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Holeček M, Vodeničarovová M, Fingrová R. Dual Effects of Beta-Hydroxy-Beta-Methylbutyrate (HMB) on Amino Acid, Energy, and Protein Metabolism in the Liver and Muscles of Rats with Streptozotocin-Induced Type 1 Diabetes. Biomolecules 2020; 10:biom10111475. [PMID: 33114049 PMCID: PMC7690735 DOI: 10.3390/biom10111475] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 10/20/2020] [Accepted: 10/21/2020] [Indexed: 12/31/2022] Open
Abstract
Beta-hydroxy-beta-methyl butyrate (HMB) is a unique product of leucine catabolism with positive effects on protein balance. We have examined the effects of HMB (200 mg/kg/day via osmotic pump for 7 days) on rats with diabetes induced by streptozotocin (STZ, 100 mg/kg intraperitoneally). STZ induced severe diabetes associated with muscle wasting, decreased ATP in the liver, and increased α-ketoglutarate in muscles. In plasma, liver, and muscles increased branched-chain amino acids (BCAAs; valine, isoleucine, and leucine) and decreased serine. The decreases in mass and protein content of muscles and increases in BCAA concentration were more pronounced in extensor digitorum longus (fast-twitch muscle) than in soleus muscle (slow-twitch muscle). HMB infusion to STZ-treated animals increased glycemia and serine in the liver, decreased BCAAs in plasma and muscles, and decreased ATP in the liver and muscles. The effects of HMB on the weight and protein content of tissues were nonsignificant. We concluded that fast-twitch muscles are more sensitive to STZ than slow-twitch muscles and that HMB administration to STZ-treated rats has dual effects. Adjustments of BCAA concentrations in plasma and muscles and serine in the liver can be considered beneficial, whereas the increased glycemia and decreased ATP concentrations in the liver and muscles are detrimental.
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Dumitru A, Radu BM, Radu M, Cretoiu SM. Muscle Changes During Atrophy. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1088:73-92. [PMID: 30390248 DOI: 10.1007/978-981-13-1435-3_4] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Muscle atrophy typically is a direct effect of protein degradation induced by a diversity of pathophysiologic states such as disuse, immobilization, denervation, aging, sepsis, cachexia, glucocorticoid treatment, hereditary muscular disorders, cancer, diabetes and obesity, kidney and heart failure, and others. Muscle atrophy is defined by changes in the muscles, consisting in shrinkage of myofibers, changes in the types of fiber and myosin isoforms, and a net loss of cytoplasm, organelles and overall a protein loss. Although in the literature there are extensive studies in a range of animal models, the paucity of human data is a reality. This chapter is focused on various aspects of muscle wasting and describes the transitions of myofiber types during the progression of muscle atrophy in several pathological states. Clinical conditions associated with muscle atrophy have been grouped based on the fast-to-slow or slow-to-fast fiber-type shifts. We have also summarized the ultrastructural and histochemical features characteristic for muscle atrophy in clinical and experimental models for aging, cancer, diabetes and obesity, and heart failure and arrhythmia.
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Affiliation(s)
- Adrian Dumitru
- Department of Pathology, Emergency University Hospital, Bucharest, Romania
| | - Beatrice Mihaela Radu
- Faculty of Biology, Department of Anatomy, Animal Physiology and Biophysics, University of Bucharest, Bucharest, Romania.,Life, Environmental and Earth Sciences Division, Research Institute of the University of Bucharest (ICUB), Bucharest, Romania
| | - Mihai Radu
- Department of Life & Environmental Physics, 'Horia Hulubei' National Institute for Physics & Nuclear Engineering, Magurele, Romania
| | - Sanda Maria Cretoiu
- Division of Cell and Molecular Biology and Histology, Carol Davila University of Medicine and Pharmacy, Bucharest, Romania.
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Increased Mitochondrial Protein Levels and Bioenergetics in the Musculus Rectus Femoris of Wfs1-Deficient Mice. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2018; 2018:3175313. [PMID: 30584460 PMCID: PMC6280240 DOI: 10.1155/2018/3175313] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Revised: 08/15/2018] [Accepted: 09/25/2018] [Indexed: 12/19/2022]
Abstract
Wfs1 deficiency leads to a progressive loss of plasma insulin concentration, which should reduce the consumption of glucose in insulin-dependent tissues, causing a variety of changes in intracellular energy metabolism. Our objective here was to assess the changes in the amount and function of mitochondrial proteins in different muscles of Wfs1-deficient mice. Mitochondrial functions were assayed by high-resolution oxygraphy of permeabilized muscle fibers; the protein amount was evaluated by liquid chromatography tandem mass spectrometry (LC/MS/MS) analysis and mRNA levels of the uncoupler proteins UCP2 and UCP3 by real-time PCR; and citrate synthase (CS) activity was determined spectrophotometrically in muscle homogenates. Compared to controls, there were no changes in proton leak and citrate synthase activity in the heart and m. soleus tissues of Wfs1-deficient mice, but significantly higher levels of both of these factors were observed in the m. rectus femoris; mitochondrial proteins and mRNA of UCP2 were also higher in the m. rectus femoris. ADP-stimulated state 3 respiration was lower in the m. soleus, remained unchanged in the heart, and was higher in the m. rectus femoris. The mitochondrial protein amount and activity are higher in Wfs1-deficient mice, as are mitochondrial proton leak and oxygen consumption in m. rectus femoris. These changes in muscle metabolism may be important for identifying the mechanisms responsible for Wolfram syndrome and diabetes.
