Gold nanoparticles and diclofenac diethylammonium administered by iontophoresis reduce inflammatory cytokines expression in Achilles tendinitis

INTRODUCTION: Tendinitis affects a substantial number of people in several occupations involving repetitive work or direct trauma. Iontophoresis is a therapeutic alternative used in the treatment of injury during the inflammatory phase. In recent years, gold nanoparticles (GNP) have been studied due to their therapeutic anti-inflammatory capacity and as an alternative to the transport of several proteins. PURPOSE: This study evaluates the therapeutic effects of iontophoresis using GNPs and diclofenac diethylammonium on inflammatory parameters in rats challenged with traumatic tendinitis. METHODS: Wistar rats were divided in three treatment groups (n = 15): (1) iontophoresis + diclofenac diethylammonium; (2) iontophoresis + GNP; and (3) iontophoresis + diclofenac diethylammonium + GNP. External control was formed by challenged tendons without treatment (n = 15). Iontophoresis was administered using 0.3 mA direct current on 1.5 cm(2) electrodes. RESULTS: The levels of both inflammatory cytokines were significantly higher in untreated challenged rats, when compared with the control (5.398 ± 234 for interleukin 1 beta and 6.411 ± 432 for tumor necrosis factor alpha), which confirms the occurrence of an inflammatory stage in injury (P < 0.05). A significant decrease was observed in expression of cytokines interleukin 1 beta in the three treatment groups, in comparison with untreated challenged tendons, although, in the group treated with diclofenac and GNP, results were similar to the control (1.732 ± 239) (P < 0.05). Concerning tumor necrosis factor alpha, only the group treated with the association diclofenac and GNPs presented decreased levels, compared with the control (3.221 ± 369) (P < 0.05). CONCLUSION: The results show the efficacy of drug administration using direct current to treat tendinitis in an animal model, and the potential anti-inflammatory, carrier, and enhancing effects of GNPs in iontophoresis.