Project description:Muscle atrophy is associated with aging (sarcopenia) and chronic unloading (such as bed confinement and immobilization with casts), as well as various pathological conditions such as type 1 diabetes and nerve injury (denervation). The hindlimb skeletal muscles of C57BL/6 mice (9 weeks old, male) were immobilized (unloaded) by a plaster cast. After 11 days, skeletal muscle was collected and RNA extracted. Expression of Dnmt3a was reduced while expression of Gdf5 was increased by plaster cast immobilization compared to age-matched control mice.
Project description:Skeletal muscle unloading due to joint immobilization induces skeletal muscle atrophy. However, the skeletal muscle proteome response to limb immobilization has not been investigated using SWATH methods. This study quantitatively characterized the muscle proteome at baseline, and after 3 and 14 d of unilateral lower limb (knee-brace) immobilization in 18 healthy young men (25.4 ±5.5 y, 81.2 ±11.6 kg). All muscle biopsies were obtained from the vastus lateralis muscle. Unilateral lower limb immobilization was preceded by four-weeks of exercise training to standardise acute training history, and 7 days of dietary provision to standardise energy/macronutrient intake. Dietary intake was also standardised/provided throughout the 14 d immobilization period.
Project description:Muscle atrophy is associated with aging (sarcopenia) and chronic unloading (such as bed confinement and immobilization with casts), as well as various pathological conditions such as type 1 diabetes and nerve injury (denervation). C57BL/6 mice (7 weeks old, male) were denervated. After 14 days, skeletal muscle was collected and RNA extracted. Expression of Dnmt3a was reduced while expression of Gdf5 was increased by denervation.
Project description:Muscle atrophy is associated with aging (sarcopenia) and chronic unloading (such as bed confinement and immobilization with casts), as well as various pathological conditions such as type 1 diabetes and nerve injury (denervation). Skeletal muscle tissues of young mice (13 weeks old, male) and old mice (25 months old, male) were collected and RNA extracted. Expression of Dnmt3a was reduced while expression of Gdf5 was increased in old mice compared to young mice.
Project description:Human skeletal muscle disuse-atrophy is one of the main problems associated with spaceflight, bed rest, lower limb unloading, or immobilization. This study investigates the effects of 10-day unilateral lower limb suspension (ULLS) followed by 21 days of active recovery (AR) in young healthy men.
Project description:p53 regulates a distinct subset of skeletal muscle mRNAs during immobilization-induced skeletal muscle atrophy For additional details see Fox et al, p53 and ATF4 mediate distinct and additive pathways to skeletal muscle atrophy during limb immobilization. Am J Physiol Endocrinol Metab. 2014 Aug 1;307(3):E245-61. Bilateral tibialis anterior muscles were harvested at three days for the following conditions: 1) hindlimb immobilization of C57BL/6 mice; 2) hindlimb immobilization of p53 mKO and littermate control mice; 3) transfection of wild type mice with p53 plasmid or control plasmid
Project description:Purpose: The goal of this study was to determine the gene expression changes that occur over 7 days in parralyzed muscle in response to isometric contraction elicited by electrical stimulation initiated 4 months after spinal cord injury and to compare such changes to those observed in a normal muscle subjected to overload. Methods: Electrical stimulation of the soleus and plantaris muscle was stimulated in female rats with complete transection of the spinal cord at the interspace between the 9th and 10th thoracic vertebrae. Stimulation was begun 16 weeks after spinal cord transection and produced near-isometric contraction of soleus, plantaris and tibialis anterior. Muscle was analyzed at 1, 2 and 7 days after starting exercise with electrical stimulation. To provide a baseline reference for gene expression at 16 weeks after spinal cord injury, muscle was also analysed from an additional group of spinal cord transected animals. One additional group of animals with a sham-spinal cord injury was included to provide information about gene expression in neurologically intact animals of similar age. In parallel studies, rats underwent bilateral gastrocnemius ablation to overload soleus and plantaris, or a sham ablation as a control. Muscle was analyzed at 1, 3 and 7 days after gastrocnemius ablation or sham-ablation. Gene expression was determined using Affymetrix Rat Exon microarrays. For each group of animals, microarray analysis was performed for soleus muscle for each of 3 separate animals, using one array per animal. Control sammples for the spinal cord injured groups included a group of animals with a Sham-spinal cord injury, and a group of spinal cord injured animals that did not get electrical stimulation. The comparator for determining fold-change expression values was the spinal cord injured group that did not receive electrical stimulation. For each day after gastrocnemius ablation, a control was included that received all procedures needed for this ablation except cutting the distal insertion of the gastrocnemius into the Achilles tendon to control for effects of the surgery on gene expression.
