Avaliação do perfil citotóxico e potencial anti-inflamatório de nanopartículas de ouro

Abstract

Gold compounds already demonstrated anti-inflammatory properties in previous studies, in addition to important antioxidant potential. The use of gold in nanoparticle form is promising for the treatment of inflammatory conditions such as periodontal disease, especially for its mechanism of action. Although the established gold biocompatibility, it is important to pay attention to the possible toxic effect of gold on nanoparticulate form, for its ease of penetration through the tissues and membranes, mainly in response to its size and gold concentration. The study purpose was the physical characterization of gold nanoparticles (AuNPs) of 10, 20 and 30 nm used in the experiments, in addition to test their topical effect in models of acute inflammation in vivo (ear edema TPA-induced and paw edema LPS-induced) and verify its cytotoxicity in fibroblasts and macrophages mice cell cultures after 12, 24 e 48 hours by MTT and Neutral Red assay and exclusion of trypan blue test. To characterize the AuNPs were performed the ultraviolet-visible spectroscopy, x-ray diffraction, atomic absorbance, zeta potential and Field Emission Gun Scanning Electron Microscopy (FEG). The characterization tests results shown that the nanoparticles are stable and truly presented the diameters of 10, 20 and 30 nm, as proposed by synthesis method, and so are suitable for use in subsequent experiments. In the ear edema TPA-induced model AuNPs cream formulation at 0.1% reduced edema formation at 47.76%, while the cream formulation at 0.06% reduced 33.72% of edema after 6 hours. After 24 hours all formulations tested showed a reduction of edema formation, presenting results with no statistical difference compared to the group treated with dexamethasone. In LPS-induced paw edema model the AuNPs cream formulation at 0.1% was able to reduce edema formation in 84.46% and cream formulation at 0.6% decreased 86.57%, also without showing statistical difference compared to the group treated with dexamethasone. In viability tests, the MTT and Neutral Red methods were not able to obtain reliable results, but exclusion trypan blue test indicated no cytotoxicity of AuNPs after 12h in fibroblasts and macrophages cell cultures. After 24h incubation, the dispersions of AuNPs in 3 diameters at the highest concentration (35 mg/L) reduced the macrophages viability and fibroblast viability decreased with most of the tested AuNPs dispersions. After 48h all tested AuNPs dispersions concentrations and diameters were able to reduce the percentages of fibroblasts and macrophages cell viability.