Effects of Aluminum Oxide Nanoparticles in the Cerebrum, Hippocampus, and Cerebellum of Male Wistar Rats and Potential Ameliorative Role of Melatonin

Ameliorating and Therapeutic Impact of Curcumin Nanoparticles Against Aluminum Oxide Nanoparticles Induced Kidney Toxicity, DNA Damage, Oxidative Stress, PCNA and TNFα Alteration in Male Rats

Aluminum oxide nanoparticles (Al2O3 NPs) are among the most extensively utilized nanoparticles in nanotechnology and that have negative impacts on the environment. Therefore, the intention of this work is to investigate the protective and therapeutic effects of curcumin in nanoform (Cur NPs) against Al2O3 NPs induced kidney toxicity, oxidative stress, DNA damage, and changes in necrosis factor alpha (TNFα) and proliferating cell nuclear antigen (PCNA) expressions in male rats. Fifty healthy adult male were divided into five groups [G1, control; G2, received 50 mg/kg/day for 4 weeks of Cur NPs orally; G3, received 6 mg/kg BW orally for 4 weeks of Al2O3 NPs; G4, (Cur NPs + Al2O3 NPs) received Cur NPs and Al2O3 NPs at a dose similar to G2 and G3, respectively for 4 weeks; G5, (Al2O3 NPs + Cur NPs) received Al2O3 NPs at a dose similar to G3 for 4 weeks then received Cur NPs at a dose similar to G2 for another 4 weeks]. Current results revealed that Al2O3 NPs induced a significant elevation in serum urea, creatinine, chloride, calcium, kidney malondialdehyde (MDA), DNA damage, injury, TNFα and PCNA expressions and a significant depletion in serum potassium, kidney superoxide dismutase (SOD), glutathione (GSH) as compared to control. On the other hand, treatments of Al2O3 NPs with Cur NPs induced modulation in all altered parameters and improved kidney functions and structure, with best results for the Al2O3 NPs + Cur NPs than Cur NPs + Al2O3 NPs. In conclusion, Cur NPs has the capacity to mitigate the renal toxicity induced by Al2O3 NPs in male albino rats.

Naringenin mitigates nanoparticulate-aluminium induced neuronal degeneration in brain cortex and hippocampus through downregulation of oxidative stress and neuroinflammation

Alumunium usage and toxicity has been a global concern especially an increased use of nanoparticulated aluminum (Al-NPs) products from the environment and the workplace. Al degrades in to nanoparticulate form in the environment due to the routine process of bioremediation in human body. Al-NPs toxicity plays key role in the pathophysiology of neurodegeneration which is characterised by the development of neurofibrillary tangles and neuritic plaques which correlates to the Alzheimer's disease. This study evaluated the Al-NPs induced neurodegeneration and causative behavioral alterations due to oxidative stress, inflammation, DNA damage, β-amyloid aggregation, and histopathological changes in mice. Furthermore, the preventive effect of naringenin (NAR) as a potent neuroprotective flavonoid against Al-NPs induced neurodegeneration was assessed. Al-NPs were synthesized and examined using FTIR, XRD, TEM, and particle size analyzer. Mice were orally administered with Al-NPs (6 mg/kg b.w.) followed by NAR treatment (10 mg/kg b.w. per day) for 66 days. The spatial working memory was determined by novel object recognition, T-maze, Y-maze, and Morris Water Maze tests. We measured nitric oxide, advanced oxidation of protein products, protein carbonylation, lipid peroxidation, superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, reduced glutathione, oxidised glutathione, and acetylcholine esterase, as well as cytokines analysis, immunohistochemistry, and DNA damage. Al-NPs significantly reduced the learning memory power, increased oxidative stress, reduced antioxidant enzymatic activity, increased DNA damage, altered the levels of cytokines, and increased β-amyloid aggregation in the cortex and hippocampus regions of the mice brain. These neurobehavioral impairments, neuronal oxidative stress, and histopathological alterations were significantly attenuated by NAR supplementation. In conclusion, Al-NPs may be potent neurotoxic upon exposure and that NAR could serve as a potential preventive measure in the treatment and management of neuronal degeneration.

Protective Role of Melatonin Against Abamectin-Induced Biochemical, Immunohistochemical, and Ultrastructural Alterations in the Testicular Tissues of Rats

Abamectin is one of the most widely used pesticides due to its strong insecticidal and anthelmintic activities. Melatonin is a neurohormone with potent antioxidant, anti-apoptotic, and anti-inflammatory effects. This study aimed to investigate the potential ameliorative effects of melatonin against abamectin-induced testicular toxicity in rats. Twenty-four rats were divided into four groups: control group (1 mL/kg/day corn oil), melatonin-treated group (10 mg/kg/day), abamectin-treated group (0.5 mg/kg/day), and melatonin plus abamectin-treated group. Test substances were administered via oral gavage once daily for 28 days. While MDA and 8-OHdG levels increased in the testicular tissue of rats treated with abamectin, SOD, CAT, GPx, and GST enzyme activities decreased significantly. While interleukin-17 levels, TNF-α, and caspase3 expression increased in the testicular tissue, acetylcholinesterase activity decreased. At the same time, serum gonadotropins (luteinizing and follicle-stimulating hormones) and testosterone levels decreased. Light microscope examinations of testicular tissues revealed severe histopathological changes, such as atrophic hyalinized seminiferous tubules, basement membrane irregularity, degeneration, spermatogenic cell loss, and necrosis. Electron microscopy examinations revealed large vacuoles in Sertoli and spermatogenic cells, swelling and vacuolization in mitochondria, lysosomal structures, and increased pyknotic nuclei. In contrast, melatonin supplementation significantly ameliorated abamectin-induced testicular toxicity in rats through antioxidant, antiapoptotic, and anti-inflammatory mechanisms.

