Cellular adaptations of skeletal muscles to cyclosporine

1998 ◽  
Vol 84 (6) ◽  
pp. 1967-1975 ◽  
Author(s):  
Manmohan S. Biring ◽  
Mario Fournier ◽  
David J. Ross ◽  
Michael I. Lewis
Keyword(s):  
Myosin Heavy Chain ◽  
Heavy Chain ◽  
Cellular Response ◽  
Myosin Heavy Chain Isoforms ◽  
Male Rats ◽  
Type I ◽  
Solid Organ ◽  
Fiber Types ◽  
Cross Sectional ◽  
Final Body Weight

The aim of this study was to evaluate the cellular response of the diaphragm, extensor digitorum longus (EDL), and soleus (Sol) muscles to clinically relevant doses of cyclosporine administered to male rats over 4 wk. Control rats were provided with vehicle only. Muscle fiber types, cross-sectional areas, indexes of capillarity, and succinate dehydrogenase (SDH) activity were determined by quantitative histochemistry. Myosin heavy chain isoforms were identified by SDS-PAGE, and their proportions were measured by scanning densitometry. Serum cyclosporine level, 20–24 h after the last dose of cyclosporine, was 145 ± 81 ng/ml. Final body weight and muscle mass were similar between the cyclosporine and control groups. In the diaphragm, EDL, and Sol, no differences were observed between the groups with regard to fiber type proportions, fiber cross-sectional areas, and proportions of myosin heavy chain isoforms. In the EDL, reductions, both in SDH activity in type I, IIx, and IIb fibers (−26 to −37%) and in indexes of capillarity (−18 to −37%), were noted. In the Sol, SDH activity and capillarity were similar between the groups. In the diaphragm of cyclosporine-treated rats, there was significant reduction in the number of capillaries around individual fibers (−5%), whereas levels of SDH activity tended to be lower. This suggests that activation history may in part determine muscle-specific responses to cyclosporine. We speculate that reduced oxidative activity and capillarity of some limb muscles contribute to reduced exercise capacity and the “deconditioned state” observed in patients receiving cyclosporine after successful solid-organ transplantation.

Myosin Heavy Chain Composition in Human Masticatory Muscles by Immunohistochemistry and Gel Electrophoresis

2003 ◽  
Vol 51 (1) ◽  
pp. 113-119 ◽  
Author(s):  
J.A.M. Korfage ◽  
T.M.G.J. Van Eijden
Keyword(s):  
Myosin Heavy Chain ◽  
Correlation Coefficient ◽  
Heavy Chain ◽  
Fiber Type ◽  
Masticatory Muscles ◽  
Digastric Muscle ◽  
Type I ◽  
Fiber Types ◽  
Hybrid Fibers ◽  
Cross Sectional

In this study we compared the immunohistochemically quantified fiber type area with the myosin heavy chain (MyHC) contents of a bundle of fibers from a human masticatory muscle. The total cross-sectional areas were determined immunohistochemically for the three major fiber types (I, IIA, and IIX) in bundles of fibers ( n = 42) taken from the anterior and posterior belly of the human digastric muscle ( n = 7). The relative MyHC contents of the same fiber bundles were determined electrophoretically (MyHC-I, -IIA, and -IIX; anterior, 32%, 35%, and 33%; posterior, 39%, 42%, and 19%) and compared with the immunohistochemical data (MyHC-I, -IIA, and -IIX; anterior, 32%, 31%, and 37%; posterior, 39%, 45%, and 15%). No significant differences were seen in the mean fiber type distribution between the two techniques; the correlation coefficient ranged from 0.71 to 0.96. The correlation coefficient was higher for MyHC type I and MyHC type IIX than for MyHC type IIA. The MyHC contents of single fibers taken from the posterior belly indicated that many fibers in this belly co-express MyHC-IIA and MyHC-IIX. Despite the presence of these hybrid fibers, the correspondence between both methods was relatively large.

