Transcription profiling of heart tissue from rats that have undergone treadmill exercise or have been sedentary for different lengths of time
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ABSTRACT: Seventy two rats were randomized to twelve independent groups of rats (n = 6 in all groups) where half of the rats were chosen for training (treadmill exercise training 1.5 hour 5 days a week, in 1, 4, 24, 48 days and for 4 and 8 weeks) or sedentary (no training) as described in detail by Wisloff et al. (Intensity-controlled treadmill running in rats: VO(2 max) and cardiac hypertrophy. Am J Physiol Heart Circ Physiol. 2001 Mar;280(3):H1301-10.) or Kemi et al.(Aerobic fitness is associated with cardiomyocyte contractile capacity and endothelial function in exercise training and detraining. Circulation. 2004 Jun 15;109(23):2897-904. Epub 2004 Jun 1.). The rats were scarified one hour after training (1, 4, 24 and 48 days) or 24 hours after training (4 and 8 weeks). Biopsies form left ventricle was taken form all rats and stored on -80°C for preparation of RNA. The same procedures were performed for the control/sedentary rats which were sacrificed at the same time as the exercised rats.
Project description:Endurance exercise training has been shown to decrease whole-body and skeletal muscle insulin resistance and increase glucose tolerance in conditions of both pre-diabetes and overt type 2 diabetes. However, the adaptive responses in skeletal muscle at the molecular and genetic level for these beneficial effects of exercise training have not been clearly established in an animal model of pre-diabetes. The present study identifies alterations in skeletal muscle gene expression that occur with exercise training in pre-diabetic, insulin-resistant obese Zucker (fa/fa) rats and insulin-sensitive lean Zucker (Fa/-) rats. Treadmill running for up to 4 weeks caused significant enhancements of glucose tolerance as assessed by the integrated area under the curve for glucose (AUCg) during an oral glucose tolerance test in both lean and obese animals. Using microarray analysis, a set of only 12 genes was identified as both significantly altered (>1.5-fold change relative to sedentary controls; p<0.05) and significantly correlated (p<0.05) with the AUCg. Two of these genes, peroxisome proliferator-activated receptor-g coactivator 1a (PGC-1a) and the z-isoform of protein kinase C (PKC-z), have known involvement in the regulation of skeletal muscle glucose transport. We confirmed that protein expression levels of PGC-1a and PKC-z were positively correlated with the mRNA expression levels for these two genes. Overall, this study has identified a limited number of genes in soleus muscle of lean and obese Zucker rats that are associated with decreased insulin resistance and increase glucose tolerance following endurance exercise training. These findings could guide the development of pharmaceutical M-^Sexercise mimeticsM-^T in the treatment of insulin-resistant, pre-diabetic or overtly type 2 diabetic individuals.
Project description:Purpose: Aerobic capacity is a strong predictor of cardiovascular mortality. To determine the relationship between inborn aerobic capacity and soleus gene expression we examined genome-wide gene expression in soleus muscle of rats artificially selected for high and low running capacity (HCR and LCR, respectively) over 16 generations. The artificial selection of LCR caused accumulation of risk factors of cardiovascular disease similar to the metabolic syndrome seen in man, whereas HCR had markedly better cardiac function. We also studied alterations in gene expression in response to exercise training in the two groups, since accumulating evidence indicates that exercise has profound beneficial effects on the metabolic syndrome. Methods:; Soleus gene expression of both sedentary and exercise trained HCR and LCR was characterized by microarray- and gene ontology analysis. Results: Although HCR and LCR had an inborn 347% difference in running capacity, only three genes were found differentially expressed in the soleus muscle between the two groups. Up-regulation of the mitochondrial enzyme leucyl-transferRNA synthetase (LARS2) was found in the sedentary LCR. Increased expression of LARS2 has been associated with a mitochondrial DNA mutation linked to maternally inherited diabetes and mitochondrial dysfunction. In line with our findings, a growing body of evidence suggests that LCR have compromised mitochondrial function. After exercise training, 58 genes were altered in the soleus muscle of HCR, in contrast to only one in the LCR group. This suggests that animals born with different levels of fitness respond different to the same type of exercise training. Adaptations to exercise in HCR seemed to be associated with increased lipid metabolism and fatty acid elongation in the mitochondria. Also, genes associated with the peroxisomes, seemed to be central in the adaptation to exercise. Conclusion: The results indicate that (i) LCR might have mitochondrial dysfunction, which may be a contributing factor of the low inborn aerobic capacity, (ii) animals born with different levels of fitness respond different to the same exercise program. Experiment Overall Design: There are 16 samples in this study.
Project description:Consequence of physical exercise in skeletal muscle was investigated in C57BL/6 mice after 4 weeks of exercise training and compared to sedentary controls. Exercised mice received four 4 weeks of regular exercise training on a motorized treadmill and were compared to sedentary controls. 6 mice of each Treatment were used to extract RNA from the quadriceps muscle three hours after the last training bout
Project description:Dahl salt-sensitive (DS) rats were obtained from Harlan Sprague Dawley Laboratory at 5 weeks of age. At 6 weeks of age, physiologic cardiac hypertrophy was generated by a; vigorous daily exercise regimen for 6 weeks (e group). The exercise protocol is based on those described previously with modifications (Wisloff U et al., 2001; Jin H et al., 1994). Rats were exercised daily for 6 weeks on a rodent treadmill (Exer-6M; Columbus Instruments). The exercise program consisted of three weeks of progressively strenuous exercise regimens; followed by three weeks of maintenance period, during which the rats were exercised at 16 m/min at a 5o incline for 90 minutes/day. All rats completed the exercise protocol. Pathological cardiac hypertrophy was generated by feeding a 6% NaCl diet to DS rats at 6 weeks of age (h group) (Inoko M et al., 1994). Control rats (c group) were age matched and sedentary DS rats fed normal rat chow. Read more at http://cardiogenomics.med.harvard.edu/groups/proj1/pages/rat_home.html<br><br>Note that files GSM11886.txt and GSM12308.txt, and files GSM11887.txt and GSM12309.txt as downloaded from GEO contain identical data.
