In situ study of the sarcoplasmic reticulum function in control and mdx mouse diaphragm muscle

1998 ◽  
Vol 76 (12) ◽  
pp. 1161-1165 ◽  
Author(s):  
A Khammari ◽  
Y Péréon ◽  
S Baudet ◽  
J Noireaud
Keyword(s):  
Sarcoplasmic Reticulum ◽  
Recovery Process ◽  
Diaphragm Muscle ◽  
Calcium Handling ◽  
Mdx Mouse ◽  
Mdx Mice ◽  
Time Interval ◽  
Similar Time ◽  
Rapid Cooling ◽  
Significant Difference

Sarcoplasmic reticulum (SR) calcium handling in diaphragm was compared between mdx mice (7-8 weeks old) and age-matched controls. The total SR Ca2+ load was released from the SR by rapidly cooling muscle bundles from 22 to -1°C. The plateau amplitude of the rapid cooling contracture (RCC) was considered as an index of the SR Ca2+ content. The steady-state RCC amplitude was significantly lower by 50% in mdx bundles mainly because of a decreased capacity of the dystrophic diaphragm to generate maximal tension. There was no significant difference between either RCC time to peak or the time to half-relaxation of the transient, spike-like, contractile response induced by muscle rewarming. The recovery process of RCC was studied by using a paired RCC protocol. In both groups, at the shortest interval (10 s) between two RCCs, the amplitude of the second RCC was decreased by 25% compared with the first RCC. Increasing the time interval led to progressive monoexponential recovery of the second RCC with similar time constants in control and mdx diaphragm. These results indicate that the dystrophic process does not significantly alter SR Ca2+ uptake nor Ca2+ redistribution within the muscular cell.Key words: diaphragm, mdx, rapid cooling contracture, sarcoplasmic reticulum.

Diaphragm tension reduced in dystrophic mice by an oxidant, hypochlorous acid

2010 ◽  
Vol 88 (2) ◽  
pp. 130-140
Author(s):  
Aude Lafoux ◽  
Alexandra Divet ◽  
Pascal Gervier ◽  
Corinne Huchet-Cadiou
Keyword(s):  
Skeletal Muscle ◽  
Sarcoplasmic Reticulum ◽  
Hypochlorous Acid ◽  
Muscle Cells ◽  
Skeletal Muscle Cells ◽  
Diaphragm Muscle ◽  
Mdx Mouse ◽  
Mdx Mice ◽  
Skinned Fibres ◽  
Dystrophic Mice

In dystrophin-deficient skeletal muscle cells, in which Ca2+ homeostasis is disrupted and reactive oxygen species production is increased, we hypothesized that hypochlorous acid (HOCl), a strong H2O2-related free radical, damages contractile proteins and the sarcoplasmic reticulum. The aim of the present study was to investigate the effects of exposure to oxidative stress, generated by applying HOCl (100 µmol/L and 1 mmol/L), on the contractile function and sarcoplasmic reticulum properties of dystrophic mice. Experiments were performed on diaphragm muscle, which is severely affected in the mdx mouse, and the results were compared with those obtained in healthy (non-dystrophic) mice. In Triton-skinned fibres from C57BL/10 and mdx mice, 1 mmol/L HOCl increased myofibrillar Ca2+ sensitivity, but decreased maximal Ca2+-activated tension. In the presence of HOCl, higher concentrations of MgATP were required to produce rigor tensions. The interaction between HOCl and the Ca2+ uptake mechanisms was demonstrated using saponin-skinned fibres and sarcoplasmic reticulum vesicles. The results showed that HOCl, at micromolar or millimolar concentrations, can modify sarcoplasmic reticulum Ca2+ uptake and that this effect was more pronounced in diaphragm muscle from mdx mice. We conclude that in dystrophic diaphragm skeletal muscle cells, HOCl activates a cellular pathway that leads to an increase in the intracellular concentration of Ca2+.