Distribution of myosin heavy chain isoforms in non-weight-bearing rat soleus muscle fibers

1996 ◽  
Vol 81 (6) ◽  
pp. 2540-2546 ◽  
Author(s):  
Robert J. Talmadge ◽  
Roland R. Roy ◽  
V. Reggie Edgerton
Keyword(s):  
Myosin Heavy Chain ◽  
Soleus Muscle ◽  
Heavy Chain ◽  
De Novo ◽  
Weight Bearing ◽  
Muscle Fibers ◽  
Myosin Heavy Chain Isoforms ◽  
Hindlimb Suspension ◽  
Type I ◽  
Rat Soleus Muscle

Talmadge, Robert J., Roland R. Roy, and V. Reggie Edgerton.Distribution of myosin heavy chain isoforms in non-weight-bearing rat soleus muscle fibers. J. Appl. Physiol. 81(6): 2540–2546, 1996.—The effects of 14 days of spaceflight (SF) or hindlimb suspension (HS) (Cosmos 2044) on myosin heavy chain (MHC) isoform content of the rat soleus muscle and single muscle fibers were determined. On the basis of electrophoretic analyses, there was a de novo synthesis of type IIx MHC but no change in either type I or IIa MHC isoform proportions after either SF or HS compared with controls. The percentage of fibers containing only type I MHC decreased by 26 and 23%, and the percentage of fibers with multiple MHCs increased from 6% in controls to 32% in HS and 34% in SF rats. Type IIx MHC was always found in combination with another MHC or combination of MHCs; i.e., no fibers contained type IIx MHC exclusively. These data suggest that the expression of the normal complement of MHC isoforms in the adult rat soleus muscle is dependent, in part, on normal weight bearing and that the absence of weight bearing induces a shift toward type IIx MHC protein expression in the preexisting type I and IIa fibers of the soleus.

Enzymatic plasticity of medial gastrocnemius fibers in the adult chronic spinal cat

1990 ◽  
Vol 259 (3) ◽  
pp. C507-C514 ◽  
Author(s):  
B. Jiang ◽  
R. R. Roy ◽  
V. R. Edgerton
Keyword(s):  
Myosin Heavy Chain ◽  
Heavy Chain ◽  
Fiber Type ◽  
Motor Units ◽  
Glycolytic Enzyme ◽  
Medial Gastrocnemius ◽  
Fiber Types ◽  
Cross Sectional ◽  
Fast Myosin ◽  
Weight Support

The metabolic plasticity of single fibers in adult cat medial gastrocnemius (MG) 6 mo after complete spinal cord transection (Sp) at T12-T13 was studied. Some Sp cats were trained to weight support (Sp-WS) 30 min/day beginning 1 mo posttransection. Cross-sectional area, succinate dehydrogenase (SDH), alpha-glycerophosphate dehydrogenase (GPD), and myofibrillar adenosinetriphosphatase (ATPase) activities were determined in fibers identified in frozen serial sections. Fibers were categorized as light or dark based on myosin ATPase staining, alkaline preincubation. The percentage of dark ATPase fibers was higher in Sp and Sp-WS (approximately 85%) than in control (approximately 60%). All dark ATPase fibers reacted positively to a fast myosin heavy chain monoclonal antibody. In both spinal groups, a higher percentage of dark ATPase fibers reacted to both fast and slow myosin heavy chain antibodies than in controls. Neither Sp nor Sp-WS cats showed fiber atrophy. Compared with control, SDH activity was decreased in both fiber types of Sp cats. Daily weight-support training ameliorated this adaptation. There were no differences among the three groups in mean GPD and ATPase activities for either fiber type. There was a slight tendency, however, for spinal cats to have higher GPD and ATPase activities (independent of type) than control, probably reflecting the larger proportion of dark ATPase fibers in these cats. These observations indicate that 6 mo after spinalization in adult cats, some of the fibers of a fast muscle became "faster" and developed oxidative and glycolytic enzyme profiles that normally are exhibited in fast fatigable motor units.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of starvation and refeeding on adult male rat diaphragm contractility, fatigue, and fiber types