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Madokoro S, Inaoka PT, Tanaka S, Yamazaki T. Effect of hindlimb unloading and reloading on the soleus and plantaris muscles in diabetic rats. J Phys Ther Sci 2018; 30:1150-1155. [PMID: 30214115 PMCID: PMC6127482 DOI: 10.1589/jpts.30.1150] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2018] [Accepted: 06/22/2018] [Indexed: 11/24/2022] Open
Abstract
[Purpose] This study aimed to induce disuse muscle atrophy in Goto-Kakizaki rats, a type
2 diabetes model, to investigate the effects of reloading on the soleus and plantaris
muscles. [Materials and Methods] Wistar and Goto-Kakizaki (GK) rats were divided into 6
groups: Wistar Control (WC), GK Control (GC), Wistar Tail suspension (WS), GK Tail
suspension (GS), and Wistar Reload (WR), GK Reload (GR). [Results] Investigation of
myofiber cross-sectional area in Goto-Kakizaki rat soleus muscles indicated that the GS
group showed significantly lower values than the GC and GR groups. No significant
differences were observed between the GC and GR groups. However, investigation of
plantaris muscles in Goto-Kakizaki rats indicated that the GS and GR groups showed a
significant decrease compared to the GC group. No significant differences were found
between the GS and GR groups. [Conclusion] Investigation of muscle weight/body weight
ratios and myofiber cross-sectional area in tail suspension groups confirmed the induction
of muscular atrophy. The differences in the degree of atrophy and recovery in terms of
myofiber cross-sectional area observed in Goto-Kakizaki rat plantaris muscles may be
influenced by the myofiber type and diabetes.
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Affiliation(s)
- Sachiko Madokoro
- Division of Health Sciences, Graduate School of Medical Science, Kanazawa University: 5-11-80 Kodatsuno, Kanazawa, lshikawa 920-0942, Japan
| | - Pleiades Tiharu Inaoka
- Division of Health Sciences, Graduate School of Medical Science, Kanazawa University: 5-11-80 Kodatsuno, Kanazawa, lshikawa 920-0942, Japan
| | - Shoji Tanaka
- Division of Health Sciences, Graduate School of Medical Science, Kanazawa University: 5-11-80 Kodatsuno, Kanazawa, lshikawa 920-0942, Japan
| | - Toshiaki Yamazaki
- Division of Health Sciences, Graduate School of Medical Science, Kanazawa University: 5-11-80 Kodatsuno, Kanazawa, lshikawa 920-0942, Japan
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Early energy metabolism-related molecular events in skeletal muscle of diabetic rats: The effects of l-arginine and SOD mimic. Chem Biol Interact 2017; 272:188-196. [PMID: 28483572 DOI: 10.1016/j.cbi.2017.05.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Revised: 04/20/2017] [Accepted: 05/03/2017] [Indexed: 01/17/2023]
Abstract
Considering the vital role of skeletal muscle in control of whole-body metabolism and the severity of long-term diabetic complications, we aimed to reveal the molecular pattern of early diabetes-related skeletal muscle phenotype in terms of energy metabolism, focusing on regulatory mechanisms, and the possibility to improve it using two redox modulators, l-arginine and superoxide dismutase (SOD) mimic. Alloxan-induced diabetic rats (120 mg/kg) were treated with l-arginine or the highly specific SOD mimic, M40403, for 7 days. As appropriate controls, non-diabetic rats received the same treatments. We found that l-arginine and M40403 restored diabetes-induced impairment of phospho-5'-AMP-activated protein kinase α (AMPKα) signaling by upregulating AMPKα protein itself and its downstream effectors, peroxisome proliferator-activated receptor-γ coactivator-1α and nuclear respiratory factor 1. Also, there was a restitution of the protein levels of oxidative phosphorylation components (complex I, complex II and complex IV) and mitofusin 2. Furthermore, l-arginine and M40403 induced translocation of glucose transporter 4 to the membrane and upregulation of protein of phosphofructokinase and acyl coenzyme A dehydrogenase, diminishing negative diabetic effects on limiting factors of glucose and lipid metabolism. Both treatments abolished diabetes-induced downregulation of sarcoplasmic reticulum calcium-ATPase proteins (SERCA 1 and 2). Similar effects of l-arginine and SOD mimic treatments suggest that disturbances in the superoxide/nitric oxide ratio may be responsible for skeletal muscle mitochondrial and metabolic impairment in early diabetes. Our results provide evidence that l-arginine and SOD mimics have potential in preventing and treating metabolic disturbances accompanying this widespread metabolic disease.
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Nguyen T, Obeid J, Walker RG, Krause MP, Hawke TJ, McAssey K, Vandermeulen J, Timmons BW. Fitness and physical activity in youth with type 1 diabetes mellitus in good or poor glycemic control. Pediatr Diabetes 2015; 16:48-57. [PMID: 24444038 DOI: 10.1111/pedi.12117] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/23/2013] [Revised: 10/28/2013] [Accepted: 12/18/2013] [Indexed: 01/05/2023] Open
Abstract
BACKGROUND Patients with type 1 diabetes mellitus (T1DM) may experience poor muscle health as a result of chronic hyperglycemia. Despite this, muscle function in children with T1DM with good or poor glycemic control has yet to be examined in detail. OBJECTIVE To assess differences in muscle-related fitness variables in children with T1DM with good glycemic control (T1DM-G), as well as those with poor glycemic control (T1DM-P), and non-diabetic, healthy controls. SUBJECTS Eight children with T1DM-G [glycosylated hemoglobin (HbA1c) ≤ 7.5% for 9 months], eight children with T1DM-P (HbA1c ≥ 9.0% for 9 months), and eight healthy controls completed one exercise session. METHODS Anaerobic and aerobic muscle functions were assessed with a maximal isometric grip strength test, a Wingate test, and an incremental continuous cycling test until exhaustion. Blood samples were collected at rest to determine HbA1c at the time of testing. Physical activity was monitored over 7 d using accelerometry. RESULTS Children with T1DM-P displayed lower peak oxygen consumption (VO2peak ) values (mL/kg/min) compared to healthy controls (T1DM-P: 33.2 ± 5.6, controls: 43.5 ± 6.3, p < 0.01), while T1DM-G (43.5 ± 6.3) had values similar to controls and T1DM-P. There was a negative relationship between VO2peak and HbA1c% (r = -0.54, p < 0.01). All groups were similar in all other fitness variables. There were no group differences in physical activity variables. CONCLUSION Children with T1DM-G did not display signs of impaired muscle function, while children with T1DM-P have signs of altered aerobic muscle capacity.