Project description:Following spinal cord injury, skeletal muscle loss is rapid. This severe atrophy is attributed to declines in protein synthesis and increases in protein breakdown. However, the signaling mechanisms controlling these changes are not well understood. Nine male patients and one female patient with spinal cord injury (SCI) (Mean ± SEM = 43.9 ± 6.7 yrs) were recruited for this study. Six patients were quadriplegics and four patients were paraplegics. Inclusion criteria were as follows: patients above the age of 18 yrs, absence of severe brain injury (Glasgow Coma Scale > 13), absence of muscle-crush injury or compartment syndrome, absence of all of the following conditions: hypoxic injury, systemic sepsis, systemic inflammatory or autoimmune disease, and malignancy. Muscle biopsies were obtained from the vastus lateralis muscles of the SCI patients two days and five days post-SCI. Biopsies collected two days post-SCI were included in the current analysis. Expression changes were measured by microarray and gene clustering; identification of enriched functions and canonical pathways were performed using the Database for Annotation, Visualization and Integrated Discovery (DAVID) and Ingenuity Pathway Analysis (IPA). Functional analysis found that 48h following SCI expression, gene expression changes were related to decreases in metabolic functions such as the tricarboxylic acid cycle and oxidative phosphorylation as well as increases in functions associated with protein degradation such as proteasome activity and ubiquitination. Furthermore, increases in expression of metallothioneins were found to be the most over-represented functional group in the DAVID analysis. Results from this study showed that functional categories of gene expression changes in human skeletal muscle are consistent with previous findings in animals. Muscle biopsies were obtained from the vastus lateralis muscles of the SCI patients two days and five days post-SCI. (N = 10). A 5mm Berstrom biopsy needle was used. Biopsy samples were immediately snap-frozen in liquid nitrogen upon excision. All samples were stored at -80° C until analysis.
Project description:Spinal cord injury (SCI) is one of the most disabling health problems facing adults today. Locomotor training has been shown to induce substantial recovery in muscle size and muscle function in both transected and contusion injury animal models of SCI. The overall objective of this study is to implement genome wide expression profiling of skeletal muscle to define the molecular pathways associated with muscle remodeling after SCI and during locomotor training (TM). We profiled rat soleus of total 36 samples including controls; 3, 8 and 14 days after SCI; 8 and 14 days after SCI with locomotor treadmill training (TM).
Project description:Summary: Spinal cord injury (SCI) is a damage to the spinal cord induced by trauma or disease resulting in a loss of mobility or feeling. SCI is characterized by a primary mechanical injury followed by a secondary injury in which several molecular events are altered in the spinal cord often resulting in loss of neuronal function. Analysis of the areas directly (spinal cord) and indirectly (raphe and sensorimotor cortex) affected by injury will help understanding mechanisms of SCI. Hypothesis: Areas of the brain primarily affected by spinal cord injury are the Raphe and the Sensorimotor cortex thus gene expression profiling these two areas might contribute understanding the mechanisms of spinal cord injury. Specific Aim: The project aims at finding significantly altered genes in the Raphe and Sensorimotor cortex following an induced moderate spinal cord injury in T9.