Therapeutic effects of iontophoresis with gold nanoparticles in the repair of traumatic muscle injury.

Studies have shown the benefits of gold nanoparticles (GNPs) in muscle and epithelial injury models. In physiotherapy, the use of the microcurrent apparatus is associated with certain drugs (Iontophoresis) to increase the topical penetration and to associate the effects of both therapies. Therefore, the objective of this study was to investigate the effects of iontophoresis along with GNPs in the skeletal muscle of rats exposed to a traumatic muscle injury. We utilised 50 Wistar rats randomly divided in to five experimental groups (n = 10): Control group (CG); Muscle injury group (MI); MI + GNPs (20 nm, 30 mg kg-1); MI + Microcurrent (300 μA); and MI + Microcurrent + GNPs. The treatment was performed daily for 7 days, with the first session starting at 24 h after the muscle injury. The animals were sacrificed and the gastrocnemius muscle was surgically removedand stored for the proper evaluations. The group that received iontophoresis with GNPs showed significant differences in inflammation and oxidative stress parameters and in the histopathological evaluation showed preserved morphology. In addition, we observed an improvement in the locomotor response and pain symptoms of these animals. These results suggest that the association of boththerapies accelerates the inflammatory response of the injured limb.