1993 ◽  
Vol 74 (2) ◽  
pp. 742-749 ◽  
Author(s):  
D. J. Prezant ◽  
D. E. Valentine ◽  
H. H. Kim ◽  
E. I. Gentry
Keyword(s):  
Fatigue Resistance ◽  
Cross Sectional Area ◽  
Male Rats ◽  
Male Rat ◽  
Type I ◽  
Fiber Types ◽  
Type Ii ◽  
Sectional Area ◽  
Cross Sectional ◽  
Type Ii Fibers

The effects of 4.5 days of acute starvation, either alone or followed by refeeding (ad libitum), on diaphragm contractility, fatigue, and fiber types were studied in male rats. Contractility and fatigue resistance indexes were measured in an in vitro costal diaphragm strip preparation with direct stimulation at 37 degrees C. Compared with controls, starvation produced a 28 +/- 1% (P < 0.001) reduction in body weight and an 18 +/- 4% (P < 0.001) reduction in costal diaphragm weight. Twitch and tetanic tensions (normalized for weight or cross-sectional area) were not reduced by starvation. Starvation produced significant increases in fatigue resistance indexes after a 5-Hz stimulation paradigm but not after a 100-Hz paradigm, supporting the hypothesis that fatigue resistance is dependent on the energy demand of a given paradigm. The proportions of type I and type II fibers were similar between diaphragms of starved and control rats, but the cross-sectional area of type II fibers decreased significantly by 18 +/- 7% (P < 0.01). Thus, despite the significant decrease in diaphragm weight after starvation, contractility was preserved and fatigue resistance was increased (low-output paradigm). This is consistent with the decrease in type II fiber area. Refeeding restored all parameters so that there were no longer significant differences in body or diaphragm weight, contractility, fatigue, or fiber types.

Myosin heavy chain isoforms of human muscle after short-term spaceflight

1995 ◽  
Vol 78 (5) ◽  
pp. 1740-1744 ◽  
Author(s):  
M. Y. Zhou ◽  
H. Klitgaard ◽  
B. Saltin ◽  
R. R. Roy ◽  
V. R. Edgerton ◽  
...  
Keyword(s):  
Myosin Heavy Chain ◽  
Heavy Chain ◽  
Space Shuttle ◽  
Vastus Lateralis ◽  
Muscle Fibers ◽  
Rapid Change ◽  
Myosin Heavy Chain Isoforms ◽  
Single Fiber ◽  
Type I ◽  
Type Ii

The influence of microgravity on the myosin phenotype of skeletal muscle fibers in the vastus lateralis of eight crew members was studied before and after 5-day (n = 3) and 11-day (n = 5) spaceflights (space shuttle flights: STS-32, -33 and -34). Single-fiber electrophoresis analyses showed that the proportion of fibers expressing only slow (type I) myosin heavy chain (MHC) in the vastus lateralis was significantly lower after than before 11 days of spaceflight. Although the family of type II MHC isoforms was elevated post- compared with preflight, the distribution among the isoforms of type II MHC was not statistically different. Based on monoclonal and polyclonal antibodies specific for three adult MHC isoforms and single-fiber electrophoresis, approximately 3% of the fibers analyzed coexpressed all three adult MHC isoforms. The results from immunohistochemical staining with two different sets of antibodies indicate a reduction in the percentage of fibers expressing type I MHC as a result of spaceflight. The mean difference, however, was significant only when the fibers were categorized simply as type I or II. These changes appeared to be highly individualized among the astronauts. These results suggest that a rapid change in MHC isoform expression can occur in some muscle fibers after a relatively brief exposure to spaceflight.

scholarly journals Evaluation of Myosin Heavy Chain Isoforms in Biopsied Longissimus Thoracis Muscle for Estimation of Meat Quality Traits in Live Pigs

