Methylchloroisothiazolinone (CMIT) and polyhexamethylene guanidine (PHMG) are antimicrobial biocides associated with pulmonary toxicity, although their comparative cellular stress mechanisms remain unclear. Here, we investigated how CMIT and PHMG differentially alter the proteome of human alveolar epithelial A549 cells under subcytotoxic conditions. Cells were exposed to CMIT or PHMG, and global proteomic profiling was performed using label-free liquid chromatography-tandem mass spectrometry. Differentially expressed proteins (DEPs) were identified at a 1% false discovery rate with an absolute log2 fold change ≥1. Functional analyses were conducted using Gene Ontology, Kyoto Encyclopedia of Genes and Genomes, and Ingenuity Pathway Analysis, and selected proteins were validated by western blotting. Comparative toxicoproteomics revealed distinct stress-response signatures induced by the two biocides. CMIT preferentially altered proteins associated with proteostasis, oxidative stress, and protein quality control, whereas PHMG was characterized by coordinated depletion of ribosome-associated and translation-related proteins. A total of 73 and 155 DEPs were identified in CMIT- and PHMG-treated cells, respectively, with 22 proteins shared between treatments. Western blotting confirmed PSMD3, TUBB2A, and GLRX1 as CMIT-responsive proteins and THRAP3, DHX15, and RPL4 as PHMG-responsive markers. These findings provide comparative mechanistic insight into how CMIT and PHMG induce distinct epithelial stress responses and identify candidate protein markers that may support future in vitro assessment of biocide-induced pulmonary toxicity.
Silica nanoparticles (SiO₂NPs) are increasingly used in biomedical and industrial applications, yet their effects on endothelial cell metabolism at the pathway level remain incompletely characterized. Here, we used 1H NMR-based metabolomics to investigate the metabolic response of human endothelial cells (HUV-EC-C) exposed to prolate SiO₂NP@biomolecule agglomerates formed spontaneously in serum-containing medium across a range of concentrations and incubation times. Exposure induced dose- and time-dependent metabolic reprogramming, characterized by increased glucose consumption and a metabolic profile consistent with increased glycolytic reliance, together with extracellular accumulation of succinate and glycolytic end-products consistent with alterations in TCA cycle-associated metabolism. Depletion of NADP+ and glutathione precursors, together with increased extracellular pyroglutamate, indicated alterations in redox-related metabolism and glutathione turnover, which were further supported by changes in intracellular reactive oxygen species levels. Additionally, reductions in phosphocholine-related metabolites and UDP-GlcNAc indicated alterations in phospholipid metabolism and protein glycosylation, while creatine-phosphocreatine depletion was consistent with impaired energy homeostasis. These metabolic alterations were accompanied by fluorescence microscopy evidence of cytoskeletal disorganization, cell shrinkage, and apoptotic-like features. Collectively, our findings identify dose- and time-dependent metabolic reprogramming in endothelial cells exposed to SiO₂NP@biomolecule agglomerates and support a working model involving alterations in glycolytic reliance, mitochondrial-associated metabolism, redox regulation, energy homeostasis, and membrane remodeling. Given that these mechanistic interpretations are primarily based on metabolomic profiles and complementary ROS measurements, further functional studies are required to establish the underlying metabolic pathways. These findings provide a metabolic framework for understanding endothelial responses to biologically transformed SiO₂NPs and their potential relevance to nanoparticle-induced vascular dysfunction.
