Tulio de Almeida Hermes

Low-Level Laser Therapy (LLLT) in Dystrophin-Deficient Muscle Cells: Effects on Regeneration Capacity, Inflammation Response and Oxidative Stress

The present study evaluated low-level laser therapy (LLLT) effects on some physiological pathways that may lead to muscle damage or regeneration capacity in dystrophin-deficient muscle cells of mdx mice, the experimental model of Duchenne muscular dystrophy (DMD). Primary cultures of mdx skeletal muscle cells were irradiated only one time with laser and analyzed after 24 and 48 hours. The LLLT parameter used was 830 nm wavelengths at 5 J/cm² fluence. The following groups were set up: Ctrl (untreated C57BL/10 primary muscle cells), mdx (untreated mdx primary muscle cells), mdx LA 24 (mdx primary muscle cells - LLLT irradiated and analyzed after 24 h), and mdx LA 48 (mdx primary muscle cells - LLLT irradiated and analyzed after 48 h). The mdx LA 24 and mdx LA 48 groups showed significant increase in cell proliferation, higher diameter in muscle cells and decreased MyoD levels compared to the mdx group. The mdx LA 48 group showed significant increase in Myosin Heavy Chain levels compared to the untreated mdx and mdx LA 24 groups. The mdx LA 24 and mdx LA 48 groups showed significant increase in [Ca2+]i. The mdx group showed significant increase in H2O2 production and 4-HNE levels compared to the Ctrl group and LLLT treatment reduced this increase. GSH levels and GPx, GR and SOD activities increased in the mdx group. Laser treatment reduced the GSH levels and GR and SOD activities in dystrophic muscle cells. The mdx group showed significant increase in the TNF-α and NF-κB levels, which in turn was reduced by the LLLT treatment. Together, these results suggest that the laser treatment improved regenerative capacity and decreased inflammatory response and oxidative stress in dystrophic muscle cells, indicating that LLLT could be a helpful alternative therapy to be associated with other treatment for dystrophinopathies.

Beneficial cilostazol therapeutic effects in mdx dystrophic skeletal muscle.

This study evaluated the possible protective effects of cilostazol against myonecrosis in dystrophic diaphragm muscle in vivo, focusing on oxidative stress, the inflammatory response and angiogenesis. Young mdx mice, the experimental animal for Duchenne muscular dystrophy, received cilostazol for 14 days. A second group of mdx mice and a control group of C57BL/10 mice received a saline solution. In the mdx mice, cilostazol treatment was associated with reduced loss of muscle strength (−34.4%), decreased myonecrosis, reduced creatine kinase levels (−63.3%) and muscle fibres stained for immunoglobulin G in dystrophic diaphragm muscle (−81.1%), and a reduced inflammatory response, with a decreased inflammatory area (−22%), macrophage infiltration (−44.9%) and nuclear factor‐κB (−24%) and tumour necrosis factor‐α (−48%) content in dystrophic diaphragm muscle. Furthermore, cilostazol decreased oxidative stress and attenuated reactive oxygen species production (−74%) and lipid peroxidation (−17%) in dystrophic diaphragm muscle, and promoted the up‐regulation of angiogenesis, increasing the number of microvessels (15%). In conclusion, the present results show that cilostazol has beneficial effects in dystrophic muscle. More research into the potential of cilostazol as a novel therapeutic agent for the treatment of dystrophinopathies is required.

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

Chronic inflammation and oxidative stress are striking features of Duchenne muscular dystrophy disease. Diacerhein is an anthraquinone, which exhibits anti-inflammatory and antioxidant properties. Based on their actions, the present study evaluated the effects of diacerhein against myonecrosis, oxidative stress and inflammatory response in the diaphragm muscle of mdx mice and compared these results to current treatment widely used in DMD patients, with a main focus on the impact of prednisone. The results demonstrated that diacerhein treatment prevented muscle damage indicated by a decrease in the IgG uptake by muscle fibers, lower CK levels in serum, reduction of fibers with central nuclei with a concomitant increase in fibers with peripheral nuclei. It also had an effect on the inflammatory process, decreasing the inflammatory area, macrophage staining and TNF-α and IL-1β content. Regarding oxidative stress, diacerhein treatment was effective in reducing the ROS and lipid peroxidation in the diaphragm muscle from mdx mice. Compared to prednisone treatment, our findings demonstrated that diacerhein treatment improved the dystrophic phenotype in the diaphragm muscle of mdx mice similar to that of glucocorticoid therapy. In this respect, this work suggests that diacerhein has a potential use as an alternative drug in dystrophinopathy treatment and recommends that its anti-inflammatory and antioxidants properties in the dystrophic muscle should be better understood.

Sex influences diaphragm muscle response in exercised mdx mice: Diaphragm response in exercised mdx mice

Physical exercise promotes increased muscle damage in the mdx mice, the experimental model of Duchenne muscular dystrophy. Studies suggest that the estrogen level in females makes them less susceptible to muscle injuries. The aim of this study was to characterize the diaphragm (DIA) muscle response to physical exercise in male and female mdx mice. The animals were divided into four groups: female sedentary mdx; male sedentary mdx; female mdx submitted to exercise; and male mdx mice submitted to exercise. Blood samples were used to determine creatine kinase (CK). Regenerated muscle fibers were indicated by the presence of central nucleus and also inflammation areas were determined in DIA muscle sections. The alpha and beta estrogen receptors (ER) were determined by means of immunohistochemistry evaluation in the dystrophic DIA muscle. Male mdx animals submitted to exercise showed increased CK levels and inflammatory area. The quantification of regenerated fibers was higher in male animals, submitted or not to physical exercise. Greater alpha and beta ER expression was verified in the females submitted to exercise in the DIA muscle than in the other experimental groups. Therefore, estrogen may have contributed to the prevention of increased inflammatory process and DIA injury in females submitted to exercise.

Histological assessment of mdx mice treated with antioxidant supplementation

Resumen pt: Os Autores utilizaram procedimentos histopatologicos para revelar o efeito da suplementacao com os antioxidantes nacetilcisteina e deferoxamina em fibras...