Global/temporal gene expression in diaphragm and hindlimb muscles of dystrophin-deficient (mdx) mice

2002 ◽  
Vol 283 (3) ◽  
pp. C773-C784 ◽  
Author(s):  
Karl Rouger ◽  
Martine Le Cunff ◽  
Marja Steenman ◽  
Marie-Claude Potier ◽  
Nathalie Gibelin ◽  
...  
Keyword(s):  
Dystrophin Gene ◽  
Diaphragm Muscle ◽  
Mdx Mouse ◽  
Mdx Mice ◽  
First Year ◽  
Temporal Gene Expression ◽  
Cell Functions ◽  
Hindlimb Muscles ◽  
Genes Encoding ◽  
Dystrophin Protein

The mdx mouse is a model for human Duchenne muscular dystrophy (DMD), an X-linked degenerative disease of skeletal muscle tissue characterized by the absence of the dystrophin protein. The mdx mice display a much milder phenotype than DMD patients. After the first week of life when all mdx muscles evolve like muscles of young DMD patients, mdx hindlimb muscles substantially compensate for the lack of dystrophin, whereas mdx diaphragm muscle becomes progressively affected by the disease. We used cDNA microarrays to compare the expression profile of 1,082 genes, previously selected by a subtractive method, in control and mdx hindlimb and diaphragm muscles at 12 time points over the first year of the mouse life. We determined that 1) the dystrophin gene defect induced marked expression remodeling of 112 genes encoding proteins implicated in diverse muscle cell functions and 2) two-thirds of the observed transcriptomal anomalies differed between adult mdx hindlimb and diaphragm muscles. Our results showed that neither mdx diaphram muscle nor mdx hindlimb muscles evolve entirely like the human DMD muscles. This finding should be taken under consideration for the interpretation of future experiments using mdx mice as a model for therapeutic assays.

Intracellular calcium handling in ventricular myocytes from mdx mice

2007 ◽  
Vol 292 (2) ◽  
pp. H846-H855 ◽  
Author(s):  
Iwan A. Williams ◽  
David G. Allen
Keyword(s):  
Heart Failure ◽  
Protein Expression ◽  
Transient Receptor Potential ◽  
Ventricular Myocytes ◽  
Clinical Symptoms ◽  
Disease Process ◽  
Calcium Handling ◽  
Mdx Mouse ◽  
Mdx Mice ◽  
Age Related

Duchenne muscular dystrophy (DMD) is a lethal degenerative disease of skeletal muscle, characterized by the absence of the cytoskeletal protein dystrophin. Some DMD patients show a dilated cardiomyopathy leading to heart failure. This study explores the possibility that dystrophin is involved in the regulation of a stretch-activated channel (SAC), which in the absence of dystrophin has increased activity and allows greater Ca2+ into cardiomyocytes. Because cardiac failure only appears late in the progression of DMD, we examined age-related effects in the mdx mouse, an animal model of DMD. Ca2+ measurements using a fluorescent Ca2+-sensitive dye fluo-4 were performed on single ventricular myocytes from mdx and wild-type mice. Immunoblotting and immunohistochemistry were performed on whole hearts to determine expression levels of key proteins involved in excitation-contraction coupling. Old mdx mice had raised resting intracellular Ca2+ concentration ([Ca2+]i). Isolated ventricular myocytes from young and old mdx mice displayed abnormal Ca2+ transients, increased protein expression of the ryanodine receptor, and decreased protein expression of serine-16-phosphorylated phospholamban. Caffeine-induced Ca2+ transients showed that the Na+/Ca2+ exchanger function was increased in old mdx mice. Two SAC inhibitors streptomycin and GsMTx-4 both reduced resting [Ca2+]i in old mdx mice, suggesting that SACs may be involved in the Ca2+-handling abnormalities in these animals. This finding was supported by immunoblotting data, which demonstrated that old mdx mice had increased protein expression of canonical transient receptor potential channel 1, a likely candidate protein for SACs. SACs may play a role in the pathogenesis of the heart failure associated with DMD. Early in the disease process and before the onset of clinical symptoms increased, SAC activity may underlie the abnormal Ca2+ handling in young mdx mice.

scholarly journals Compared with that of MUFA, a high dietary intake of n-3 PUFA does not reduce the degree of pathology in mdx mice