The monocarboxylate transporter 8 (MCT8) transports thyroid hormone (TH) across cell membranes, and plays a critical role in transporting TH across the blood brain barrier. The importance of MCT8 for TH regulation demonstrated by the congenital neurological and physical impairment that occurs in individuals with a nonfunctional MCT8 protein. Chemical inhibition of MCT8 may disrupt thyroid signaling. Previous described assay of MCT8-mediated triiodothyronine (T3) uptake relied on iodide release following high-temperature ammonium persulfate (APS) digestion which may be compromised by evaporation and degradation of plasticware. We evaluated a UV-assisted APS digestion as an alternative to heating. Using a commercial UV lamp, digestion efficiency and assay performance were compared for UV or heat-mediated MCT8 assay. UV for 40 min was comparable to heat digestion and yielded equivalent Z' factors, IC₅₀ values, and dose-response curves. Longer exposure did not improve assay performance but caused plate discoloration. The assay using UV digestion for 40 min produced results comparable to those obtained with heat digestion for known MCT8 inhibitors bromosulfophthalein (BSP) and silychristin (SC). Additional reference chemicals showed consistent results between UV digestion for 40 min and heating at 90 °C for 60 min. In summary, UV-assisted APS digestion is a reliable, faster, and lower-temperature alternative to heat digestion for screening of chemicals that may disrupt MCT8-mediated TH transport.
Trastuzumab resistance remains a major clinical barrier in the treatment of HER2-positive breast cancer. To identify therapeutic candidates capable of overcoming resistance, we established trastuzumab-resistant derivatives of SKBR3 and BT474 cells and performed a high-throughput screen of a modified ChemDiv Natural Product-Based Library. Myricetin emerged as a top hit with selective anti-survival activity against resistant cells while sparing normal breast epithelial cells. Mechanistic studies revealed that myricetin selectively suppressed mitochondrial complex I activity without affecting complex II and III function, leading to marked reductions in basal and maximal respiration, diminished oxidative phosphorylation capacity, and significant depletion of intracellular ATP and induction of oxidative stress. Mitochondrial respiration-deficient ρ0 cells were less sensitive to myricetin, confirming that its cytotoxicity is at least partly mitochondria-dependent. In vivo, myricetin significantly inhibited the growth of trastuzumab-resistant xenograft tumors and reduced mitochondrial respiratory activity in freshly excised tumor tissues. Myricetin was well tolerated, with stable body weight, normal serum-biochemical parameters, and no detectable systemic toxicity. Importantly, myricetin treatment significantly prolonged survival in resistant xenograft-bearing mice. Collectively, these findings identify myricetin as a promising mitochondrial-targeting compound capable of overcoming trastuzumab resistance in HER2+ breast cancer and support its further development as a therapeutic candidate.
Ocimum sanctum (OS) encompasses a spectrum of bioactive secondary metabolites, including flavonoids and phenolic compounds, which have demonstrated potential therapeutic effects in neurological and cardiovascular disorders. The present investigation explored the neuroprotective ability of methanolic (OSM) and ethanolic (OSE) extracts of OS leaves against rotenone-induced cytotoxicity and oxidative stress in SH-SY5Y human neuroblastoma cells, an established in vitro model of Parkinson's disease (PD). Cells were pre-treated with OSM or OSE (100 μg/mL) extracts prior to rotenone exposure, and neuroprotective efficacy was evaluated. Results showed that rotenone significantly reduced cell viability, increased intracellular and mitochondrial reactive oxygen species (ROS) generation, disrupted mitochondrial membrane potential, decreased the expression of PD-associated marker proteins (Parkin, DJ-1, BDNF, and tyrosine hydroxylase) and promoted α-synuclein aggregation. Pre-treatment with both OSM and OSE extracts significantly attenuated these pathological changes, with OSE extract consistently exhibiting greater neuroprotective efficacy than OSM extract. The findings demonstrate that OS, particularly its OSE extract, protects neuronal cells by reducing oxidative stress, preserving mitochondrial function, restoring PD-associated protein expression, and suppressing α-synuclein aggregation. These results highlight the therapeutic potential of OS as a promising neuroprotective candidate for mitigating mitochondrial dysfunction associated with PD.
