Role of weight-bearing function on expression of myosin isoforms during regeneration of rat soleus muscles

Bigard, Xavier; Merino, D.; Serrurier, B.; Lienhard, F.; Guezennec, Y.; Bockhold, K.; Whalen, Robert G.

doi:10.1152/ajpcell.1996.270.3.c763

Cited by 34 publications

(39 citation statements)

References 26 publications

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“…The continued weight-bearing activity of the muscle in the days following the downhill exercise, and/ or the intrinsic nature of, and the in¯uence of environmental factors on the satellite cells participating in the ®bre reformation during this time, may have contributed to the observed increases in MHCd Bigard et al 1996). The co-expression of MHCd with MHCs and/or MHCf within ®bres suggests that the MHCd was synthesized as a supplement to the original adult isoform composition.…”

Section: Discussionmentioning

confidence: 99%

Expression of developmental myosin and morphological characteristics in adult rat skeletal muscle following exercise-induced injury

et al. 1999

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The extent and stability of the expression of developmental isoforms of myosin heavy chain (MHCd), and their association with cellular morphology, were determined in adult rat skeletal muscle fibres following injury induced by eccentrically-biased exercise. Adult female Wistar rats [274 (10) g] were either assigned as non-exercised controls or subjected to 30 min of treadmill exercise (grade, -16 degrees; speed, 15 m x min(-1)), and then sacrificed following 1, 2, 4, 7, or 12 days of recovery (n = 5-6 per group). Histologically and immunohistologically stained serial, transverse cryosections of the soleus (S), vastus intermedius (VI), and tibialis anterior (TA) muscles were examined using light microscopy and digital imaging. Fibres staining positively for MHCd (MHCd+) were seldom detected in the TA. In the VI and S, higher proportions of MHCd+ fibres (0.8% and 2.5%, respectively) were observed in rats at 4 and 7 days post-exercise, in comparison to all other groups combined (0.2%, 1.2%; P< or = 0.01). In S, MHCd+ fibres were observed less frequently by 12 days (0.7%) than at 7 days (2.6%) following exercise. The majority (85.1%) of the MHCd+ fibres had morphological characteristics indicative of either damage, degeneration, repair or regeneration. Most of the MHCd+ fibres also expressed adult slow, and/or fast myosin heavy chain. Quantitatively, the MHCd+ fibres were smaller (< 2500 microm2) and more angular than fibres not expressing MHCd. Thus, there was a transient increase in a small, but distinct population of MHCd+ fibres following unaccustomed, functional exercise in adult rat S and VI muscles. The observed close coupling of MHCd expression with morphological changes within muscle fibres suggests that these characteristics have a common, initial exercise-induced injury-related stimulus.

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Section: Discussionmentioning

confidence: 99%

Expression of developmental myosin and morphological characteristics in adult rat skeletal muscle following exercise-induced injury

et al. 1999

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“…Because regenerating myofibres account for a not negligible subpopulation of all fibres in SOL muscle, this finding raises the question of whether degeneration-regeneration could play a role in muscle type transformation that occurs during recovery following HS. It has been suggested that the control of myosin expression in muscles comprising mainly regenerating fibres is more homogeneous and more complete than in muscles composed of non-regenerated fibres (Bigard et al 1996). It is thus possible that the increased accumulation of slow MHC during recovery after HS might be partly related to the replacement of degenerated fibres by newly formed fibres that demonstrate a high degree of plasticity with respect to MHC phenotype.…”

Section: Discussionmentioning

confidence: 99%

Quantitative assessment of degenerative changes in soleus muscle after hindlimb suspension and recovery

