Title

 

Authors

R.F. Capogrosso¹, A. Cozzoli¹, V. Sblendorio¹, S. Gagliardi², V. Longo³, M. Montagnani², B. Nico³, A. De Luca¹.
 
¹Unit of Pharmacology, Dept of Pharmaco-biology, Faculty of Pharmacy, University of Bari, Italy; ²Dept of Pharmacology and Human Physiology, University of Bari, Italy; ³Dept of Human Anatomy and Hystology, University of Bari, Italy.

 

Abstract

X-linked mutations of the dystrophin gene lead to severe Duchenne muscular dystrophy (DMD) in humans and to dystrophic conditions in animals, as the mdx mouse (Hoffman & Dressman, 2001). Nowadays the sole drugs of clinical interest for DMD are glucocorticoids, although their use is restricted by the severe side effects (Bushby et al., 2007). Then an intense pre-clinical research is ongoing to identify effective and safer drugs. Although the molecular mechanisms leading to muscle degeneration in dystrophinopathies are not fully understood, a key role is played by inflammation and oxidative stress (Hoffman & Dressman, 2001). The aim of this study was to evaluate the effect of a chronic treatment with resveratrol (100mg/kg/day, i.p.), an anti-oxidant and anti-inflammatory compound on the model of treadmill-exercised mdx mice (De Luca et al., 2003). Interestingly this compound is an agonist of Sirtuin-1 (Sirt1), a NAD⁺ dependent deacetylase that activates peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α), a key modulator of muscle metabolism (Handschin et al., 2007). The antioxidant action of resveratrol is in part due to the PGC-1α-mediated increase in mitochondrial biogenesis and antioxidant scavengers (Handschin et al., 2008). The effects of resveratrol treatment were compared with those of PDN (1mg/kg/day, i.p.), the clinically used drug for DMD patients. In vivo, resveratrol counteracted the deleterious effect of exercise on mdx mouse force. In fact the increase in normalized strength over the treatment time was 2.22±0.2 in resveratrol-treated mdx mice versus 0.80±0.11 in untreated counterparts (p<0.001), with an effect higher than that of PDN treatment. An endurance test, taken as maximal distance run by each mouse until exhaustion, clearly showed that in vivo fatigability is markedly improved in resveratrol-treated mice, with a 40% increase in distance run vs. exercised counterpart, while PDN did not show any protective effect on this parameter. We also investigated the resveratrol effect on isometric contraction ex vivo and we observed that the treatment did not improve the contractile parameters in the EDL muscle, as also observed in the PDN-treated mdx mice. Interestingly, in the resveratrol-treated mice group a significant reduction of CK (by 58%) and LDH (by 80%) plasma levels was observed. These effects were greater than those observed with PDN. In addition, both treatments reduced the oxidative stress, evidenced by a 70% reduction of fibers positive to dihydroethidium (DHE), a marker of superoxide anion production, in tibialis anterior muscle. An improvement of histology profile was observed in resveratrol and PDN treated gastrocnemious muscle, with a reduction of degenerating muscle area by 30% and 60%, respectively. Resveratrol>PDN treatments increased the utrophin expression in GC muscle. In conclusion, the resveratrol treatment improved muscle performance and morphology exerting greater effects than PDN. These data support that pharmacological strategies, able to contrast oxidative stress and improve muscle metabolism, may have beneficial effects in DMD. (Supported by Charley’s Fund, USA).
 
Hoffman & Dressman (2001)Trends Pharmacol Sci22, 465–470
Bushby et al.(2007) Lancet Neurol:9(1):77-93
De Luca et al. (2003) J Pharmacol Exp Ther 304(1):453-63
Handschin et al.(2007) Genes Dev21(7):770-83
Handschin et al.(2008)Nature 454:463-9