Etoposide (ETO) is an anticancer drug that inhibits topoisomerase II but also causes cellular senescence. 7,8-Dihydroxyflavone (7,8-DHF), a small-molecule tropomyosin receptor kinase B agonist, has demonstrated cardioprotective effects in multiple injury models; however, its ability to prevent DNA damage in cardiomyocytes remains unclear. We therefore examined whether 7,8-DHF protects H9c2 cardiomyocytes from ETO-induced genotoxicity and investigated the underlying mechanisms. Short-term (2 h) ETO exposure induced a concentration-dependent increase in the DNA damage marker γ-H2AX without immediate cytotoxicity. 7,8-DHF pretreatment significantly attenuated this early DNA damage and blunted acute p53 upregulation. Nutlin-3a, a p53 agonist, abolished the protective effect of 7,8-DHF against early DNA damage. In contrast, prolonged (24 h) ETO exposure induced marked cytotoxicity, as evidenced by increased apoptosis, elevated lactate dehydrogenase (LDH) release, and sustained γ-H2AX elevation. 7,8-DHF significantly preserved cell morphology, reduced LDH release, and decreased apoptosis. Mechanistically, while ETO alone upregulated p53, co-treatment with 7,8-DHF further enhanced p53 expression after prolonged exposure, and p53 knockdown reversed the cardioprotective effect of 7,8-DHF, indicating a p53-dependent mechanism under chronic insult. In summary, 7,8-DHF mitigates ETO-induced DNA damage and cytotoxicity in cardiomyocytes through time-dependent, biphasic modulation of the p53 pathway, highlighting its potential as an adjuvant cardioprotective strategy during genotoxic chemotherapy.
Oral carcinoma is an aggressive cancer characterized by significant morbidity and limited treatment alternatives due to drug resistance and systemic toxicity. The study investigates phytol (PYT), for its unexplored anticancer efficacy against oral epidermal carcinoma (KB) cells. The objective was to enhance the limitations associated with the inadequate solubility and bioavailability of PYT via polyethylene glycol (PEG) encapsulation (PYT @PEG), and to establish its molecular mechanism through in vitro and in silico methodologies. In vitro assays showed that PEG encapsulation improves the therapeutic efficacy of PYT by enhancing its bioavailability and cellular uptake, leading to increased cytotoxic activity, generate higher levels of reactive oxygen species (ROS), depolarize the mitochondria, trigger apoptosis, and interrupt the cell cycle at the G0/G1 stage. Molecular docking showed that PYT binds effectively to CDK4 (-9.8 kcal/mol) because of hydrophobic and polar interactions with Val 96, Glu 144, and Asp 99. Molecular dynamics simulations validated complex stability, exhibiting RMSD values between 2.0 and 2.6 Å and RMSF ≤1.4 Å, thereby indicating a stable interaction. The study demonstrated that encapsulating PYT with PEG mitigates its poor solubility and low bioavailability, thus establishing PYT@PEG as a promising natural therapeutic candidate, with computational analyses suggesting CDK4 as a potential molecular target associated with its antiproliferative activity in oral carcinoma.
Animal-based toxicity testing is limited in throughput and mechanistic characterization, underscoring the need for cell-based approaches. Incorporating molecular readouts, such as lipidomics, can enhance the translational relevance of cell-based assays. Because untargeted lipidomic analyses are time-consuming and can require large sample volumes, a targeted workflow was used in this study to characterize drug-induced liver injury-related lipid responses in primary hepatocytes from multiple species. Multiple reaction monitoring was applied in a targeted lipidomics workflow by coupling liquid-chromatography with triple quadrupole mass spectrometry (LC-MS/MS) for 148 lipid targets across 3 categories and 11 classes. We used primary hepatocytes from human, rat, monkey, and dog cultured in 96-well plates and exposed to chlorpromazine (1-30 μM), bosentan (1-200 μM), and fialuridine (1-100 μM) from culture day 4 to 8. Chlorpromazine induced the most pronounced lipid alterations in human, monkey, and rat hepatocytes, while responses in dog hepatocytes were minimal, with human cells showing a dose-dependent trend up to 10 μM. Bosentan induced dose-dependent lipid changes across species, strongest in human hepatocytes, whereas fialuridine caused limited lipid alterations. Overall, lipidomic effects closely aligned with conventional toxicity markers, reflecting compound and species-specific hepatotoxic sensitivity. The targeted lipidomics workflow provided mechanism-informed phenotyping of chemical-induced lipid responses in cultured hepatocytes. Moreover, it provided a framework for mechanistic evaluation, supported cross-species comparison, and complemented in vitro hepatotoxicity assessments.