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Affiliation(s)
- Thanh Nguyen
- Child Health and Exercise Medicine Program, Department of Pediatrics, McMaster University, Hamilton, ON, L8S 4L8, Canada
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Andreassen CS, Jensen JM, Jakobsen J, Ulhøj BP, Andersen H. Striated muscle fiber size, composition, and capillary density in diabetes in relation to neuropathy and muscle strength. J Diabetes 2014; 6:462-71. [PMID: 24397623 DOI: 10.1111/1753-0407.12124] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2013] [Revised: 12/16/2013] [Accepted: 01/05/2014] [Indexed: 11/29/2022] Open
Abstract
OBJECTIVE Diabetic polyneuropathy (DPN) leads to progressive loss of muscle strength in the lower extremities due to muscular atrophy. Changes in vascularization occur in diabetic striated muscle; however, the relationship between these changes and DPN is as yet unexplored. The aim of the present study was to evaluate histologic properties and capillarization of diabetic skeletal muscle in relation to DPN and muscle strength. METHODS Twenty type 1 and 20 type 2 diabetic (T1D and T2D, respectively) patients underwent biopsy of the gastrocnemic muscle, isokinetic dynamometry at the ankle, electrophysiological studies, clinical examination, and quantitative sensory examinations. Muscle biopsies were stained immunohistochemically and muscle fiber diameter, fiber type distribution, and capillary density determined. Twenty control subjects were also included in the study. RESULTS No relationship was found between muscle fiber diameter, muscle fiber type distribution, or capillary density and degree of neuropathy or muscle strength for either patient group. Muscle fiber diameter and the proportion of Type II fibers were greater for T1D patients than both T2D patients and controls. The T2D patients had fewer capillaries per muscle fiber than T1D patients and controls. CONCLUSIONS Striated muscle fiber size, muscle fiber distribution, and vascularization are unrelated to DPN and muscle strength in diabetes.
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Affiliation(s)
- Christer Swan Andreassen
- Clinical Neurology Research Group, Department of Neurology, Aarhus University Hospital, Aarhus, Denmark; Institute of Clinical Medicine, Aarhus University, Aarhus, Denmark
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In vivo calcium regulation in diabetic skeletal muscle. Cell Calcium 2014; 56:381-9. [PMID: 25224503 DOI: 10.1016/j.ceca.2014.08.008] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2014] [Revised: 07/23/2014] [Accepted: 08/09/2014] [Indexed: 01/30/2023]
Abstract
In skeletal muscle, dysfunctional contractile activity has been linked to impaired intracellular Ca(2+) concentration ([Ca(2+)]i) regulation. Muscle force production is impaired and fatigability and muscle fragility deteriorate with diabetes. Use of a novel in vivo model permits investigation of [Ca(2+)]i homeostasis in diabetic skeletal muscle. Within this in vivo environment we have shown that diabetes perturbs the Ca(2+) regulatory system such that resting [Ca(2+)]i homeostasis following muscle contractions is compromised and elevations of [Ca(2+)]i are exacerbated. This review considers the impact of diabetes on the capacity of skeletal muscle to regulate [Ca(2+)]i, following muscle contractions and, in particular, the relationship between muscle fatigue and elevated [Ca(2+)]i in a highly ecologically relevant circulation-intact environment. Importantly, the role of mitochondria in calcium sequestration and the possibility that diabetes impacts this process is explored. Given the profound microcirculatory dysfunction in diabetes this preparation offers the unique opportunity to study the interrelationships among microvascular function, blood-myocyte oxygen flux and [Ca(2+)]i as they relate to enhanced muscle fatigability and exercise intolerance.
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KATAOKA H, NAKANO J, MORIMOTO Y, HONDA Y, SAKAMOTO J, ORIGUCHI T, OKITA M, YOSHIMURA T. Hyperglycemia Inhibits Recovery From Disuse-Induced Skeletal Muscle Atrophy in Rats. Physiol Res 2014; 63:465-74. [DOI: 10.33549/physiolres.932687] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
The purpose of this study was to evaluate the effects of hyperglycemia on skeletal muscle recovery following disuse-induced muscle atrophy in rats. Wistar rats were grouped as streptozotocin-induced diabetic rats and non-diabetic rats. Both ankle joints of each rat were immobilized to induce atrophy of the gastrocnemius muscles. After two weeks of immobilization and an additional two weeks of recovery, tail blood and gastrocnemius muscles were isolated. Serial cross sections of muscles were stained for myosin ATPase (pH 4.5) and alkaline phosphatase activity. Serum insulin and muscle insulin-like growth factor-1 (IGF-1) levels were also measured. Serum insulin levels were significantly reduced in the diabetic rats compared to the non-diabetic controls. The diameters of type I, IIa, and IIb myofibers and capillary-to-myofiber ratio in the isolated muscle tissue were decreased after immobilization in both treatments. During the recovery period, these parameters were restored in the non-diabetic rats, but not in the diabetic rats. In addition, muscle IGF-1 levels after recovery increased significantly in the non-diabetic rats, but not in the diabetic rats. We conclude that decreased levels of insulin and IGF-1 and impairment of angiogenesis associated with diabetes might be partly responsible for the inhibition of regrowth in diabetic muscle.