Bigard

Merino²,

Lienhard³

et al. 1997

European Journal of Applied Physiology

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The aim of this study was to quantify the degenerative and regenerative changes in rat soleus muscle resulting from 3-week hindlimb suspension at 45 degrees tilt (HS group, n = 8) and 4-week normal cage recovery (HS-R group, n = 7). Degenerative changes were quantified by microscope examination of muscle cross sections, and the myosin heavy chain (MHC) composition of soleus muscles was studied by sodium dodecyl sulphate polyacrylamide gel electrophoresis. At the end of 3-week hindlimb suspension, histological signs of muscle degenerative changes were detected in soleus muscles. There was a significant variability in the percentage of fibres referred to as degenerating (%dg) in individual animals in the HS group [%dg = 8.41 (SEM 0.5)%, range 4.66%-14.08%]. Moreover, %dg varied significantly along the length of the soleus muscle. The percentage of fibres with internal nuclei was less than %dg in HS-soleus muscles [4.12 (SEM 0.3)%, range 1.24%-8.86%]. In 4-week recovery rats, the greater part of the fibres that were not referred to as normal, retained central nuclei [15.8 (SEM 2.2)%, range 6.2%-21.1%]. A significant increase in the slow isoform of MHG was recorded in the HS-R rats, compared to muscles from age-matched rats (P < 0.01). These results would suggest that a cycle of myofibre degeneration-regeneration occurred during HS and passive recovery, and that the increased accumulation of slow MHC observed in soleus muscles after recovery from HS could be related to the prevalence of newly formed fibres.

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“…A reduced weight-bearing function inhibits both growth and dierentiation of the regenerating soleus muscle (Esser and White 1995). Muscle mass growth (Esser and White 1995) and accumulation of mature (slow) myosin isoform or MHC-1 were decreased by hypokinesia and hypodynamia applied during regeneration of soleus muscle (Bigard et al 1996b;Esser and White 1995). Studies also reported that endurance exercise aects the muscle variables during regeneration (Bigard et al 1996a;Clark et al 1989;Esser and White 1995;White et al 1984).…”

Section: Introductionmentioning

confidence: 98%

Effect of increased physical activity on growth and differentiation of regenerating rat soleus muscle

Ferry¹,

Noirez²,

Salah³

et al. 1997

European Journal of Applied Physiology

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Our purpose was to determine the effect of physical exercise on growth and differentiation during regeneration of a slow-twitch muscle. Degeneration/regeneration of the left soleus muscles of Wistar female rats was induced by injection of a snake venom. Muscular differentiation was studied by monitoring the sequential expression of the various myosin heavy chain isoforms (MHCs). Rats were assigned to one of two groups: cage sedentary (n = 14) or exercised (n = 16). The exercise programme began 1-day post-injection and the rats ran 1 h/day on a motorized treadmill. Then, 9 and 25 days after venom treatment, the soleus MHC phenotype as determined by immunohistology, electrophoresis and immunoblotting, was studied. At 25 days the expression of MHCs by regenerating soleus was not changed by the increased level of physical activity (P > 0.05). Exercised and sedentary regenerating muscles contained similar numbers of type-I fibres (100% of total fibres), levels of MHC-1 (85.4 and 89.5% of total MHCs), MHC-2a and M/HC-2x/d and their fibres expressed MHC-1 (100% of total fibres) and MHC-2 (45-50%) in the same way. Moreover, the masses of regenerating and nonregenerating soleus were significantly increased by physical exercise (P < 0.02). At 9 days no effect of muscular exercise was found. In conclusion, endurance exercise did not alter differentiation of regenerating soleus. Moreover regenerating soleus can respond to increased physical activity by enhancing its mass in the same way as mature muscle.

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Role of weight-bearing function on expression of myosin isoforms during regeneration of rat soleus muscles

Cited by 34 publications

References 26 publications

Expression of developmental myosin and morphological characteristics in adult rat skeletal muscle following exercise-induced injury

Expression of developmental myosin and morphological characteristics in adult rat skeletal muscle following exercise-induced injury

Quantitative assessment of degenerative changes in soleus muscle after hindlimb suspension and recovery

Effect of increased physical activity on growth and differentiation of regenerating rat soleus muscle

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