Project description:Here we describe a genome-wide analysis of DNA-methylation in muscle of trained mice. In comparison to sedentary controls 2762 genes exhibited differentially methylated CpGs in their putative promoter regions. The majority of these genes were related to muscle growth and differentiation and a minor fraction involved in metabolic regulation. These findings suggest that DNA-methylation is involved in the regulation of muscle adaptation to regular exercise training. Reduced representation bisulfite sequencing of murine quadriceps muscle
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:Although skeletal muscle metabolism is a well-studied physiological process, little is known about how it is regulated at the transcriptional level. The myogenic transcription factor myogenin is required for skeletal muscle development during embryonic and fetal life, but myogeninâs role in adult skeletal muscle is unclear. We sought to determine myogeninâs function in adult muscle metabolism. A Myog conditional allele and Cre-ER transgene were used to delete Myog in adult mice. Mice were analyzed for exercise capacity by involuntary treadmill running. To assess oxidative and glycolytic metabolism, we monitored blood glucose and lactate levels and performed histochemical analysis on muscle fibers. Surprisingly, we found that Myog-deleted mice performed significantly better than controls in high- and low-intensity treadmill running. This enhanced exercise capacity was due to more efficient oxidative metabolism during low-intensity exercise and more efficient glycolytic metabolism during high-intensity exercise. Furthermore, Myog-deleted mice had an enhanced response to long-term voluntary exercise training on running wheels. We identified several candidate genes whose expression was altered in exercise-stressed muscle of mice lacking myogenin. The results suggest that myogenin plays a critical role as a high-level transcriptional regulator to control the energy balance between aerobic and anaerobic metabolism in adult skeletal muscle. We used microarrays to detail the global program of gene expression underlying enhanced exercise endurance associated with myog-deletion and long-term exercise training. Mouse gastrocnemius muscles were selected after 6 months of myog-deletion and exercise training for RNA extraction and hybridization on Affymetrix microarrays. We chose 3 wild type and 3 myog-deleted mice that best represented the average of each larger group that was tested during our mouse exercise studies.
Project description:Physical exercise training is a known protective factor against cardiovascular morbidity and mortality. Nevertheless, the underlying specific molecular mechanisms still remain uncompletely explored. To identify molecular mechanisms by which exercise training induces this favorable phenotype a genomic approach was used in an animal model of mild exercise previously demonstrated by our group to induce cardioprotection. Our data indicate that mild exercise by inducing no or few permanent changes in gene expression profile is able to determine cardioprotection without induction of cardiac hypertrophy. Experiment Overall Design: We investigated the gene expression profile by Affymetrix technology (230 2.0 GeneChip rat genome array) induced by mild exercise training (treadmill running: 25 m/min, 10% incline, 1 h/day, 3 days/week, 10 weeks) on left ventricle (LV) of exercise-trained (n=10) and sedentary control (n=10) rats.
Project description:The molecular mechanisms of exercise-induced cardiovascular protection are poorly understood. There is growing evidence that reactive oxygen species (ROS) are necessary for some of these adaptations and antioxidants may be used to investigate this effect. This study aimed to determine the effects of exercise and/or antioxidant supplementation on myocardial and vascular endothelium gene expression. Male Wistar rats were divided into four groups: i) endurance exercise (90min of treadmill running 4d/week, 14 weeks); ii) antioxidant-treated; iii) antioxidant and endurance exercise and iv) control. The supplemented animals received Vitamin E (1000 IU/kg diet) and ï¡-lipoic acid (1.6 g/kg diet) mixed with rat chow. cDNA microarray analysis was performed using purified endothelial RNA from myocardial and coronary artery endothelial cells and showed that the expression levels of 35, 40 and 40 genes were altered for groups i, ii, and iii respectively compared to control. Differentially expressed genes were analysed using the KEGG pathway database, hierarchical cluster and DAVID analysis. These analyses revealed that a gene involved in cardiovascular disease progression, Ras homolog gene family member A (RhoA) was down-regulated by exercise, upregulated by antioxidant supplementation and the combination of exercise and antioxidant blunted both effects. These findings were confirmed by real-time PCR. In summary, exercise and antioxidant supplementation affect endothelial cell gene expression and ROS appear necessary for some of these adaptations. 48 Male Wistar rats were divided into four groups: i) endurance exercise (90min of treadmill running 4d/week, 14 weeks); ii) antioxidant-treated; iii) antioxidant and endurance exercise and iv) control. The supplemented animals received Vitamin E (1000 IU/kg diet) and ï¡-lipoic acid (1.6 g/kg diet) mixed with rat chow. cDNA microarray analysis was performed using purified endothelial RNA from myocardial and coronary artery endothelial cells. Based on the limited material available, it was necessary to combine the RNA into three pools per treatment group for CAEC (approx 400 ng of total RNA), and four pools for LVEC (approx 1 μg of total RNA) with an additional reference pool from each control group.
Project description:Quantitative comparison of the protein load of small extracellular vesicles circulating in serum prior and after high intensity interval training.