeostasis by releasing adipokines and modulating cell maintenance. Nutrient excess affects adipocyte hypertrophy directly in WAT by increasing excessively the activity of autophagy systems, generating proinflammatory markers and increasing infiltration of macrophages, causing metabolic diseases such as obesity and diabetes. Evidences suggest that cathepsin B (CTSB), a papain-like cysteine peptidase protein, can modulate autophagy processes in adipocytes.

In Vivo Electrical Stimulation for the Assessment of Skeletal Muscle Contractile Function in Murine Models.

Skeletal muscle electrical stimulation is commonly used for clinical purposes, assisting recovery, preservation, or even improvement of muscle mass and function in healthy and pathological conditions. Additionally, it is a useful research tool for evaluation of skeletal muscle contractile function. It may be applied in vitro, using cell culture or isolated fibers/muscles, and in vivo, using human subjects or animal models (neuromuscular electrical stimulation - NMES).

Hypertrophy Stimulation at the Onset of Type I Diabetes Maintains the Soleus but Not the EDL Muscle Mass in Wistar Rats.

Diabetes mellitus induces a reduction in skeletal muscle mass and strength. Strength training is prescribed as part of treatment since it improves glycemic control and promotes increase of skeletal muscle mass. The mechanisms involved in overload-induced muscle hypertrophy elicited at the establishment of the type I diabetic state was investigated in Wistar rats.

Balanced Diet-Fed Fat-1 Transgenic Mice Exhibit Lower Hindlimb Suspension-Induced Soleus Muscle Atrophy.

The consequences of two-week hindlimb suspension (HS) on skeletal muscle atrophy were investigated in balanced diet-fed Fat-1 transgenic and C57BL/6 wild-type mice. Body composition and gastrocnemius fatty acid composition were measured. Skeletal muscle force, cross-sectional area (CSA), and signaling pathways associated with protein synthesis (protein kinase B, Akt; ribosomal protein S6, S6, eukaryotic translation initiation factor 4E-binding protein 1, 4EBP1; glycogen synthase kinase3-beta, GSK3-beta; and extracellular-signal-regulated kinases 1/2, ERK 1/2) and protein degradation (atrophy gene-1/muscle atrophy F-box, atrogin-1/MAFbx and muscle RING finger 1, MuRF1) were evaluated in the soleus muscle.

Iodine excess exposure during pregnancy and lactation impairs maternal thyroid function in rats.

Adequate maternal iodine consumption during pregnancy and lactation guarantees normal thyroid hormones (TH) production, which is crucial to the development of the fetus. Indeed, iodine deficiency is clearly related to maternal hypothyroidism and deleterious effects in the fetal development. Conversely, the effects of iodine excess (IE) consumption on maternal thyroid function are still controversial.

Contractile function recovery in severely injured gastrocnemius muscle of rats treated with either oleic or linoleic acid.

What is the central question of this study? Oleic and linoleic acids modulate fibroblast proliferation and myogenic differentiation in vitro. However, their in vivo effects on muscle regeneration have not yet been examined. We investigated the effects of either oleic or linoleic acid on a well-established model of muscle regeneration after severe laceration.

Oral administration of antioxidants improves skin wound healing in diabetic mice.

Oxidative stress aggravates several long-term complications in diabetes mellitus. We evaluated the effectiveness of the oral administration of antioxidants (vitamins E and C, 40 and 100 mg/kg b.w.

Effects of high EPA and high DHA fish oils on changes in signaling associated with protein metabolism induced by hindlimb suspension in rats.

The effects of either eicosapentaenoic (EPA)- or docosahexaenoic (DHA)-rich fish oils on hindlimb suspension (HS)-induced muscle disuse atrophy were compared. Daily oral supplementations (0.3 mL/100 g b.

Housekeeping proteins: How useful are they in skeletal muscle diabetes studies and muscle hypertrophy models?

The use of Western blot analysis is of great importance in research, and the measurement of housekeeping proteins is commonly used for loading controls. However, Ponceau S staining has been shown to be an alternative to analysis of housekeeping protein levels as loading controls in some conditions. In the current study, housekeeping protein levels were measured in skeletal muscle hypertrophy and streptozotocin-induced diabetes experimental models.

Overload-induced skeletal muscle hypertrophy is not impaired in STZ-diabetic rats.

The aim of this study was to evaluate the effect of overload-induced hypertrophy on extensor digitorum longus (EDL) and soleus muscles of streptozotocin-induced diabetic rats. The overload-induced hypertrophy and absolute tetanic and twitch forces increases in EDL and soleus muscles were not different between diabetic and control rats. Phospho-Akt and rpS6 contents were increased in EDL muscle after 7 days of overload and returned to the pre-overload values after 30 days.

Loss of the anorexic response to systemic 5-aminoimidazole-4-carboxamide-1-β-D-ribofuranoside administration despite reducing hypothalamic AMP-activated protein kinase phosphorylation in insulin-deficient rats.

This study tested whether chronic systemic administration of 5-aminoimidazole-4-carboxamide-1-β-D-ribofuranoside (AICAR) could attenuate hyperphagia, reduce lean and fat mass losses, and improve whole-body energy homeostasis in insulin-deficient rats. Male Wistar rats were first rendered diabetic through streptozotocin (STZ) administration and then intraperitoneally injected with AICAR for 7 consecutive days. Food and water intake, ambulatory activity, and energy expenditure were assessed at the end of the AICAR-treatment period.