2014 ◽  
Vol 111 (10) ◽  
pp. 1791-1800 ◽  
Author(s):  
Gregory C. Henderson ◽  
Nicholas P. Evans ◽  
Robert W. Grange ◽  
Marc A. Tuazon
Keyword(s):  
Skeletal Muscle ◽  
Oleic Acid ◽  
Muscle Disease ◽  
New Drugs ◽  
Arachidonic Acid Content ◽  
Mdx Mouse ◽  
Mdx Mice ◽  
Significant Difference ◽  
Pufa Diet ◽  
Mufa Diet

Duchenne muscular dystrophy (DMD) is a severe muscle disease that affects afflicted males from a young age, and the mdx mouse is an animal model of this disease. Although new drugs are in development, it is also essential to assess potential dietary therapies that could assist in the management of DMD. In the present study, we compared two diets, high-MUFA diet v. high-PUFA diet, in mdx mice. To generate the high-PUFA diet, a portion of dietary MUFA (oleic acid) was replaced with the dietary essential n-3 PUFA α-linolenic acid (ALA). We sought to determine whether ALA, compared with oleic acid, was beneficial in mdx mice. Consumption of the high-PUFA diet resulted in significantly higher n-3 PUFA content and reduced arachidonic acid content in skeletal muscle phospholipids (PL), while the high-MUFA diet led to higher oleate content in PL. Mdx mice on the high-MUFA diet exhibited 2-fold lower serum creatine kinase activity than those on the high-PUFA diet (P< 0·05) as well as a lower body fat percentage (P< 0·05), but no significant difference in skeletal muscle histopathology results. There was no significant difference between the dietary groups with regard to phosphorylated p65 (an inflammatory marker) in skeletal muscle. In conclusion, alteration of PL fatty acid (FA) composition by the high-PUFA diet made mdx muscle more susceptible to sarcolemmal leakiness, while the high-MUFA diet exhibited a more favourable impact. These results may be important for designing dietary treatments for DMD patients, and future work on dietary FA profiles, such as comparing other FA classes and dose effects, is needed.

Severe muscle dysfunction precedes collagen tissue proliferation in mdx mouse diaphragm

2003 ◽  
Vol 94 (5) ◽  
pp. 1744-1750 ◽  
Author(s):  
Catherine Coirault ◽  
Bernadette Pignol ◽  
Racquel N. Cooper ◽  
Gillian Butler-Browne ◽  
Pierre-Etienne Chabrier ◽  
...  
Keyword(s):  
Muscle Performance ◽  
Diaphragm Muscle ◽  
Mdx Mouse ◽  
Mdx Mice ◽  
Cycle Duration ◽  
Shortening Velocity ◽  
Tissue Proliferation ◽  
Mouse Diaphragm ◽  
Muscular Dysfunction ◽  
Time Cycle

After extensive necrosis, progressive diaphragm muscle weakness in the mdx mouse is thought to reflect progressive replacement of contractile tissue by fibrosis. However, little has been documented on diaphragm muscle performance at the stage at which necrosis and fibrosis are limited. Diaphragm morphometric characteristics, muscle performance, and cross-bridge (CB) properties were investigated in 6-wk-old control (C) and mdx mice. Compared with C, maximum tetanic tension and shortening velocity were 37 and 32% lower, respectively, in mdx mice (each P < 0.05). The total number of active CB per millimeter squared (13.0 ± 1.2 vs. 18.4 ± 1.7 × 109/mm2, P < 0.05) and the CB elementary force (8.0 ± 0.2 vs. 9.0 ± 0.1 pN, P < 0.01) were lower in mdx than in C. The time cycle duration was lower in mdx than in C (127 ± 18 vs. 267 ± 61 ms, P < 0.05). Percentages of fiber necrosis represented 2.8 ± 0.6% of the total muscle fibers, and collagen surface area occupied 3.6 ± 0.7% in mdx diaphragm. Our results pointed to severe muscular dysfunction in mdx mouse diaphragm, despite limited necrotic and fibrotic lesions.