Exposure to Di-n-butyl phthalate (DBP) is associated with congenital and acquired defects in the male reproductive system, and DBP-induced oxidative stress plays a critical role in this process. The activation of the Nrf2 antioxidant pathway plays a protective role and its ubiquitin-dependent degradation is well-established. However, the role of Nrf2 SUMOylation remains unclear. This study investigated whether the de-SUMOylating enzyme SENP2 regulates the Nrf2 pathway and mediates DBP-induced damage in Leydig cells. In both DBP-exposed rat testes and TM3 cells, SENP2 expression was significantly downregulated. Molecular assays, including Ni2+-NTA pull-down and co-immunoprecipitation (co-IP), confirmed that Nrf2 is modified by SUMO2/3 at lysine 533 and that SENP2 mediates its de-SUMOylation. Gain- and loss-of-function assays in TM3 cells showed that SENP2 knockdown activated the Nrf2 pathway, facilitated Nrf2 nuclear translocation, upregulated downstream antioxidant proteins, lowered intracellular ROS levels, and partially rescued DBP-impaired testosterone secretion. Conversely, SENP2 overexpression suppressed Nrf2 activity and nuclear translocation, and exacerbated oxidative damage and secretory dysfunction. These findings indicate that SENP2 participates in DBP-induced Leydig cell oxidative injury by modulating the de-SUMOylation of Nrf2. This study provides novel insights into the post-translational regulation of Nrf2 in environmental toxicant-induced reproductive injury, identifying the SENP2/Nrf2 axis as a potential target for intervention.
Intra-articular administration of teicoplanin is a cost-effective therapeutic strategy for septic arthritis. Although teicoplanin has been reported to induce cytotoxicity in multiple cell types, the effects on human articular chondrocytes remain insufficiently characterized. In this study, primary human articular chondrocytes were subjected in vitro to increasing concentrations of teicoplanin (10, 50, 100, 200, and 400 μg/mL) to assess dose-dependent toxicity. Since inflamed cells exhibit altered biological responses, additional experiments were performed using interleukin-1 beta (IL-1β)-stimulated chondrocytes. High concentrations of teicoplanin (≥ 200 μg/mL) induced marked chondrotoxicity, while exposure to 100 μg/mL significantly reduced cell viability and proliferation in normal chondrocytes. Cellular senescence was observed following combined IL-1β and teicoplanin treatment; however, glycosaminoglycan production was not affected. Teicoplanin did not further modulate IL-1β-induced suppression of anabolic gene expression, including aggrecan, type II collagen, and tissue inhibitor of metalloproteinase-1. Similarly, the IL-1β-driven upregulation of pro-inflammatory and catabolic mediators—IL1B, IL6, matrix metalloproteinase-3 (MMP3), and MMP9—was not significantly changed by teicoplanin at the mRNA level. Consistently, the secretion of IL-1β, IL-6, and MMP-3 remained unchanged in IL-1β-stimulated chondrocytes following teicoplanin exposure. In conclusion, teicoplanin exhibits dose-dependent chondrotoxicity: concentrations ≥100 μg/mL impair chondrocyte viability, whereas concentrations ≤50 μg/mL are biologically tolerable. These findings provide toxicological evidence that local teicoplanin concentrations should be carefully controlled during intra-articular administration, supporting the use of the lowest concentration capable of achieving bactericidal activity while minimizing chondrotoxicity in the treatment of septic arthritis.
