Reduction of Oxidative Damage and Inflammatory Response in the Diaphragm Muscle of mdx Mice Using Iron Chelator Deferoxamine

Abstract

Oxidative stress and inflammatory processes strongly contribute to pathogenesis in Duchenne muscular dystrophy (DMD). Based on evidence that excess iron may increase oxidative stress and contribute to the inflammatory response, we investigated whether deferoxamine (DFX), a potent iron chelating agent, reduces oxidative stress and inflammation in the diaphragm (DIA) muscle of mdx mice (an experimental model of DMD). Fourteen-day-old mdx mice received daily intraperitoneal injections of DFX at a dose of 150 mg/kg body weight, diluted in saline, for 14 days. C57BL/10 and control mdx mice received daily intraperitoneal injections of saline only, for 14 days. Grip strength was evaluated as a functional measure, and blood samples were collected for biochemical assessment of muscle fiber degeneration. In addition, the DIA muscle was removed and processed for histopathology and Western blotting analysis. In mdx mice, DFX reduced muscle damage and loss of muscle strength. DFX treatment also resulted in a significant reduction of dystrophic inflammatory processes, as indicated by decreases in the inflammatory area and in NF-κB levels. DFX significantly decreased oxidative damage, as shown by lower levels of 4-hydroxynonenal and a reduction in dihydroethidium staining in the DIA muscle of mdx mice. The results of the present study suggest that DFX may be useful in therapeutic strategies to ameliorate dystrophic muscle pathology, possibly via mechanisms involving oxidative and inflammatory pathways.

Dystrophic phenotype improvement in the diaphragm muscle of mdx mice by diacerhein

“…Forelimb muscle strength was evaluated with a grip strength meter (New Primer, São Paulo, Brazil), as previously described [ 9 , 23 ]. Five measurements were obtained for each animal from each experimental group at the beginning (14 days old) and end (28 days old) of the time period.…”

“…The animals (n = 5 for each group analyzed) were anaesthetized using a mixture of ketamine hydrochloride (130 mg/kg; Francotar, Virbac, Fort Worth, TX, USA) and xylazine hydrochloride (6.8 mg/kg, 2% Virbaxil; Virbac), and blood samples (0.8 ml) were taken for biochemical assessment of muscle fiber degeneration and inflammatory cytokine, as previously described [ 9 , 23 ].…”

“…The NF-κB, TNF-α and 4-hydroxynonenal (4-HNE) content in the DIA and TA muscles of all experimental groups (n = 5 for each group analyzed) was analyzed using Western blotting, as previously reported [ 9 , 23 ]. An assay lysis buffer containing freshly added protease and phosphatase inhibitors (1% Triton, 10 mM sodium pyrophosphate, 100 mM NaF, 10 μ g/ml aprotinin, 1 mM phenylmethanesulphonyl fluoride and 0.25 mM Na 3 VO 4 ) was used to lyse the muscles.…”

Beneficial cilostazol therapeutic effects in mdx dystrophic skeletal muscle

“…Forelimb muscle strength was evaluated with a grip strength meter (New Primer, São Paulo, Brazil), as previously described. 25,26 In brief, five measurements were obtained for each animal at the beginning (14 days old) and end (28 days old) of cilostazol treatment. Absolute strength was normalized to body weight at 14 and 28 days.…”

N-acetylcysteine Decreases Fibrosis and Increases Force-Generating Capacity of mdx Diaphragm

“…Inflammatory markers such as immune cell infiltration and cytokine concentrations are increased in mdx diaphragm, as well as the abundance of collagen deposits [17]. Moreover, indices of oxidative stress including lipid peroxidation and superoxide levels are elevated in mdx diaphragm compared with control muscle [18]. Inflammation and high levels of reactive oxygen species (ROS) can culminate in skeletal muscle damage leading to poor physiological performance [19].…”