Greater Susceptibility of the Sarcoplasmic Reticulum to H2O2 Injuries in Diaphragm Muscle from mdx Mice

2006 ◽  
Vol 318 (3) ◽  
pp. 1359-1367 ◽  
Author(s):  
Aude Lafoux ◽  
Alexandra Divet ◽  
Pascal Gervier ◽  
Corinne Huchet-Cadiou
Keyword(s):  
Sarcoplasmic Reticulum ◽  
Diaphragm Muscle ◽  
Mdx Mice

Contractile properties of diaphragm muscle segments from old mdx and old transgenic mdx mice

1997 ◽  
Vol 272 (6) ◽  
pp. C2063-C2068 ◽  
Author(s):  
G. S. Lynch ◽  
J. A. Rafael ◽  
R. T. Hinkle ◽  
N. M. Cole ◽  
J. S. Chamberlain ◽  
...  
Keyword(s):  
Life Span ◽  
Functional Properties ◽  
Transgenic Animal ◽  
Mouse Embryos ◽  
Diaphragm Muscle ◽  
Mdx Mouse ◽  
Mdx Mice ◽  
Dystrophin Expression ◽  
Structural And Functional Properties

Diaphragm muscles of young (4- to 6-mo-old) mdx mice show severe fiber necrosis and have normalized forces and powers 60 and 46% of the values for control C57BL/10 mice. In contrast, microinjection of mdx mouse embryos with a truncated dystrophin minigene has produced young transgenic mdx (tg-mdx) mice with a level of dystrophin expression and structural and functional properties of diaphragm muscle strips measured in vitro not different from those of control mice. Whether dystrophin expression and functional corrections persist for the life span of these animals is not know. We tested the null hypothesis that, in old (24 mo) tg-mdx mice, dystrophin expression is adequate and diaphragm muscle strips have forces and powers not different from values for diaphragm muscle strips from young tg-mdx mice or control mice. Compared with control values, diaphragm muscle strips from old mdx mice had normalized forces and powers of 48 and 31%, respectively. Expression of dystrophin persisted in diaphragm muscles of old tg-mdx mice, and functional properties were not different from diaphragm muscles of young tg-mdx or young or old control mice. These results suggest that, with a transgenic animal approach, dystrophin expression and functional corrections persist for the life span of the animals.

Stretch-activated calcium channel protein TRPC1 is correlated with the different degrees of the dystrophic phenotype in mdx mice

2011 ◽  
Vol 301 (6) ◽  
pp. C1344-C1350 ◽  
Author(s):  
Cíntia Yuri Matsumura ◽  
Ana Paula Tiemi Taniguti ◽  
Adriana Pertille ◽  
Humberto Santo Neto ◽  
Maria Julia Marques
Keyword(s):  
Calcium Channel ◽  
Transient Receptor Potential ◽  
Biceps Brachii ◽  
Receptor Potential ◽  
Diaphragm Muscle ◽  
Mdx Mouse ◽  
Mdx Mice ◽  
Blue Dye ◽  
Channel Protein ◽  
Transient Receptor

In Duchenne muscular dystrophy (DMD) and in the mdx mouse model of DMD, the lack of dystrophin is related to enhanced calcium influx and muscle degeneration. Stretch-activated channels (SACs) might be directly involved in the pathology of DMD, and transient receptor potential cation channels have been proposed as likely candidates of SACs. We investigated the levels of transient receptor potential canonical channel 1 (TRPC1) and the effects of streptomycin, a SAC blocker, in muscles showing different degrees of the dystrophic phenotype. Mdx mice (18 days old, n = 16) received daily intraperitoneal injections of streptomycin (182 mg/kg body wt) for 18 days, followed by removal of the diaphragm, sternomastoid (STN), biceps brachii, and tibialis anterior muscles. Control mdx mice ( n = 37) were injected with saline. Western blot analysis showed higher levels of TRPC1 in diaphragm muscle compared with STN and limb muscles. Streptomycin reduced creatine kinase and prevented exercise-induced increases of total calcium and Evans blue dye uptake in diaphragm and in STN muscles. It is suggested that different levels of the stretch-activated calcium channel protein TRPC1 may contribute to the different degrees of the dystrophic phenotype seen in mdx mice. Early treatment designed to regulate the activity of these channels may ameliorate the progression of dystrophy in the most affected muscle, the diaphragm.

