Gold Nanoparticle-Based Therapy for Muscle Inflammation and Oxidative Stress

Anti-inflammatory role of gold nanoparticles in the prevention and treatment of Alzheimer's disease

Alzheimer's disease (AD) is a neurodegenerative disease that causes memory and cognitive dysfunction and reduces a person's decision-making and reasoning functions. AD is the leading cause of dementia in the elderly. Patients with AD have increased expression of pro-inflammatory cytokines in the nervous system, and the sustained inflammatory response impairs neuronal function. Meanwhile, long-term use of anti-inflammatory drugs can reduce the incidence of AD to some extent. This confirms that anti-neuroinflammation may be an effective treatment for AD. Gold nanoparticles (AuNPs) are an emerging nanomaterial with promising physicochemical properties, anti-inflammatory and antioxidant. AuNPs reduce neuroinflammation by inducing macrophage polarization toward the M2 phenotype, reducing pro-inflammatory cytokine expression, blocking leukocyte adhesion, and decreasing oxidative stress. Therefore, AuNPs are gradually attracting the interest of scholars and are used for treating inflammatory diseases and drug delivery. Herein, we explored the role and mechanism of AuNPs in treating neuroinflammation in AD. The use of AuNPs for treating AD is a topic worth exploring in the future, not only to help solve a global public health problem but also to provide a reference for treating other neuroinflammatory diseases.

Gold nanoparticles retrogradely penetrate through testicular barriers via Sertoli-cells mediated endocytosis/exocytosis and induce immune response in mouse

Despite the rapidly growing interest in nanoparticle-mediated controllable male contraception and recovery of male fertility, novel applications of nanoparticles in these processes are limited by a knowledge gap regarding their transport and distribution in the testes. Here, we investigated the fate of gold nanoparticles in the mouse testes using two injection methods, namely, interstitial testicular injection (IT-AuNPs, AuNPs exposure in the interstitial compartment of the testes) and rete testis injection (RT-AuNPs, AuNPs exposure in the adluminal compartment of the seminiferous tubules). In this study, we used 100 nm spherical AuNPs and microinjected with 5 μL AuNPs (30 mg/mL) for the experiments. For IT-AuNP injection, we found that AuNPs could not penetrate through the Sertoli cell-mediated blood-testis barrier (BTB) of the seminiferous tubules, and no male reproductive toxicity was observed. For RT-AuNP injection, AuNPs could be retrogradely transported from the adluminal compartment to the interstitial compartment of the testes via Sertoli cell-mediated endocytosis/exocytosis, resulting in damage and the release of inflammatory cytokines in the mouse testis. Our results highlight a retrograde nanoparticle transport function of Sertoli cells, thereby providing a mechanistic overview of the development and use of nanobiotechnology in male reproduction. SYNOPSIS: This study provides new insights into male reproductive immunotoxicity for AuNPs exposure and elucidates a mechanism via Sertoli cell-mediated endocytosis/exocytosis.

Green synthesis of gold nanoparticles modulates lipopolysaccharide-induced lung inflammation in Wistar rats

This study aimed to investigate the effect of intranasal treatment of gold nanoparticles (GNPs) and Curcumin (Cur) on the lipopolysaccharide (LPS)-induced acute pulmonary inflammatory response. A single intraperitoneal injection of LPS (0.5 mg/Kg) was performed, and the animals in the Sham group were injected with 0.9% saline. Treatment was daily intranasally with GNPs (2.5 mg/L), Cur (10 mg/kg) and GNP-Cur started 12 h after LPS administration and ended on the seventh day. The results show that the treatment performed with GNP-Cur was the most effective to attenuate the action of pro-inflammatory cytokines, and a lower leukocyte count in the bronchoalveolar lavage, in addition to positively regulating anti-inflammatory cytokines in relation to other groups. As a result, it promoted an oxirreductive balanced environment in the lung tissue, providing a histological outcome with a reduction in inflammatory cells and greater alveolar area. The group treated with GNPs-Cur was superior to the other groups, with better anti-inflammatory activity and reduced oxidative stress, resulting in less morphological damage to lung tissue. In conclusion, the use of reduced GNPs with curcumin demonstrates promising effects in the control of the acute inflammatory response, helping to protect the lung tissue at the biochemical and morphological levels.