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Affiliation(s)
| | - J. NAKANO
- Unit of Physical Therapy and Occupational Therapy Sciences, Nagasaki University Graduate School of Biomedical Sciences, Japan
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Krause MP, Al-Sajee D, D’Souza DM, Rebalka IA, Moradi J, Riddell MC, Hawke TJ. Impaired macrophage and satellite cell infiltration occurs in a muscle-specific fashion following injury in diabetic skeletal muscle. PLoS One 2013; 8:e70971. [PMID: 23951058 PMCID: PMC3741394 DOI: 10.1371/journal.pone.0070971] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2013] [Accepted: 06/26/2013] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND Systemic elevations in PAI-1 suppress the fibrinolytic pathway leading to poor collagen remodelling and delayed regeneration of tibialis anterior (TA) muscles in type-1 diabetic Akita mice. However, how impaired collagen remodelling was specifically attenuating regeneration in Akita mice remained unknown. Furthermore, given intrinsic differences between muscle groups, it was unclear if the reparative responses between muscle groups were different. PRINCIPAL FINDINGS Here we reveal that diabetic Akita muscles display differential regenerative responses with the TA and gastrocnemius muscles exhibiting reduced regenerating myofiber area compared to wild-type mice, while soleus muscles displayed no difference between animal groups following injury. Collagen levels in TA and gastrocnemius, but not soleus, were significantly increased post-injury versus controls. At 5 days post-injury, when degenerating/necrotic regions were present in both animal groups, Akita TA and gastrocnemius muscles displayed reduced macrophage and satellite cell infiltration and poor myofiber formation. By 10 days post-injury, necrotic regions were absent in wild-type TA but persisted in Akita TA. In contrast, Akita soleus exhibited no impairment in any of these measures compared to wild-type soleus. In an effort to define how impaired collagen turnover was attenuating regeneration in Akita TA, a PAI-1 inhibitor (PAI-039) was orally administered to Akita mice following cardiotoxin injury. PAI-039 administration promoted macrophage and satellite cell infiltration into necrotic areas of the TA and gastrocnemius. Importantly, soleus muscles exhibit the highest inducible expression of MMP-9 following injury, providing a mechanism for normative collagen degradation and injury recovery in this muscle despite systemically elevated PAI-1. CONCLUSIONS Our findings suggest the mechanism underlying how impaired collagen remodelling in type-1 diabetes results in delayed regeneration is an impairment in macrophage infiltration and satellite cell recruitment to degenerating areas; a phenomena that occurs differentially between muscle groups.
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Affiliation(s)
- Matthew P. Krause
- Department of Pathology & Molecular Medicine, McMaster University, Hamilton, Ontario, Canada
| | - Dhuha Al-Sajee
- Department of Pathology & Molecular Medicine, McMaster University, Hamilton, Ontario, Canada
| | - Donna M. D’Souza
- Department of Pathology & Molecular Medicine, McMaster University, Hamilton, Ontario, Canada
| | - Irena A. Rebalka
- Department of Pathology & Molecular Medicine, McMaster University, Hamilton, Ontario, Canada
| | - Jasmin Moradi
- Department of Pathology & Molecular Medicine, McMaster University, Hamilton, Ontario, Canada
| | - Michael C. Riddell
- Muscle Health Research Centre, York University, Toronto, Ontario, Canada
| | - Thomas J. Hawke
- Department of Pathology & Molecular Medicine, McMaster University, Hamilton, Ontario, Canada
- Muscle Health Research Centre, York University, Toronto, Ontario, Canada
- * E-mail:
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Serino AS, Adegoke OA, Zargar S, Gordon CS, Szigiato AA, Hawke TJ, Riddell MC. Voluntary physical activity and leucine correct impairments in muscle protein synthesis in partially pancreatectomised rats. Diabetologia 2011; 54:3111-20. [PMID: 21909838 DOI: 10.1007/s00125-011-2296-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2011] [Accepted: 08/02/2011] [Indexed: 11/26/2022]
Abstract
AIMS/HYPOTHESIS Poorly controlled type 1 diabetes mellitus can cause reduced skeletal muscle mass and weakness during adolescence, which may affect long-term management of the disease. The aim of this study was to determine whether regular voluntary physical activity and leucine feeding restore rates of protein synthesis and deficits in skeletal muscle mass in a young, hypoinsulinaemic/hyperglycaemic rat model of diabetes. METHODS Four-week-old male Sprague-Dawley rats were partially pancreatectomised (Px) to induce hypoinsulinaemia/hyperglycaemia and housed with/without access to running wheels for 3 weeks (n = 12-14/group). Sham surgery rats (shams) served as sedentary controls (n = 18). Protein synthesis and markers of protein anabolism were assessed in the fasted state and following leucine gavage. Fibre type and cross-sectional areas of the gastrocnemius muscle were measured using a metachromatic ATPase stain. RESULTS Compared with sedentary behaviour, regular activity lowered fasting glycaemia and reduced fed hyperglycaemia in Px rats. Active-Px rats, which ran 2.2 ± 0.71 km/night, displayed greater muscle mass and fibre areas similar to shams, while sedentary-Px rats displayed a 20-30% loss in muscle fibre areas. Muscle protein synthesis (basal and in response to leucine gavage) was impaired in sedentary-Px (by ~65%), but not in active-Px rats, when compared with shams. Following leucine gavage, the phosphorylation status of eIF4E binding protein 1 (4E-BP1) and ribosomal S6 kinase 1 (S6K1), markers of mammalian target of rapamycin complex 1 (mTORC1) signalling, increased in shams (by two- and ninefold, respectively) and in active-Px (1.5- and fourfold, respectively) rats, but not in sedentary-Px rats. CONCLUSION/INTERPRETATION Moderate physical activity in young Px rats normalises impairments in skeletal muscle growth and protein synthesis. These findings illustrate the critical compensatory role that modest physical activity and targeted nutrition can have on skeletal muscle growth during periods of hypoinsulinaemia in adolescent diabetes.
