Neurobehavioral impairments from chromium exposure: Insights from a zebrafish model and drug validation

SG06, a Chalcone Derivative Targets PI3K/AKT1 Pathway for Neuroprotection and Cognitive Enhancement in an Alzheimer's Disease-Like Zebrafish Model

Alzheimer's disease (AD) and Alzheimer's dementia (ADM) are common neurodegenerative disorders marked by progressive cognitive decline, memory impairment, and behavioral deficits, which impose a significant burden on individuals and healthcare systems worldwide. Due to the complex nature of AD pathophysiology, effective treatment strategies may require targeting multiple pathways. This study explored the neuroprotective effects of the chalcone derivative SG06 in a scopolamine-induced AD-like zebrafish model using network pharmacology and molecular docking. SG06 showed strong binding to key targets such as AKT serine/threonine kinase 1 (AKT1), which are involved in processes like tau phosphorylation, amyloid-beta (Aβ) production, and inflammation. Behavioral assays indicated that SG06 improved cognitive function, reduced anxiety-like behavior, and restored social interactions. Additionally, sensory recovery was observed through better light/dark transitions and recovered olfactory function, likely due to improved neuronal communication and reduced oxidative stress. Mechanistically, SG06 appeared to activate the PI3K/AKT1 pathway, inhibiting Glycogen Synthase Kinase 3 beta (GSK3β) activity, which may help reduce tau hyperphosphorylation and amyloid processing. SG06 also restored antioxidant markers (CAT, GSH, GPx) and improved acetylcholinesterase (AChE) activity, reducing oxidative damage and cholinergic dysfunction. Histological analysis revealed improved cellular morphology and decreased Aβ plaque accumulation, while gene expression studies showed downregulation of pro-inflammatory markers and upregulation of neuroprotective genes. Additionally, SG06 helped improving neurotransmitter balance, particularly in Gamma-Aminobutyric Acid (GABA) and Dopamine (DPAN), contributing to improved synaptic plasticity and cognitive function. These findings suggest that SG06 may have potential as a multi-target therapeutic agent in addressing the complex pathology of AD.

Hydroxyl chalcone derivative DK02 as a multi-target-directed ligand for Alzheimer's disease: A preclinical study in zebrafish

BACKGROUND AND PURPOSE

Alzheimer's disease (AD) is a widespread neurodegenerative condition characterized by amyloid-beta (Aβ) plaques and tau protein aggregates, leading to significant cognitive decline. Existing treatments primarily offer symptomatic relief, underscoring the urgent need for novel therapies that address multiple AD pathways. This study evaluates the efficacy of DK02, a hydroxyl chalcone derivative, in a scopolamine-induced dementia model in zebrafish, hypothesizing that it targets several neurodegenerative mechanisms simultaneously.

EXPERIMENTAL APPROACH

We employed a blend of experiments, including in silico docking, in vitro enzyme inhibition assays and in vivo zebrafish models, to assess therapeutic effects of DK02. Methods included molecular docking to forecast interaction sites, acetylcholinesterase (AChE) inhibition testing, and various behavioural and histopathological analyses to gauge DK02's cognitive and neuroprotective impacts.

KEY RESULTS

DK02 emerged as a potent AChE inhibitor via virtual screening, and significantly enhanced cognitive functions in zebrafish, by improving memory retention and reducing anxiety-like behaviours. DK02 also displayed strong antioxidant properties, reducing oxidative stress-induced neuronal damage. Histopathological analysis confirmed its neuroprotective effects by showing decreased amyloid plaque burden and mitigated structural brain damage.

CONCLUSION AND IMPLICATIONS

DK02 shows promise as a multi-target-directed ligand for AD, offering a new therapeutic path by simultaneously addressing cholinergic, oxidative and amyloid pathways. Its potential to enhance cognitive functions and curtail neurodegeneration suggests advantages over current symptomatic treatments. Further research into DK02 mechanisms and long-term impacts is essential for its development in AD therapy.