Microcurrent and Gold Nanoparticles Combined with Hyaluronic Acid Accelerates Wound Healing

This study aimed to investigate the effects of iontophoresis and hyaluronic acid (HA) combined with a gold nanoparticle (GNP) solution in an excisional wound model. Fifty Wistar rats (n = 10/group) were randomly assigned to the following groups: excisional wound (EW); EW + MC; EW + MC + HA; EW + MC + GNPs; and EW + MC + HA + GNPs. The animals were induced to a circular excision, and treatment started 24 h after injury with microcurrents (300 µA) containing gel with HA (0.9%) and/or GNPs (30 mg/L) in the electrodes (1 mL) for 7 days. The animals were euthanized 12 h after the last treatment application. The results demonstrate a reduction in the levels of pro-inflammatory cytokines (IFNϒ, IL-1β, TNFα, and IL-6) in the group in which the therapies were combined, and they show increased levels of anti-inflammatory cytokines (IL-4 and IL-10) and growth factors (FGF and TGF-β) in the EW + MC + HA and EW + MC + HA + GNPs groups. As for the levels of dichlorofluorescein (DCF) and nitrite, as well as oxidative damage (carbonyl and sulfhydryl), they decreased in the combined therapy group when compared to the control group. Regarding antioxidant defense, there was an increase in glutathione (GSH) and a decrease in superoxide dismutase (SOD) in the combined therapy group. A histological analysis showed reduced inflammatory infiltrate in the MC-treated groups and in the combination therapy group. There was an increase in the wound contraction rate in all treated groups when compared to the control group, proving that the proposed therapies are effective in the epithelial healing process. The results of this study demonstrate that the therapies in combination favor the tissue repair process more significantly than the therapies in isolation.

Neuroprotective Effect of Gold Nanoparticles and Alpha-Lipoic Acid Mixture against Radiation-Induced Brain Damage in Rats

The current study aims to evaluate the possible neuroprotective impact of gold nanoparticles (AuNPs) and an alpha-lipoic acid (ALA) mixture against brain damage in irradiated rats. AuNPs were synthesized and characterized using different techniques. Then, a preliminary investigation was carried out to determine the neuroprotective dose of AuNPs, where three single doses (500, 1000, and 1500 µg/kg) were orally administrated to male Wistar rats, one hour before being exposed to a single dose of 7Gy gamma radiation. One day following irradiation, the estimation of oxidative stress biomarkers (malondialdehyde, MDA; glutathione peroxidase, GPX), DNA fragmentation, and histopathological alterations were performed in brain cortical and hippocampal tissues in both normal and irradiated rats. The chosen neuroprotective dose of AuNPs (1000 µg/kg) was processed with ALA (100 mg/kg) to prepare the AuNPs-ALA mixture. The acute neuroprotective effect of AuNPs-ALA in irradiated rats was determined against valproic acid as a neuroprotective centrally acting reference drug. All drugs were orally administered one hour before the 7Gy-gamma irradiation. One day following irradiation, animals were sacrificed and exposed to examinations such as those of the preliminary experiment. Administration of AuNPs, ALA, and AuNPs-ALA mixture before irradiation significantly attenuated the radiation-induced oxidative stress through amelioration of MDA content and GPX activity along with alleviating DNA fragmentation and histopathological changes in both cortical and hippocampal tissues. Notably, the AuNPs-ALA mixture showed superior effect compared to that of AuNPs or ALA alone, as it mitigated oxidative stress, DNA damage, and histopathological injury collectively. Administration of AuNPs-ALA resulted in normalized MDA content, increased GPX activity, restored DNA content in the cortex and hippocampus besides only mild histopathological changes. The present data suggest that the AuNPs-ALA mixture may be considered a potential candidate for alleviating radiation-associated brain toxicity.