SERCA-mediated calcium uptake in the DBA/2J vs C57BL/10 mdx models of Duchenne muscular dystrophy

2021 ◽  
Author(s):  
Riley EG Cleverdon ◽  
Kennedy C Whitley ◽  
Daniel M Marko ◽  
Sophie I Hamstra ◽  
Jessica L Braun ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Duchenne Muscular Dystrophy ◽  
Sarcoplasmic Reticulum ◽  
Muscular Dystrophy ◽  
Calcium Uptake ◽  
Late Onset ◽  
Mdx Mouse ◽  
Mdx Mice ◽  
Mild Phenotype ◽  
Serca Pump

The C57BL/10ScSn-Dmdmdx/J (C57 mdx) mouse is the most commonly used murine model of Duchenne muscular dystrophy (DMD) but displays a mild phenotype with a late onset, greatly limiting translatability to clinical research. In consequence, the D2.B10-Dmdmdx/J (D2 mdx) mouse was created and produces a more severe, early onset phenotype. Mechanistic insights of the D2 mdx phenotype have yet to be elucidated, specifically related to sarcoplasmic reticulum (SR) calcium (Ca2+) handling. In our study, we aimed to determine if SR Ca2+ handling differences in the D2 mdx versus the C57 mdx mouse could explain model phenotypes. Firstly, analyses determined that D2 mdx mice ambulate less and have weaker muscles, but have greater energy expenditure than C57 counterparts. SR Ca2+ handling measures determined that only D2 mdx mice have impaired SR calcium intake in the gastrocnemius, left ventricle and diaphragm. This was coupled with decrements in maximal sarco-endoplasmic reticulum Ca2+-ATPase (SERCA) activity and greater activation of the Ca2+-activated protease, calpain, in the gastrocnemius. Overall, our study is the first to determine that SR Ca2+ handling is impaired in the D2 mdx mouse, specifically at the level of the SERCA pump. 

scholarly journals N-acetylcysteine Decreases Fibrosis and Increases Force-Generating Capacity of mdx Diaphragm

Antioxidants ◽  
2019 ◽  
Vol 8 (12) ◽  
pp. 581 ◽  
Author(s):  
David P. Burns ◽  
Sarah E. Drummond ◽  
Dearbhla Bolger ◽  
Amélie Coiscaud ◽  
Kevin H. Murphy ◽  
...  
Keyword(s):  
Respiratory Muscle ◽  
Immune Cell ◽  
Muscle Performance ◽  
Diaphragm Muscle ◽  
Cell Infiltration ◽  
Mdx Mouse ◽  
Mdx Mice ◽  
Immune Cell Infiltration ◽  
Wild Type ◽  
Generating Capacity

Respiratory muscle weakness occurs due to dystrophin deficiency in Duchenne muscular dystrophy (DMD). The mdx mouse model of DMD shows evidence of impaired respiratory muscle performance with attendant inflammation and oxidative stress. We examined the effects of N-acetylcysteine (NAC) supplementation on respiratory system performance in mdx mice. Eight-week-old male wild type (n = 10) and mdx (n = 20) mice were studied; a subset of mdx (n = 10) received 1% NAC in the drinking water for 14 days. We assessed breathing, diaphragm, and external intercostal electromyogram (EMG) activities and inspiratory pressure during ventilatory and non-ventilatory behaviours. Diaphragm muscle structure and function, cytokine concentrations, glutathione status, and mRNA expression were determined. Diaphragm force-generating capacity was impaired in mdx compared with wild type. Diaphragm muscle remodelling was observed in mdx, characterized by increased muscle fibrosis, immune cell infiltration, and central myonucleation. NAC supplementation rescued mdx diaphragm function. Collagen content and immune cell infiltration were decreased in mdx + NAC compared with mdx diaphragms. The cytokines IL-1β, IL-6 and KC/GRO were increased in mdx plasma and diaphragm compared with wild type; NAC decreased systemic IL-1β and KC/GRO concentrations in mdx mice. We reveal that NAC treatment improved mdx diaphragm force-generating capacity associated with beneficial anti-inflammatory and anti-fibrotic effects. These data support the potential use of NAC as an adjunctive therapy in human dystrophinopathies.

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