Fumonisin B1 (FB1) poses serious health concerns to human health. In this research, the cardiotoxic effects of FB1 were comprehensively evaluated through in vitro experiments using H9C2 cardiomyocytes and in vivo assays utilizing zebrafish. In H9C2 cells, exposure to 40 mg/L FB1 resulted in marked mitochondrial damage and apoptotic cell death. Transcriptomic profiling identified 1292 differentially expressed genes, with significant enrichment in pro-inflammatory signaling pathways, containing TNF, NOD-like receptor, and MAPK pathways. These findings were corroborated by the elevated expression of inflammatory mediators, i.e., IL-6, IL-8, and NF-κB, along with elevated phosphorylation of NF-κB p65 and MAPK ERK proteins, indicating the activation of these signaling cascades. In zebrafish, FB1 (40 mg/L) induced pronounced oxidative stress, cardiac malformations, functional disruptions, and heightened inflammatory responses. These molecular and functional disturbances ultimately resulted in compromised cardiac gene expression and physiological impairment, offering novel mechanistic insights into FB1-induced cardiovascular toxicity and underscoring its potential risk to cardiac health.
Dibutyl phthalate (DBP) is a widely used phthalate plasticizer and endocrine disruptor implicated in hepatic injury and fibrosis. However, its direct impact on hepatic stellate cells (HSCs) remains insufficiently characterized. In this study, we examined DBP-induced transcriptomic alterations and functional pathways in HSCs. RNA sequencing of 42,844 genes identified 981 significantly differentially expressed genes (FDR < 0.05), followed by validation using qPCR and Western blot analysis. Gene Ontology (GO) and KEGG enrichment analyses revealed strong activation of endoplasmic reticulum (ER) stress, autophagy, apoptosis, and calcium signaling pathways. Heatmap clustering further highlighted upregulation of ER stress- and autophagy-related genes, consistent with increased autophagic degradation and apoptotic signaling. Notably, genes regulating Ca2+ homeostasis were markedly dysregulated, showing enhanced expression of Ca2+-permeable channels and suppression of K+ channels, indicating a shift in intracellular ion dynamics. Collectively, DBP exposure severely disrupts HSC transcriptomic equilibrium through concerted activation of ER stress, autophagy, apoptosis, and calcium signaling. These findings identify ER stress-Ca2+ signaling crosstalk as a mechanistic hub linking DBP exposure to fibrogenic liver injury and establish a transcriptome-resolved framework for elucidating phthalate-induced hepatotoxicity and advancing risk assessment strategies.
Background Non-alcoholic fatty liver disease (NAFLD) is a growing global health concern, and its pathology is associated with impaired hepatic mitochondrial function and disrupted mitophagy. Emerging evidence highlights gut microbiota-derived metabolites as key regulators of NAFLD progression. Indole-3-propionic acid (IPA), a microbiota-derived tryptophan metabolite, has been linked to NAFLD development. However, its influence on mitophagy remains poorly defined. Methods In vitro, HepG2 cells were treated with free fatty acid (FFA) to establish a NAFLD model, followed by IPA treatment. The mRNA and protein expression levels were analyzed by qRT-PCR, Western blot, and immunofluorescence staining. Cell viability, oxidative stress, apoptosis, and mitochondrial function were assessed via CCK-8, ELISA, flow cytometry, and JC-1 staining. PINK1-USP4 interaction and ubiquitination were examined using co-IP and ubiquitination assays. Results Serum IPA levels were significantly reduced in NAFLD patients. In FFA-treated HepG2 cells, IPA attenuated oxidative injury while restoring mitochondrial function. Mechanistically, IPA activated PINK1/Parkin-mediated mitophagy by upregulating USP4, which stabilized PINK1 via deubiquitination. PINK1 or USP4 knockdown abolished IPA's protective effects against FFA-induced oxidative injury and mitophagy impairment in hepatocytes. Conclusion IPA alleviated FFA-induced oxidative injury in hepatocytes by activating PINK1/Parkin-mediated mitophagy via USP4-dependent PINK1 deubiquitination. These findings reveal a gut microbiota-mitochondria axis in NAFLD and suggest IPA as a potential therapeutic strategy targeting the USP4-PINK1 pathway.