Animals ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 9
Author(s):  
Min Young Park ◽  
Youn-Chul Ryu ◽  
Chung-Nam Kim ◽  
Kyung-Bo Ko ◽  
Jun-Mo Kim
Keyword(s):  
Myosin Heavy Chain ◽  
Meat Quality ◽  
Muscle Fiber ◽  
Heavy Chain ◽  
Rapid Identification ◽  
Poor Quality ◽  
Myosin Heavy Chain Isoforms ◽  
Type I ◽  
Fiber Number ◽  
Muscle Fiber Number

Estimating meat quality prior to slaughter will be beneficial for the rapid identification of specific traits or poor quality pork compared to a conventional assessment at postmortem. In this study, we identified and quantified myosin heavy chain (MHC) isoforms from a biopsied longissimus thoracis muscle of pigs, and determined their correlation with postmortem muscle fiber characteristics and meat quality. MHC slow and fast isoforms proportions from biopsied samples correlated with postmortem percentage of type I and type IIB muscle fibers, respectively (p < 0.05). The percentage of the biopsied MHC slow isoform showed a positive correlation with pH at 45 min postmortem, and negative correlations with filter-paper fluid uptake and drip loss in pork (p < 0.05). Furthermore, clustering the pigs into three groups based on the biopsied MHC isoform proportions was not only significantly associated with muscle fiber number and proportions of muscle fiber area, but also correlated with pH at 45 min postmortem and the National Pork Producers Council color score (p < 0.05). Collectively, our findings indicate that the biopsied MHC isoforms serve as parameter for estimating meat quality, with the association between the higher proportion of MHC slow isoforms and pH at 45 min postmortem in particular being indicative of better pork quality.

scholarly journals Myofibril and Mitochondrial Area Changes in Type I and II Fibers Following 10 Weeks of Resistance Training in Previously Untrained Men

2021 ◽  
Vol 12 ◽  
Author(s):  
Bradley A. Ruple ◽  
Joshua S. Godwin ◽  
Paulo H. C. Mesquita ◽  
Shelby C. Osburn ◽  
Casey L. Sexton ◽  
...  
Keyword(s):  
Resistance Training ◽  
Myosin Heavy Chain ◽  
Heavy Chain ◽  
Vastus Lateralis ◽  
Thigh Muscle ◽  
Vastus Lateralis Muscle ◽  
Type I ◽  
Cross Sectional ◽  
Lateralis Muscle ◽  
Actin Protein

Resistance training increases muscle fiber hypertrophy, but the morphological adaptations that occur within muscle fibers remain largely unresolved. Fifteen males with minimal training experience (24±4years, 23.9±3.1kg/m2 body mass index) performed 10weeks of conventional, full-body resistance training (2× weekly). Body composition, the radiological density of the vastus lateralis muscle using peripheral quantitative computed tomography (pQCT), and vastus lateralis muscle biopsies were obtained 1week prior to and 72h following the last training bout. Quantification of myofibril and mitochondrial areas in type I (positive for MyHC I) and II (positive for MyHC IIa/IIx) fibers was performed using immunohistochemistry (IHC) techniques. Relative myosin heavy chain and actin protein abundances per wet muscle weight as well as citrate synthase (CS) activity assays were also obtained on tissue lysates. Training increased whole-body lean mass, mid-thigh muscle cross-sectional area, mean and type II fiber cross-sectional areas (fCSA), and maximal strength values for leg press, bench press, and deadlift (p&lt;0.05). The intracellular area occupied by myofibrils in type I or II fibers was not altered with training, suggesting a proportional expansion of myofibrils with fCSA increases. However, our histological analysis was unable to differentiate whether increases in myofibril number or girth occurred. Relative myosin heavy chain and actin protein abundances also did not change with training. IHC indicated training increased mitochondrial areas in both fiber types (p=0.018), albeit CS activity levels remained unaltered with training suggesting a discordance between these assays. Interestingly, although pQCT-derived muscle density increased with training (p=0.036), suggestive of myofibril packing, a positive association existed between training-induced changes in this metric and changes in mean fiber myofibril area (r=0.600, p=0.018). To summarize, our data imply that shorter-term resistance training promotes a proportional expansion of the area occupied by myofibrils and a disproportional expansion of the area occupied by mitochondria in type I and II fibers. Additionally, IHC and biochemical techniques should be viewed independently from one another given the lack of agreement between the variables assessed herein. Finally, the pQCT may be a viable tool to non-invasively track morphological changes (specifically myofibril density) in muscle tissue.