Melatonin intervention to prevent nanomaterial exposure-induced damages: A systematic review and meta-analysis of in vitro and in vivo studies

Given its antioxidant, anti-inflammatory, and antiapoptotic properties, melatonin (MEL), a health-caring food to improve sleep disorders, is hypothesized to protect against nanomaterial exposure-induced toxicity. However, the conclusion derived from different studies seemed inconsistent. A meta-analysis of all available preclinical studies was performed to examine the effects of MEL on nanomaterial-induced damages. Eighteen relevant studies were retrieved through searching five electronic databases up to December 2023. The meta-analysis showed that relative to control, MEL treatment significantly increased cell viability (standardized mean difference [SMD = 1.27]) and alleviated liver function (lowered AST [SMD = -3.89] and ALT [SMD = -5.89]), bone formation (enhanced BV/TV [SMD = 4.13] and lessened eroded bone surface [SMD = -5.40]), and brain nerve (inhibition of AChE activity [SMD = -3.60]) damages in animals. The protective mechanisms of MEL against damages caused by nanomaterial exposure were associated with its antiapoptotic (decreased Bax/Bcl-2 ratio [SMD = -4.50] and caspase-3 levels [dose <100 μM: SMD = -3.66]), antioxidant (decreased MDA [in vitro: SMD = -2.84; in vivo: SMD = -4.27]), and anti-inflammatory (downregulated TNF-α [in vitro: SMD = -5.41; in vivo: SMD = -3.21] and IL-6 [in vitro: SMD = -5.90; in vivo: SMD = -2.81]) capabilities. In conclusion, our study suggests that MEL should be supplemented to prevent damages in populations exposed to nanomaterials.

Neuroprotective Assessment of Betaine against Copper Oxide Nanoparticle-Induced Neurotoxicity in the Brains of Albino Rats: A Histopathological, Neurochemical, and Molecular Investigation

Copper oxide nanoparticles (CuO-NPs) are commonly used metal oxides. Betaine possesses antioxidant and neuroprotective activities. The current study aimed to investigate the neurotoxic effect of CuO-NPs on rats and the capability of betaine to mitigate neurotoxicity. Forty rats; 4 groups: group I a control, group II intraperitoneally CuO-NPs (0.5 mg/kg/day), group III orally betaine (250 mg/kg/day) and CuO-NPs, group IV orally betaine for 28 days. Rats were subjected to neurobehavioral assessments. Brain samples were processed for biochemical, molecular, histopathological, and immunohistochemical analyses. Behavioral performance of betaine demonstrated increasing locomotion and cognitive abilities. Group II exhibited significantly elevated malondialdehyde (MDA), overexpression of interleukin-1 beta (IL-1β), and tumor necrosis factor-alpha (TNF-α). Significant decrease in glutathione (GSH), and downregulation of acetylcholine esterase (AChE), nuclear factor erythroid 2-like protein 2 (Nrf-2), and superoxide dismutase (SOD). Histopathological alterations; neuronal degeneration, pericellular spaces, and neuropillar vacuolation. Immunohistochemically, an intense immunoreactivity is observed against IL-1β and glial fibrillary acidic protein (GFAP). Betaine partially neuroprotected against CuO-NPs associated alterations. A significant decrease at MDA, downregulation of IL-1β, and TNF-α, a significant increase at GSH, and upregulation of AChE, Nrf-2, and SOD. Histopathological alterations partially ameliorated. Immunohistochemical intensity of IL-1β and GFAP reduced. It is concluded that betaine neuroprotected against most of CuO-NP neurotoxic effects through antioxidant and cell redox system stimulating efficacy.

Environmental aluminum oxide inducing neurodegeneration in human neurovascular unit with immunity

Aluminum oxide nanoparticle (AlNP), a ubiquitous neurotoxin highly enriched in air pollution, is often produced as an inevitable byproduct in the manufacturing of industrial products such as cosmetics and metal materials. Meanwhile, ALNP has emerged as a significant public health concern due to its potential association with neurological diseases. However, the studies about the neurotoxic effects of AlNP are limited, partially due to the lack of physiologically relevant human neurovascular unit with innate immunity (hNVUI). Here, we employed our AlNP-treated hNVUI model to investigate the underlying mechanism of AlNP-driven neurodegeneration. First, we validated the penetration of AlNP across a blood-brain barrier (BBB) compartment and found AlNP-derived endothelial cellular senescence through the p16 and p53/p21 pathways. Our study showed that BBB-penetrating AlNP promoted reactive astrocytes, which produced a significant level of reactive oxygen species (ROS). The astrocytic neurotoxic factors caused neuronal damage, including the synaptic impairment, the accumulation of phosphoric-tau proteins, and even neuronal death. Our study suggests that AlNP could be a potential environmental risk factor of neurological disorders mediated by neuroinflammation.