Liquid mosquito repellent induces toxic effects in zebrafish

Mosquitoes serve as vectors for life-threatening parasitic diseases, presenting a continuous threat throughout human history. This has resulted in the extensive utilization of various mosquito repellents, including liquid mosquito repellents (LMRs), roll-ons, and topical creams. While these products demonstrate significant efficacy, the toxicological implications associated with their use are not yet fully understood and continue to be a subject of debate. The analysis conducted using gas chromatography-mass spectrometry (GC-MS) on LMR revealed the presence of 158 distinct compounds, among which were Piperazine 2,5-dimethyl propyl and a range of hydrocarbons. The analysis of network toxicology indicated that 78 of the examined compounds contravened Lipinski's rule of five and exhibited considerable overlap with target genes associated with lung cancer pathways, thereby highlighting potential concerns regarding their carcinogenic properties. The exposure of zebrafish embryos to LMR concentrations between 0.1 and 14 µg/mL resulted in developmental toxicity assays that demonstrated a dose-dependent escalation in mortality rates and the occurrence of morphological abnormalities, such as pericardial edema and skeletal deformities. Behavioral assays demonstrated a marked decrease in locomotor activity at elevated LMR concentrations, indicating potential neurotoxic effects. Biochemical analyses revealed elevated levels of reactive oxygen species (ROS), enhanced lipid peroxidation, and diminished glutathione, which are indicative of oxidative stress. Enzyme activity assays indicated a reduction in superoxide dismutase (SOD) and catalase (CAT) activities, alongside an increase in lactate dehydrogenase (LDH) activity, which suggests the occurrence of cellular damage. Analysis of gene expression demonstrated significant dysregulation in genes associated with oxidative stress (SOD1, CAT), inflammatory markers (TNF-α, IL-1β), apoptotic regulators (p53, bcl2), and neurobiological genes (brain-derived neurotrophic factor, bdnf). The results highlight the possible health hazards linked to LMR exposure, which manifest as developmental, biochemical, and genetic alterations in zebrafish embryos.

Mitigation of gentamycin induced acute kidney injury due to benzothiazole derivatives N1 and N5: Antioxidant and renoprotective mechanisms in-vivo zebrafish

Acute kidney injury (AKI) is marked by a rapid decline in renal function, often caused by oxidative stress and nephrotoxic agents. Complications limit current therapeutic strategies, and no specific drugs are available to prevent renal injury or accelerate recovery. In the present research, we investigated the therapeutic efficacy of synthesized 2-aminobenzothiazole derivatives, N1 and N5, in mitigating Gentamicin (Gen) -induced renal damage in vivo zebrafish. The preliminary work of radical scavenging and hemolysis inhibition assay revealed that, both compounds exhibited strong antioxidant and anti-inflammatory activities. Furthermore, acute toxicity assays in zebrafish embryo/larvae revealed no adverse effects at concentrations up to 200 μM were tested, highlighting the safety of these compounds. In the zebrafish AKI model, Gen exposure led to oxidative stress, inflammation, and impaired glomerular filtration with tissue damage. Treatment with N1 and N5 significantly reduced ROS levels, apoptosis, and lipid peroxidation and restored antioxidant enzyme activities. Furthermore, N5 treatment improved renal filtration and reduced proteinuria levels, indicating its ability to mitigate nephrotoxic effects. Gene expression analysis showed that N1 and N5 downregulated pro-inflammatory markers (cox-2, tnfα, mpo) and angiogenic mediators (vegf, vegfr2), demonstrating anti-inflammatory and anti-angiogenic properties. Histological analyses revealed that N1 and N5 attenuated glomerular and tubular damage, reduced necrosis, and promoted tissue repair. These findings highlight the potential of 2-aminothiazole derivatives as effective therapeutic agents for AKI, offering antioxidant, anti-inflammatory, and cytoprotective benefits and warranting further investigation into their long-term efficacy in chronic kidney disease models.

Association between the levels of toxic heavy metals and schizophrenia in the population of Guangxi, China: A case-control study

The relationship between body levels of heavy metals and the risk of schizophrenia remains unclear. This study investigates the relationship between plasma levels of toxic heavy metals and the risk of schizophrenia among adults in Guangxi, China. Plasma concentrations of lead (Pb), cadmium (Cd), arsenic (As), and chromium (Cr) were measured using inductively coupled plasma mass spectrometry (ICP-MS). To evaluate both the single and combined effects of metal exposure on the risk of schizophrenia, we employed multivariate logistic regression, Bayesian Kernel Machine Regression (BKMR), and generalized Weighted Quantile Sum (gWQS) models. Additionally, we employed the Comparative Toxicogenomics Database (CTD) to analyze the mechanistic pathways through which metal mixtures may induce schizophrenia. Relative mRNA expression levels were measured using Real-Time Quantitative Reverse Transcription Polymerase Chain Reaction (RT-qPCR). Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were conducted to predict potential biological functions. In logistic regression models, compared to the lowest exposure group (Q1), the odds ratios (ORs) for Pb in groups Q2, Q3, and Q4 were 2.18 (95% CI: 1.20-3.94), 4.74 (95% CI: 2.52-8.95), and 3.62 (95% CI: 1.80-7.28), respectively. Both BKMR and gWQS models indicated a positive correlation between the combined effects of toxic heavy metal mixtures and the risk of schizophrenia, with Pb demonstrating the most substantial impact, particularly in older adults and females. Elevated levels of tumor necrosis factor (TNF) and interleukin-1 beta (IL-1β) were observed in patients with schizophrenia, while the expression of tumor protein p53 (TP53) was significantly reduced. These findings underscore the critical need to avoid exposure to toxic heavy metals to prevent schizophrenia, highlighting significant public health implications.