Effects of long-term continuous respiratory resistive loading on rat diaphragm function and structure

1993 ◽  
Vol 74 (3) ◽  
pp. 1212-1219 ◽  
Author(s):  
D. J. Prezant ◽  
T. K. Aldrich ◽  
B. Richner ◽  
E. I. Gentry ◽  
D. E. Valentine ◽  
...  
Keyword(s):  
Fatigue Resistance ◽  
Cross Sectional Area ◽  
Male Rats ◽  
Internal Diameter ◽  
Type I ◽  
Fiber Types ◽  
Sectional Area ◽  
Cross Sectional ◽  
Resistive Loading

The effects of long-term (24- to 28-wk) continuous respiratory resistive loading on diaphragm mass, contractility, fatigue, and fiber types were studied in male rats. Increased respiratory resistance was produced by extratracheal banding, and results were compared with sham-operated pair-fed controls. At the time the animals were killed, banded tracheal segment internal diameter was reduced by 57% of control values. Diaphragm surface area and muscle mass (normalized for body mass) increased by 19% of control values. Isometric diaphragm contractility and fatigue resistance indexes were measured using an in vitro diaphragm costal strip preparation at 37 degrees C. Twitch and tetanic stimulations were evoked using direct stimulation. Compared with controls, baseline tensions (normalized for diaphragm cross-sectional area) were significantly decreased at low frequencies. Fatigue resistance (endurance) indexes were significantly increased at all frequencies. These findings were consistent with observed increases in number and cross-sectional area of type I (low-tension high-endurance) fibers. We conclude that the diaphragm adapts to chronic long-term resistive loads by sacrificing peak tensions for an increase in endurance capacity.

Enhancement of hybrid-fiber types in rat soleus muscle after clenbuterol administration during hindlimb unloading

2004 ◽  
Vol 82 (5) ◽  
pp. 311-318 ◽  
Author(s):  
F Picquet ◽  
L De-Doncker ◽  
M Falempin
Keyword(s):  
Myosin Heavy Chain ◽  
Heavy Chain ◽  
Fiber Type ◽  
Myosin Heavy Chain Isoforms ◽  
Hindlimb Unloading ◽  
Fiber Types ◽  
Myosin Isoforms ◽  
Fast Myosin ◽  
Contractile Parameters ◽  
Fast Myosin Heavy Chain

Our objective was to determine the effects of a clenbuterol (CB) treatment orally administered (2 mg per kg) to rats submitted to 14 days of hindlimb unloading (HU). The morphological and the contractile properties as well as the myosin heavy chain isoforms contained in each fiber type were determined in whole soleus muscles. As classically described after HU, a decrease in muscle wet weight and in body mass associated with a loss of muscular force, an evolution of the contractile parameters towards those of a fast muscle type, and the emergence of fast myosin heavy chain isoforms were observed. The CB treatment in the HU rats helped reduce the decrease in 1) muscle and body weights, 2) force and 3) the proportion of slow fibers, without preventing the emergence of fast myosin isoforms. Clenbuterol induced a complex remodelling of the muscle typing promoting the combination of both slow and fast myosin isoforms within one fiber. To conclude, our data demonstrate that CB administration partially counteracts the effects produced by HU, and they allow us to anticipate advances in the treatment of muscular atrophy.Key words: β2 agonist, clenbuterol, soleus, contractile parameters, myosin, immunohistochemistry, simulated microgravity, countermeasure.

Sign in / Sign up

Export Citation Format

Share Document