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Affiliation(s)
- A S Serino
- School of Kinesiology and Health Science, York University, 4700 Keele Street, Toronto, ON, Canada
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Krause MP, Riddell MC, Hawke TJ. Effects of type 1 diabetes mellitus on skeletal muscle: clinical observations and physiological mechanisms. Pediatr Diabetes 2011; 12:345-64. [PMID: 20860561 DOI: 10.1111/j.1399-5448.2010.00699.x] [Citation(s) in RCA: 102] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Affiliation(s)
- Matthew P Krause
- Dept of Pathology & Molecular Medicine, McMaster University, 1200 Main St., W. Hamilton, ON, Canada L8N 3Z5
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Strunz CMC, Matsuda M, Salemi VMC, Nogueira A, Mansur AP, Cestari IN, Marquezini MV. Changes in cardiac heparan sulfate proteoglycan expression and streptozotocin-induced diastolic dysfunction in rats. Cardiovasc Diabetol 2011; 10:35. [PMID: 21518435 PMCID: PMC3100243 DOI: 10.1186/1475-2840-10-35] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/22/2011] [Accepted: 04/25/2011] [Indexed: 02/02/2023] Open
Abstract
Background Changes in the proteoglycans glypican and syndecan-4 have been reported in several pathological conditions, but little is known about their expression in the heart during diabetes. The aim of this study was to investigate in vivo heart function changes and alterations in mRNA expression and protein levels of glypican-1 and syndecan-4 in cardiac and skeletal muscles during streptozotocin (STZ)-induced diabetes. Methods Diabetes was induced in male Wistar rats by STZ administration. The rats were assigned to one of the following groups: control (sham injection), after 24 hours, 10 days, or 30 days of STZ administration. Echocardiography was performed in the control and STZ 10-day groups. Western and Northern blots were used to quantify protein and mRNA levels in all groups. Immunohistochemistry was performed in the control and 30-day groups to correlate the observed mRNA changes to the protein expression. Results In vivo cardiac functional analysis performed using echocardiography in the 10-day group showed diastolic dysfunction with alterations in the peak velocity of early (E) diastolic filling and isovolumic relaxation time (IVRT) indices. These functional alterations observed in the STZ 10-day group correlated with the concomitant increase in syndecan-4 and glypican-1 protein expression. Cardiac glypican-1 mRNA and skeletal syndecan-4 mRNA and protein levels increased in the STZ 30-day group. On the other hand, the amount of glypican in skeletal muscle was lower than that in the control group. The same results were obtained from immunohistochemistry analysis. Conclusion Our data suggest that membrane proteoglycans participate in the sequence of events triggered by diabetes and inflicted on cardiac and skeletal muscles.
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Affiliation(s)
- Célia M C Strunz
- Heart Institute, University of São Paulo Medical School, São Paulo 05403-000, Brazil.
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Li P, Waters RE, Redfern SI, Zhang M, Mao L, Annex BH, Yan Z. Oxidative phenotype protects myofibers from pathological insults induced by chronic heart failure in mice. THE AMERICAN JOURNAL OF PATHOLOGY 2007; 170:599-608. [PMID: 17255328 PMCID: PMC1851852 DOI: 10.2353/ajpath.2007.060505] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The fiber specificity of skeletal muscle abnormalities in chronic heart failure (CHF) has not been defined. We show here that transgenic mice (8 weeks old) with cardiac-specific overexpression of calsequestrin developed CHF (50.9% decrease in fractional shortening and 56.4% increase in lung weight, P<0.001), cachexia (37.8% decrease in body weight, P<0.001), and exercise intolerance (69.3% decrease in running distance to exhaustion, P<0.001) without a significant change in muscle fiber-type composition. Slow oxidative soleus muscle maintained muscle mass, whereas fast glycolytic tibialis anterior and plantaris muscles underwent atrophy (11.6 and 13.3%, respectively; P<0.05). In plantaris muscle, glycolytic type IId/x and IIb, but not oxidative type I and IIa, fibers displayed significant decreases in cross-sectional area (20.3%, P<0.05). Fast glycolytic white vastus lateralis muscle showed sarcomere degeneration and decreased cytochrome c oxidase IV (39.5%, P<0.01) and peroxisome proliferator-activated receptor gamma co-activator 1alpha protein expression (30.3%, P<0.01) along with a dramatic induction of the MAFbx/Atrogin-1 mRNA. These findings suggest that exercise intolerance can occur in CHF without fiber type switching in skeletal muscle and that oxidative phenotype renders myofibers resistant to pathological insults induced by CHF.
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Affiliation(s)
- Ping Li
- Division of Cardiology, Department of Medicine, Duke University Medical Center, 4321 Medical Park Dr., Suite 200, Durham, NC 27704, USA
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Snow LM, Lynner CB, Nielsen EM, Neu HS, Thompson LV. Advanced Glycation End Product in Diabetic Rat Skeletal Muscle in vivo. Pathobiology 2007; 73:244-51. [PMID: 17314495 DOI: 10.1159/000098210] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2006] [Accepted: 10/12/2006] [Indexed: 01/25/2023] Open
Abstract
BACKGROUND Advanced glycation end products (AGEs) are implicated in the etiology of diabetic complications in the kidney, nerve and eye. Skeletal muscle contractile parameters have also been found to be altered in diabetes. Glycation has not been extensively studied in skeletal muscle, but AGE-modified proteins may influence contractility. OBJECTIVE AND METHODS The aim of this study was to use immunohistochemistry to identify distribution patterns of the AGE Nepsilon-(carboxymethyl)-lysine in plantaris muscle of diabetic rats. RESULTS Results revealed the presence of Nepsilon-(carboxymethyl)-lysine intracellularly and also at sites along the myofiber periphery. The number of myofibers immunolabeling for AGE in animals with diabetes was more than 4-fold greater than in control animals. Additionally, there was a greater proportion of slow + fast myosin heavy chain coexpression in the AGE-positive cells from diabetic animals than in AGE-positive fibers from control animals. No significant difference was present between cross-sectional areas of AGE-positive fibers and AGE-negative fibers within the respective experimental groups. CONCLUSIONS AGE accumulation is greater in skeletal muscle in vivo from diabetic animals than in control animals. This AGE accumulation appears to be associated with fiber-type transformation rather than with myofiber size. Further study is needed to determine the identity of these AGE-modified proteins and to determine how they influence skeletal muscle function in diabetes.
