Effects of Hindlimb Suspension with Stretched or Shortened Muscle Length on Contractile Properties of Rat Soleus

Ohira, Yoshinobu; Yoshinaga, Tetsutaro; Yasui, Wataru; Ohara, Makoto; Tanaka, Takato

doi:10.1123/jab.16.1.80

Cited by 14 publications

(6 citation statements)

References 15 publications

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“…During suspension, the ankle joint gradually assumes the position of plantar-flexion 7) , and SOL is shortened approximately 10 mm and EDL is lengthened 38) . It has been reported that atrophy of plantar flexors during suspension was prevented by fixation of the ankle joint in the dorsi-flexion position and passive stretch 39) . This means that weight-bearing during suspension induces passive dorsi-flexion of the ankle joint, leading to lengthening of SOL.…”

Section: Discussionmentioning

confidence: 99%

Effects of Intermittent Weight-Bearing and Clenbuterol on Disuse Atrophy of Rat Hindlimb Muscles

Yamazaki

2005

J Jpn Phys Ther Assoc

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Abstract. The present study was undertaken to evaluate the effects of intermittent weight-bearing (IWB) combined with β2-agonist clenbuterol (Cb) medication for suppressing muscle atrophy during progressive disuse atrophy. Male Wistar rats (age: 8weeks, body weight: 232 ± 14 g) were divided into a control group (CON) and an experimental group. The experimental group was further subdivided into a Cb medication group under normal conditions and a hindlimb unweighting (HU) treatment group. The HU treatment group was composed of four groups: HU treatment-only, HU treatment + IWB, HU treatment + Cb medication and HU treatment + IWB + Cb medication. IWB was performed by temporarily removing the suspension device for one hour daily. On Day 14, bilateral soleus muscle (SOL) and extensor digitorum longus muscle (EDL) were extracted. Muscles from the right side were used for the measurement of contractile properties (physiological functional evaluations). Muscles from the left side were used for histochemical and biochemical analysis. During HU, IWB combined with Cb medication worked to preserve the wet weight and relative weight of SOL as compared to CON. Its contractile properties were affected by weight-bearing, while the cross-sectional area of type I fiber and protein concentration were affected by Cb. This combined therapy had marked effects on the morphology of EDL, particularly on the cross-sectional area of type II fiber. The protein concentration and contractile properties of EDL were unaffected by this combined therapy. The effect of a combination of IWB and Cb medication was specific to fiber-type and region. The data suggested that 1) IWB was effective on functional aspects such as contractile properties and useful for physical therapy, 2) Cb medication exerted the atrophy-suppressive effect in morphological parameters and manifested less effect on functional aspects. The results in this study indicated the possibility of elevating the efficacy of IWB by Cb medication in SOL.

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Section: Discussionmentioning

confidence: 99%

Effects of Intermittent Weight-Bearing and Clenbuterol on Disuse Atrophy of Rat Hindlimb Muscles

Yamazaki

2005

J Jpn Phys Ther Assoc

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“…Tension is not developed by shortened plantarflexors, even when EMG is present [27]. A suspension-related atrophy of plantarflexors was prevented when the muscles were stretched passively by plaster fixing of the ankle joint at a dorsiflexed position [30]. It is also indicated that forced contraction through electrical stimulation is not beneficial if the muscles are shortened and tension is not developed.…”

Section: Experiments Imentioning

confidence: 99%

Regulation of the Properties of Rat Hind Limb Muscles Following Gravitational Unloading.