1,5- diaryl pyrazole-loaded chitosan nanoparticles as COX-2 inhibitors, mitigate neoplastic growth by regulating NF-κB pathway in-vivo zebrafish model

Non-steroidal anti-inflammatory drugs (NSAIDs) have been researched for their capacity to reduce cancer incidence, primarily due to their COX-2 inhibition properties. However, concerns have arisen regarding the precision of their targeting abilities. Nanoparticle approaches are revolutionizing cancer treatment by enabling targeted drug delivery, which enhances the efficacy and reduces the toxicity of chemotherapy. Particularly, chitosan-based nanoparticles are noteworthy for their biocompatibility, biodegradability, and ability to improve drug delivery. In this study, we synthesized folic acid-conjugated, 1,5-diaryl pyrazole-loaded chitosan (FA-CS-DP) nanoparticles using the ionic gelation method. The bioavailability and anti-neoplastic effects in a 7,12-dimethylbenzanthracene (DMBA)-exposed zebrafish model was investigated. MTT assay showed dose-dependent cytotoxicity of FA-CS-DP nanoparticles against MCF-7 breast cancer. The nanoparticles showed no toxicity to zebrafish embryos up to 100 μg/mL. The nanoparticle reduced oxidative stress and enhanced apoptosis in zebrafish exposed to DMBA. The morphological examination suggests that tumor growth was prevented in the zebrafish's surface and internal regions. The gene expression analysis confirmed the decrease in the expression of anti-inflammatory genes, such as cox-2 and nf-κb, and apoptosis inhibitor genes, such as bcl-2 and mdm2. By regulating the anti-inflammatory and apoptosis inhibitor genes, FA-CS-DP nanoparticle prevents neoplastic growth in the zebrafish model.

Parental (F0) exposure to Cadmium and Ketoprofen induces developmental deformities in offspring (F1): A transgenerational toxicity assessment in zebrafish model

In the aquatic environment, the primary pollutants of heavy metals and pharmaceuticals always occur in coexisting forms, and the research about combined impacts remains unclear, especially transgenerational effects. Cadmium (Cd) is a heavy metal that can damage the endocrine reproduction systems and cause thyroid dysfunction in fish. Meanwhile, ketoprofen (KPF) is a nonsteroidal anti-inflammatory drug (NSAID) that can cause neurobehavioral damage and physiological impairment. However, to our knowledge, the combined exposure of Cd and KPF in transgenerational studies has not been reported. In this investigation, sexually mature zebrafish were subjected to isolated exposure and combined exposure to Cd (10 μg/L) and KPF (10 and 100 μg/L) at environmentally relevant concentrations for 42 days. In this background, breeding capacity, chemical accumulation rate in gonads, and tissue morphologies are investigated in parental fish. This is followed by examining the malformation rate, inflammation rate, and gene transcription in the F1 offspring. Our results indicate that combined exposure of Cd and KPF to the parental fish could increase the chemical accumulation rate and tissue damage in the gonads of fish and significantly reduce the breeding ability. Furthermore, these negative impacts were transmitted to its produced F1 embryos, reflected by hatching rate, body deformities, and thyroid axis-related gene transcription. These findings provide further insights into the harm posed by Cd in the presence of KPF to the aquatic ecosystems.

Neurobehavioral and bioaccumulative toxicity in adult in-vivo zebrafish model due to prolonged cadmium exposure in the presence of ketoprofen

