This study is a preclinical evaluation of the effect of a combined treatment of α-methyl-prednisolone (PDN) with taurine, a safe aminoacid with positive effects on some pathology-related events. Methods: PDN (1 mg/kg/day i.p.) and taurine (1 g/kg/day orally) were administered either alone or in combination, for 4–8 weeks to male dystrophic mdx mice chronically

exercised on a treadmill. Effects were assessed in vivo and ex vivo with a variety of methodological approaches. Results:In vivo, each treatment significantly signaling pathway increased fore limb strength, a marked synergistic effect being observed with the combination PDN + taurine. Ex vivo, PDN + taurine completely restored the mechanical threshold, an electrophysiological

index of calcium homeostasis, of extensor digitorum longus myofibres and the benefit was greater than for PDN alone. In parallel, the overactivity of voltage-independent cation channels in dystrophic myofibres was reduced. No effects were observed on plasma levels of creatine kinase, while find more lactate dehydrogenase was decreased by taurine and, to a minor extent, by PDN + taurine. A similar histology profile was observed in PDN and PDN + taurine-treated muscles. PDN + taurine significantly increased taurine level in fast-twitch muscle and brain, by high-pressure liquid chromatography analysis. Conclusions: The combination PDN + taurine

has additive actions on in vivo and ex vivo functional end points, with less evident advantages on histopathology and biochemical markers of the disease. X-chromosome gene mutations resulting in the absence of the protein dystrophin cause the severe Duchenne muscular Idelalisib in vitro dystrophy (DMD) in humans and dystrophic conditions in animals, such as the mdx mouse [1,2], characterized by progressive muscle weakness and wasting. Dystrophin is a subsarcolemmal component of a multimolecular network (the dystrophin–glycoprotein complex) that ensures a physical linkage between the intracellular cytoskeleton and the extracellular matrix, providing mechanical stability to myofibres during contraction [1]. The absence of dystrophin triggers a complex and still unclear sequence of events that finally lead to progressive myofibre degeneration, failing regeneration and fibrosis. Dystrophin-deficient myofibres show changes in calcium homeostasis, mainly sustained by the increased sarcolemmal influx of calcium ions through voltage-insensitive calcium channels [3–7]. Such changes contribute to modification in excitation-contraction coupling as well as to degeneration through the activation of proteolytic enzymes and/or apoptotic pathways [8–11]. There is also evidence of an early and self-sustained inflammatory response contributing to muscle degeneration and late fibrosis [12–16].