Ohira

Hanada²,

Kawano³

et al. 2002

JJP

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It has been reported that gravitational unloading by actual spaceflight [1][2][3] or simulation models, such as hind limb suspension of rats [3] or human bed rest [4,5] causes atrophy in antigravity muscles. These responses are more profound in slow-twitch than in fasttwitch fibers of ankle plantarflexor muscles [2,3]. It is clear that changes of the muscular properties following gravitational unloading are caused by the decreased normal activity. However, it is not necessarily known what the key factor is for such muscle-specific effects of gravitational unloading. Therefore the effects of various kinds of activities-such as electrical activity estimated by an electromyogram (EMG) recording, contractile activity induced by electrical stimulation at low or high frequencies, and length-related loading on the muscles-on the properties of hind limb muscles were studied in the present investigation.Leonard et al. [6] reported that the mean decrease of lean body mass in nine astronauts was 1.5 kg after 28-84 d of spaceflight, and 1.1 kg was due to water loss. In some studies, the absolute protein content, not Japanese Journal of Physiology, 52, 235-245, 2002 Key words: hind limb suspension, atrophy and growth failure, protein and water contents, electromyogram, muscle length. Abstract:The mechanisms responsible for the morphological and metabolic adaptation of skeletal muscles to the removal of antigravity activity were investigated in rats. Significant atrophy relative to the levels before suspension was induced in ankle plantarflexsors, may be due to a reduced tension production caused by decreased muscle length and electromyogram activity. Growth failure was significant in ankle dorsiflexors, although these muscles did not atrophy. Forced muscle contraction through electrical stimulation at 1 or 100 Hz during hind limb suspension generally had detrimental effects. The percent contribution of water loss to the suspension-related change in weight was 85, 88, and 93% in soleus, plantaris, and extensor digitorum longus, respectively. The total levels of both ␤-hydroxyacyl CoA dehydrogenase (HAD) and lactate dehydrogenase (LDH) were less in the suspended muscles than in the controls, having high positive correlations with the total protein content. The specific activity of HAD, but not of LDH, of the suspended muscles was lower than in the controls (25-61%). These data suggest that the cause of muscle atrophy and changes in metabolic properties may be a decreased tension development, not necessarily the reduction of electrical or contractile activity. Further, it is clearly suggested that electrical stimulation of a muscle group with different composition of fiber phenotype at a certain pattern or frequency is not suitable for the countermeasure. It is also suggested that the major cause of the decreased muscle weight was loss of water, even though protein content was also lowered after suspension. Moreover, the data suggest that the HAD level was affected more than the total protein content and LDH.

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“…Animal experiments performed in the early 1970s (Tabary et al, 1972;Williams and Goldspink, 1973) and later (Ohira et al, 2000) showed a loss of sarcomeres in series when muscles are immobilised in a shortened position. In humans, one common condition that places muscle-tendon units (MTUs) in a shortened position is high heel (HH) wearing.…”

Section: Introductionmentioning

confidence: 99%

On muscle, tendon and high heels

Csapo

Maganaris

Seynnes

et al. 2010

Journal of Experimental Biology

115

100

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SUMMARYWearing high heels (HH) places the calf muscle-tendon unit (MTU) in a shortened position. As muscles and tendons are highly malleable tissues, chronic use of HH might induce structural and functional changes in the calf MTU. To test this hypothesis, 11 women regularly wearing HH and a control group of 9 women were recruited. Gastrocnemius medialis (GM) fascicle length, pennation angle and physiological cross-sectional area (PCSA), the Achilles' tendon (AT) length, cross-sectional area (CSA) and mechanical properties, and the plantarflexion torque-angle and torque-velocity relationships were assessed in both groups. Shorter GM fascicle lengths were observed in the HH group (49.6±5.7mm vs 56.0±7.7mm), resulting in greater tendon-to-fascicle length ratios. Also, because of greater AT CSA, AT stiffness was higher in the HH group (136.2±26.5Nmm -1 vs 111.3±20.2Nmm -1). However, no differences in the GM PCSA to AT CSA ratio, torque-angle and torque-velocity relationships were found. We conclude that long-term use of high-heeled shoes induces shortening of the GM muscle fascicles and increases AT stiffness, reducing the ankle's active range of motion. Functionally, these two phenomena seem to counteract each other since no significant differences in static or dynamic torques were observed.

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Effects of Hindlimb Suspension with Stretched or Shortened Muscle Length on Contractile Properties of Rat Soleus

Cited by 14 publications

References 15 publications

Effects of Intermittent Weight-Bearing and Clenbuterol on Disuse Atrophy of Rat Hindlimb Muscles

Effects of Intermittent Weight-Bearing and Clenbuterol on Disuse Atrophy of Rat Hindlimb Muscles

Regulation of the Properties of Rat Hind Limb Muscles Following Gravitational Unloading.

On muscle, tendon and high heels

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