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Affiliation(s)
- LeAnn M Snow
- Department of Physical Medicine and Rehabilitation, University of Minnesota, Minneapolis, MN 55455, USA.
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16
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Lehti TM, Silvennoinen M, Kivelä R, Kainulainen H, Komulainen J. Effects of streptozotocin-induced diabetes and physical training on gene expression of titin-based stretch-sensing complexes in mouse striated muscle. Am J Physiol Endocrinol Metab 2007; 292:E533-42. [PMID: 17003243 DOI: 10.1152/ajpendo.00229.2006] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In striated muscle, a sarcomeric noncontractile protein, titin, is proposed to form the backbone of the stress- and strain-sensing structures. We investigated the effects of diabetes, physical training, and their combination on the gene expression of proteins of putative titin stretch-sensing complexes in skeletal and cardiac muscle. Mice were divided into control (C), training (T), streptozotocin-induced diabetic (D), and diabetic training (DT) groups. Training groups performed for 1, 3, or 5 wk of endurance training on a motor-driven treadmill. Muscle samples from T and DT groups together with respective controls were collected 24 h after the last training session. Gene expression of calf muscles (soleus, gastrocnemius, and plantaris) and cardiac muscle were analyzed using microarray and quantitative PCR. Diabetes induced changes in mRNA expression of the proteins of titin stretch-sensing complexes in Z-disc (MLP, myostatin), I-band (CARP, Ankrd2), and M-line (titin kinase signaling). Training alleviated diabetes-induced changes in most affected mRNA levels in skeletal muscle but only one change in cardiac muscle. In conclusion, we showed diabetes-induced changes in mRNA levels of several fiber-type-biased proteins (MLP, myostatin, Ankrd2) in skeletal muscle. These results are consistent with previous observations of diabetes-induced atrophy leading to slower fiber type composition. The ability of exercise to alleviate diabetes-induced changes may indicate slower transition of fiber type.
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Affiliation(s)
- T Maarit Lehti
- LIKES Research Center for Sport and Health Sciences, Rautpohjankatu 8, Viveca, FIN-40700 Jyväskylä, Finland.
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17
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Park SW, Goodpaster BH, Strotmeyer ES, de Rekeneire N, Harris TB, Schwartz AV, Tylavsky FA, Newman AB. Decreased muscle strength and quality in older adults with type 2 diabetes: the health, aging, and body composition study. Diabetes 2006; 55:1813-8. [PMID: 16731847 DOI: 10.2337/db05-1183] [Citation(s) in RCA: 511] [Impact Index Per Article: 28.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Adequate skeletal muscle strength is essential for physical functioning and low muscle strength is a predictor of physical limitations. Older adults with diabetes have a two- to threefold increased risk of physical disability. However, muscle strength has never been investigated with regard to diabetes in a population-based study. We evaluated grip and knee extensor strength and muscle mass in 485 older adults with diabetes and 2,133 without diabetes in the Health, Aging, and Body Composition study. Older adults with diabetes had greater arm and leg muscle mass than those without diabetes because they were bigger in body size. Despite this, muscle strength was lower in men with diabetes and not higher in women with diabetes than corresponding counterparts. Muscle quality, defined as muscle strength per unit regional muscle mass, was significantly lower in men and women with diabetes than those without diabetes in both upper and lower extremities. Furthermore, longer duration of diabetes (>or=6 years) and poor glycemic control (HbA(1c) >8.0%) were associated with even poorer muscle quality. In conclusion, diabetes is associated with lower skeletal muscle strength and quality. These characteristics may contribute to the development of physical disability in older adults with diabetes.
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Affiliation(s)
- Seok Won Park
- Department of Internal Medicine, Pochon CHA University, Pochon, Korea.
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18
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Snow LM, Sanchez OA, McLoon LK, Serfass RC, Thompson LV. Effect of endurance exercise on myosin heavy chain isoform expression in diabetic rats with peripheral neuropathy. Am J Phys Med Rehabil 2005; 84:770-9. [PMID: 16205433 DOI: 10.1097/01.phm.0000176350.61935.d6] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE This study evaluated the effect of endurance exercise on myosin heavy chain (MHC) isoform expression in soleus muscle of diabetic rats with peripheral neuropathy. DESIGN Male Sprague Dawley rats were randomly divided into four groups: control sedentary, diabetic sedentary, control exercise, and diabetic exercise. The exercised animals performed treadmill running five times per week. After 12 wks, electrophysiologic testing documented peripheral neuropathy in the diabetic rats. The soleus muscles were then excised and quick-frozen. Cross-sections were immunohistochemically stained for slow, fast, developmental, and neonatal MHCs. Fiber-type composition and fiber cross-sectional areas were then determined. RESULTS The diabetic groups showed a significantly greater percentage of fast MHC than did the control groups, regardless of exercise status (diabetic sedentary, 22.6%; diabetic exercise, 25.2%; control sedentary, 13.5%; control exercise, 13.1%). The diabetics also showed a significantly lower percentage of slow-only MHC than controls (diabetic sedentary, 77.1%; diabetic exercise, 74.3%; control sedentary, 86.2%; control exercise, 86.1%). No differences in muscle fiber cross-sectional area existed between the groups. The exercised animals showed greater expression of developmental MHC than did the sedentary animals (diabetic sedentary, 1.6%; diabetic exercise, 3.8%; control sedentary, 0.8%; control exercise, 2.0%). CONCLUSION The altered slow and fast MHC expression in the diabetic muscle is similar to MHC expression in several other conditions, including decreased neuromuscular activity and denervation. Mechanisms of this MHC expression shift are unknown. Chronic endurance training does not alter adult MHC expression in the diabetic animals. The developmental MHC expression is likely a manifestation of uphill treadmill running due to eccentric contractions in the soleus resulting in myofiber injury and regeneration.
