Journal of Applied Physiology, Vol 80, Issue 3 734-741, Copyright © 1996 by American Physiological Society

ARTICLES

Exercise and clenbuterol as strategies to decrease the progression of muscular dystrophy in mdx mice

E. E. Dupont-Versteegden
Department of Physiology, University of Texas Health Science Center at San Antonio 78284-7756, USA.

The effects of exercise and the combination of exercise and clenbuterol on progression of muscular dystrophy were studied in mdx mice. At 3 wk of age, mdx mice were randomly assigned to sedentary (MS), exercise (ME), or combined exercise and clenbuterol (MEC) groups. Clenbuterol was given in the drinking water (1.0-1.5 mg . kg body weight-1 . day-1), and exercise consisted of spontaneous running activity on exercise wheels. At 3 mo or 1 yr of age, ventilatory function, contractile properties, and morphological characteristics of the soleus (Sol) and diaphragm (Dia) muscles were measured. The mdx mice receiving clenbuterol ran less than the mice without clenbuterol. The combination of clenbuterol and exercise was associated with an increase in Sol muscle weight and a muscle weight-to-body weight ratio of 30-35% compared with the sedentary group and approximately 20% compared to exercise alone. Myosin and total protein concentrations of the Sol and Dia increased in the MEC group at 1 yr of age only. Normalized active tension was increased in the Dia at 1 yr of age in both the ME and MEC groups by approximately 30%. Absolute tetanic tension of the Sol was increased at both 3 mo and 1 yr of age in the MEC compared with the MS group. At 1 yr of age, there was an additional 23% increase compared with the ME group. Fatigability increased in the MEC group by approximately 25% in the Sol and Dia muscles at both ages compared with the MS and ME groups. Results indicate that exercise and exercise plus clenbuterol decrease the progression of muscular dystrophy. However, different mechanisms may be involved because the combination of clenbuterol and exercise resulted in increased fatigability and the development of deformities, whereas exercise alone did not. Therefore, clenbuterol may not be suitable for use in patients with muscular dystrophy.

This article has been cited by other articles:

				G. S. Lynch and J. G. Ryall Role of {beta}-Adrenoceptor Signaling in Skeletal Muscle: Implications for Muscle Wasting and Disease Physiol Rev, April 1, 2008; 88(2): 729 - 767. [Abstract] [Full Text] [PDF]

				C. L. Skura, E. G. Fowler, G. T. Wetzel, M. Graves, and M. J. Spencer Albuterol increases lean body mass in ambulatory boys with Duchenne or Becker muscular dystrophy Neurology, January 8, 2008; 70(2): 137 - 143. [Abstract] [Full Text] [PDF]

				E.L. van der Kooi, O.J.M. Vogels, R.J.G.P. van Asseldonk, E. Lindeman, J.C.M. Hendriks, M. Wohlgemuth, S.M. van der Maarel, and G.W. Padberg Strength training and albuterol in facioscapulohumeral muscular dystrophy Neurology, August 24, 2004; 63(4): 702 - 708. [Abstract] [Full Text] [PDF]

				J. M. Lang, K. A. Esser, and E. E. Dupont-Versteegden Altered Activity of Signaling Pathways in Diaphragm and Tibialis Anterior Muscle of Dystrophic Mice Experimental Biology and Medicine, June 1, 2004; 229(6): 503 - 511. [Abstract] [Full Text] [PDF]

				J. T. Kissel, M. P. McDermott, J. R. Mendell, W. M. King, S. Pandya, R. C. Griggs, and R. Tawil Randomized, double-blind, placebo-controlled trial of albuterol in facioscapulohumeral dystrophy Neurology, October 23, 2001; 57(8): 1434 - 1440. [Abstract] [Full Text] [PDF]

				A. Mokhtarian, J. P. Lefaucheur, P. C. Even, and A. Sebille Hindlimb immobilization applied to 21-day-old mdx mice prevents the occurrence of muscle degeneration J Appl Physiol, March 1, 1999; 86(3): 924 - 931. [Abstract] [Full Text] [PDF]