Increasing industrial activity causes the release of chemical compounds into aquatic habitats, including toxic heavy metals like cadmium and medications like ketoprofen, posing considerable ecological concerns. Although previous studies have shown that cadmium and ketoprofen individually cause cognitive impairment, there is a lack of information on the combined neurological effects of the two substances. We investigated the neurological consequences of persistent cadmium exposure in the presence of ketoprofen on adult zebrafish, providing an essential model for understanding cumulative impacts on vertebrate organisms. Behavioral assessments, bioaccumulation rates, biochemical studies, and histopathological exams were conducted over 42 days in authentic environmental settings. The results of our study show that cadmium (10 µg/L) and ketoprofen (10 and 100 µg/L) at environmentally relevant concentrations had a significant impact on locomotor activity, social interactions, and cognitive responses, indicating cumulative neurotoxicity in co-exposure groups compared to single pollutant groups. Biochemical tests show disturbances in antioxidant defense systems, while histological examinations reveal structural changes in zebrafish brain regions. Ketoprofen influences cadmium accumulation in the brain, underscoring the importance of conducting complete evaluations to understand the intricate interactions between environmental pollutants. This study improves our understanding of the complex interactions between heavy metals and medications, stressing the need to consider combined exposure when assessing the neurological effects on vertebrate models.

Zebrafish models for studying cognitive enhancers

Cognitive decline is commonly seen both in normal aging and in neurodegenerative and neuropsychiatric diseases. Various experimental animal models represent a valuable tool to study brain cognitive processes and their deficits. Equally important is the search for novel drugs to treat cognitive deficits and improve cognitions. Complementing rodent and clinical findings, studies utilizing zebrafish (Danio rerio) are rapidly gaining popularity in translational cognitive research and neuroactive drug screening. Here, we discuss the value of zebrafish models and assays for screening nootropic (cognitive enhancer) drugs and the discovery of novel nootropics. We also discuss the existing challenges, and outline future directions of research in this field.

Exploring the Combined Effect of Exercise and Apigenin on Aluminium-Induced Neurotoxicity in Zebrafish

Aluminium (AL) is a strong environmental neurotoxin linked to neurodegenerative disorders. Widespread industrial use leads to its presence in water systems, causing bioaccumulation in organisms. This, in turn, results in the bioaccumulation of AL in various organisms. Several studies have highlighted the benefits of enhanced physical activity in combating neurodegenerative diseases. Meanwhile widespread presence of apigenin in aquatic environment has been largely overlooked, in terms of its potential to counter AL-induced neurotoxicity. The combined impact of exercise and apigenin in mitigating the effects of AL-induced neurotoxicity in aquatic animals remains unexplored. Hence, the objective of this study is to determine whether the combined treatment of exercise and apigenin can effectively alleviate the chronic neurotoxicity induced by AL. Zebrafish that were exposed to AL showed behaviours resembling anxiety, increased aggression, unusual swimming pattern, and memory impairment, which are typical features observed in Alzheimer's disease (AD)-like syndrome. Combined treatment of exercise and apigenin protects zebrafish from AL-induced neurotoxicity, which was measured by improvements in memory, reduced anxiety and aggression, and increased levels of antioxidant enzymes and acetylcholinesterase (AChE) activity. Furthermore, AL exposure is associated with increased expression of genes related to neuroinflammation and AD. However, synergistic effect of exercise and apigenin counteract this effect in AL-treated zebrafish. These findings suggest that AL is involved in neurodegenerative diseases in fish, which could affect the integrity of aquatic ecosystem. Hence, there is a strong correlation between enhanced physical activity, apigenin, and the well-being of the ecosystem.

Exploring the Efficacy of Pellitorine as an Antiparasitic Agent Against Argulus: Impacts on Antioxidant Levels and Immune Responses in Goldfish (Carassius auratus)

INTRODUCTION

Argulus spp. infestation is a significant challenge for aquaculture, currently, there are no approved medications available to efficiently manage this parasite. Consequently, mechanical removal of parasites using forceps and natural substances like herbs are being explored as alternative treatment methods. Pellitorine (PLE) is a naturally occurring compound found in several plant species. It is classified as an alkaloid and belongs to the class of compounds known as amides.

MATERIALS AND METHODS

This study aimed to evaluate the effectiveness of PLE in preventing Argulus spp. infestations in goldfish (Carassius auratus) and to determine the optimal dosage of PLE for the detachment of Argulus spp.

RESULTS

The findings of this study revealed that PLE enhanced the immune response of goldfish by promoting superoxide dismutase (SOD) and catalase (CAT) in Argulus-infected goldfish. Additionally, PLE induces reactive oxygen species (ROS) generation and cellular damage in the Argulus. PLE at a dosage of 5 mg/mL was able to detach 80% of the argulus from goldfish within 12 h. Therapeutic index was found to be 5.99, suggesting that PLE is the safest drug.

CONCLUSIONS

Therefore, our findings suggest that PLE can be a suitable and effective treatment option for preventing Argulus infestations in goldfish. The results of this study can guide the use of PLE at an optimal dosage to control Argulus infestation in goldfish.