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Affiliation(s)
- Leann M Snow
- Department of Physical Medicine and Rehabilitation, University of Minnesota Medical School, Minneapolis, Minnesota 55455, USA
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19
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Snow LM, Sanchez OA, McLoon LK, Serfass RC, Thompson LV. Myosin heavy chain isoform immunolabelling in diabetic rats with peripheral neuropathy. Acta Histochem 2005; 107:221-9. [PMID: 16054675 DOI: 10.1016/j.acthis.2005.06.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2005] [Revised: 05/25/2005] [Accepted: 06/06/2005] [Indexed: 11/29/2022]
Abstract
This study evaluated mature and immature myosin heavy chain (MHC) isoform immunolocalisation in soleus muscle of diabetic rats with documented motor neuropathy. Sprague Dawley rats were assigned to one of three groups: control (C), diabetic with insulin (DI), or diabetic without insulin (DNI). Twelve weeks after diabetes induction, soleus muscles were excised and quick-frozen. Cross-sections were labelled immunohistochemically for slow, fast, developmental and neonatal MHC isoforms to determine fiber-type composition. Fiber cross-sectional areas were determined morphometrically. Results revealed that DNI and DI muscles contained greater percentages of myofibers positive for fast MHC compared with controls. DNI animals also showed a lower percentage of myofibers positive for slow MHC compared to the DI group. The number of fibers immunolabelled for developmental MHC isoforms was greater in DNI animals than in the other groups. The differences in slow and fast MHC-labelling appear to indicate a condition of altered neuromuscular activity affecting the diabetic muscles. The increase in developmental MHC-labelling in the DNI muscles could indicate myofiber regeneration or reinnervation that would be more pronounced in the DNI animals in context of their more severe neuropathy. Insulin appeared to influence muscle fiber cross-sectional area and possibly fiber-type grouping frequency; the potential mechanism for these effects was not elucidated.
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MESH Headings
- Animals
- Diabetes Mellitus, Experimental/metabolism
- Diabetes Mellitus, Experimental/pathology
- Diabetic Neuropathies/metabolism
- Diabetic Neuropathies/pathology
- Disease Models, Animal
- Image Processing, Computer-Assisted
- Immunohistochemistry
- Male
- Muscle Fibers, Fast-Twitch/metabolism
- Muscle Fibers, Fast-Twitch/pathology
- Muscle Fibers, Slow-Twitch/metabolism
- Muscle Fibers, Slow-Twitch/pathology
- Muscle, Skeletal/metabolism
- Muscle, Skeletal/pathology
- Myosin Heavy Chains/metabolism
- Protein Isoforms
- Rats
- Rats, Sprague-Dawley
- Staining and Labeling
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Affiliation(s)
- LeAnn M Snow
- Department of Physical Medicine and Rehabilitation, University of Minnesota Medical School, MMC 388, 420 Delaware Street SE, Minneapolis, MN 55455, USA
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20
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Sanchez OA, Snow LM, Lowe DA, Serfass RC, Thompson LV. Effects of endurance exercise-training on single-fiber contractile properties of insulin-treated streptozotocin-induced diabetic rats. J Appl Physiol (1985) 2005; 99:472-8. [PMID: 15831797 DOI: 10.1152/japplphysiol.01233.2004] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The purpose of this study was to characterize the contractile properties of individual skinned muscle fibers from insulin-treated streptozotocin-induced diabetic rats after an endurance exercise training program. We hypothesized that single-fiber contractile function would decrease in the diabetic sedentary rats and that endurance exercise would preserve the function. In the study, 28 rats were assigned to either a nondiabetic sedentary, a nondiabetic exercise, a diabetic sedentary, or a diabetic exercise group. Rats in the diabetic groups received subcutaneous intermediate-lasting insulin daily. The exercise-trained rats ran on a treadmill at a moderate intensity for 60 min, five times per week. After 12 wk, the extensor digitorum longus and soleus muscles were dissected. Single-fiber diameter, Ca2+-activated peak force, specific tension, activation threshold, and pCa50as well as the myosin heavy chain isoform expression (MHC) were determined. We found that in MHC type II fibers from extensor digitorum longus muscle, diameters were significantly smaller from diabetic sedentary rats compared with nondiabetic sedentary rats ( P < 0.001). Among the nondiabetic rats, fiber diameters were smaller with exercise ( P = 0.038). The absolute force-generating capacity of single fibers was lower in muscles from diabetic rats. There was greater specific tension (force normalized to cross-sectional area) by fibers from the rats that followed an endurance exercise program compared with sedentary. From the results, we conclude that alterations in the properties of contractile proteins are not implicated in the decrease in strength associated with diabetes and that endurance-exercise training does not prevent or increase muscle weakness in diabetic rats.
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MESH Headings
- Adaptation, Physiological/physiology
- Animals
- Cells, Cultured
- Diabetes Mellitus, Experimental/chemically induced
- Diabetes Mellitus, Experimental/drug therapy
- Diabetes Mellitus, Experimental/physiopathology
- Insulin/therapeutic use
- Isometric Contraction
- Muscle Fibers, Skeletal
- Muscle, Skeletal/physiopathology
- Physical Conditioning, Animal/methods
- Physical Endurance
- Rats
- Rats, Sprague-Dawley
- Streptozocin
- Stress, Mechanical
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Affiliation(s)
- Otto A Sanchez
- School of Kinesiology, University of Minnesota Medical School, 420 Delaware Street, Minneapolis, MN 55455, USA
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21
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Lesniewski LA, Miller TA, Armstrong RB. Mechanisms of force loss in diabetic mouse skeletal muscle. Muscle Nerve 2003; 28:493-500. [PMID: 14506722 DOI: 10.1002/mus.10468] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Pathologic changes to alpha-motoneurons may contribute to decreases in skeletal muscle strength in diabetes. The present study examines this possibility. Female ICR mice (approximately 25 g) were given a single injection of streptozotocin (200 mg/kg). After 2, 4, and 8 weeks of diabetes, we measured maximum isometric tetanic torque of the fast-twitch anterior crural muscles at the ankle when stimulated through the common peroneal nerve, and maximal isometric tetanic force in the directly stimulated extensor digitorum longus (EDL) muscle. After 4 weeks, the relative loss of torque via nerve stimulation (-43%) was greater (P = 0.02) than the force loss in the directly stimulated muscle (-24%), indicating a functional neural deficit. However, the percent changes in strength in these two methods of stimulation were not different (P = 0.41) in the 8-week diabetic animals, indicating that functional impairment resided in the muscle. This suggests an early distal motoneuron or neuromuscular junction deficit that improved as the intrinsic muscle deficit worsened. Preliminary evidence also suggests excitation-contraction uncoupling may contribute to the loss of strength in fast-twitch muscles.
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Affiliation(s)
- Lisa A Lesniewski
- Muscle Biology Laboratory, Department of Health and Kinesiology, Texas A&M University, College Station, Texas 77843-4243, USA
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22
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Diaz-Herrera P, García-Castellano JM, Torres A, Morcuende JA, Calbet JA, Sarrat R. Effect of high-intensity running in rectus femoris muscle fiber in rats. J Orthop Res 2001; 19:229-32. [PMID: 11347695 DOI: 10.1016/s0736-0266(00)00031-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The effect of a 12-week high-intensity intermittent exercise program on fiber type composition and the oxidative capacity of rectus femoris skeletal muscle from 20 male Wistar rats (Trained, n = 10; Sedentary, n = 10) was histochemically determined. The training exercise program was developed in a motorized treadmill. It consisted of four running bouts of 2 min duration at 48 m/min, alternated with recovery intervals of 4 min. Training increased relative cross-sectional area of oxidative fibers (I, IIA, IIX) and decreased the same parameter in type IIB non-oxidative fibers (P < 0.001). Our results suggest that this type of strength exercise program is enough to induce changes in muscle fiber composition. This opens a possibility to use this kind of exercise in preventing and treating muscle atrophy.
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Affiliation(s)
- P Diaz-Herrera
- Departamento de Morfología, Facultad de Medicina, Universidad de Las Palmas de Gran Canaria, Spain.
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23
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Abstract
The effects of water deprivation on peripheral nerve and muscle function were investigated in flexor digitorum superficialis muscle of control and diabetic mice. Twenty mice (30 g average body weight) were injected once with streptozotocin solution (200 mg/kg) to induce experimental diabetes and another 20 mice of similar body weight served as controls. Two weeks later, comparative analyses of in situ muscle isometric contractile characteristics were performed by direct muscle stimulation and indirect nerve stimulation (at 1, 5 and 30 Hz) in urethane-anesthetized (2 mg/g, i.p.) control and diabetic mice. One day prior to the experiments, 10 control and 10 diabetic mice were deprived of water. The study contained four groups: hydrated (H) control, dehydrated (DH) control, H diabetic and DH diabetic. There were no significant differences in synaptic delay or twitch tension between H control and DH control. Comparing H control and H diabetic groups, no differences were noticed in synaptic delay or twitch tension; except at 30 Hz where twitch tension was reduced in H diabetic mice. Significant differences were observed when comparing DH control and DH diabetic mice. DH diabetic showed a significant increase in synaptic delay (from 7.4 to 9.3 ms) and a significant decrease in twitch tension evoked either by indirect nerve or by direct muscle stimulation (from 4.4 g to 1.9 g and from 4.4 g to 2.3 g, respectively). These results revealed that water deprivation enhances diabetes effects at the neuromuscular junction and at the muscle leading to further complication of neuromyopathy.
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Affiliation(s)
- M A Fahim
- Department of Physiology, Faculty of Medicine, UAE University, Al Ain, United Arab Emirates
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Klueber KM, Feczko JD. Ultrastructural, histochemical, and morphometric analysis of skeletal muscle in a murine model of type I diabetes. Anat Rec (Hoboken) 1994; 239:18-34. [PMID: 8037375 DOI: 10.1002/ar.1092390104] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
BACKGROUND Since peripheral nerves are damaged in diabetes mellitus, morphological changes occur within the diabetic muscle in response to the diabetic neuropathy. The aim of this study was to examine the extensor digitorum longus (EDL) from a 42-day streptozotocin-induced diabetic Swiss Webster mouse (STZ) and compare the muscle morphology and histochemistry to age-matched, nondiabetic controls. METHODS The EDL was evaluated using electron microscopy in order to investigate the morphological integrity of the myofibers and neuromuscular junctions. Histochemical analysis was completed using the myofibrillar CA(++)-ATPase reaction of Doriguzzi et al. (1983. Histochemistry, 79:289-294) for use in computer-assisted morphometric analysis of fiber size using Bioquant System 4 software. RESULTS Ultrastructural analysis of the diabetic EDL (N = 5, 225 myofibers/animal) showed a significant number of abnormal myofibers, exhibiting various degrees of degeneration, signs of denervation, and necrosis. The STZ myofibers exhibited excessive lipid accumulations and abnormal mitochondrial arrangements. Histochemical analysis of the STZ EDL revealed a significant shift in fiber type profile (53.6% type 2A and 46.4% type 2B- STZ myofibers; 47.5% type 2A, 52.5% type 2B nondiabetic controls). Morphometric analysis of myofiber size by fiber type (200 myofibers/muscle/fiber type) indicated a significant decrease in myofiber size for both type 2A and type 2B fibers in the STZ diabetic mouse. CONCLUSION The degeneration and necrosis of myofibers concomitant with the sever atrophy of both the type 2A and 2B myofibers in the STZ muscle could account for the functional alterations seen in diabetic muscle.
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Affiliation(s)
- K M Klueber
- Department of Anatomical Sciences and Neurobiology, University of Louisville School of Medicine, Kentucky 40292
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25
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Klueber KM, Porta DJ. Cytoarchitecture of diabetic myopathy during the pathogenesis of the disease: Fast versus slow muscle. Clin Anat 1994. [DOI: 10.1002/ca.980070606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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