Ambient fine particulate matter (PM2.5) is a leading global environmental risk factor for cardiovascular disease. Although PM2.5 exposure is known to lead to mitochondrial dysfunction, the precise metabolic mechanisms underlying this effect remain incompletely understood. In this study, we investigated the role of the mitochondrial deacetylase Sirt3 in PM2.5-induced cardiotoxicity using human induced pluripotent stem cell-derived cardiac organoids (hiPSC-COs), a physiologically relevant multicellular model. Our results demonstrated that PM2.5 exposure compromised the contractile function of COs. Specifically, it induced the expression of myocardial injury markers and triggered a series of mitochondrial impairments, including structural damage, inflammatory response, oxidative stress and loss of membrane potential. Mechanistically, exposure of COs to PM2.5 suppressed Sirt3 expression, leading to increased acetylation and decreased activity of malate dehydrogenase 2 (Mdh2), a key enzyme in the tricarboxylic acid (TCA) cycle. This disruption resulted in reduced levels of TCA cycle metabolites and a severe ATP deficit. Pharmacological activation of Sirt3 with dihydromyricetin attenuated the PM2.5-induced mitochondrial dysfunction, restored ATP levels and improved contractility. Our findings elucidate that PM2.5 impairs cardiac energy metabolism via the Sirt3/Mdh2 pathway, identifying Sirt3 as a potential therapeutic target for mitigating PM2.5-related cardiovascular dysfunction.
This study establishes an in vitro protocol using the EpiOral three-dimensional human buccal oral mucosal model to assess potential irritation from oral medical devices and their leachables. EpiOral tissues were exposed to test substances (e.g., methyl acetate, Triton X-100, sodium lauryl sulfate (SLS), phosphoric acid, benzalkonium chloride) at concentrations relevant to dental materials, with exposure time for 50% tissue viability (ET-50) calculated from viability assays at 1, 4, and 18 h. The application volumes of the test substances (40 μL and 100 μL), vehicle controls (saline, sesame oil), and a 50% viability cut-off were validated using linear mixed models (LMM), post-hoc comparisons, and ROC analysis with Youden's index. ET-50 assays correctly classified the test irritants: strong (e.g. SLS, phosphoric acid, ET-50 < 1 h), moderate (hydrogen peroxide, 1.12 h), and non-irritants (e.g., glycerol, polyethylene glycol >18 h). No significant viability differences occurred between 40 μL and 100 μL for most substances (p > 0.05), except hydrogen peroxide. Using a 50% viability cut-off for irritancy classification, all tested substances were correctly classified in this exploratory dataset (sensitivity/specificity = 1.000). The in vitro testing protocol using the EpiOral model provides a structured experimental approach for oral mucosal irritation assessment. Under the conditions evaluated in this study, a 100 μL application volume and a 50% viability threshold were found to be appropriate.
BACKGROUND:In HT-22 cells, 500 μM NMDA was used as a high-concentration oxidative stressor rather than a classical NMDA receptor-mediated excitotoxic stimulus. Because HT-22 cells lack functional ionotropic NMDA receptors, this model cannot test NMDA receptor antagonist-mediated pharmacology. METHODS:HT-22 cells and C8-D1A astrocytes were examined in a Transwell co-culture system. CCK-8 viability readout, ApoE Western blot signal, lipid peroxidation, BODIPY C12-associated fluorescence, TOMM20-region BODIPY C12 fluorescence, and MitoSOX fluorescence were assessed. RESULTS:NMDA exposure was associated with a lower CCK-8 viability readout and higher lipid peroxidation fluorescence. Esketamine treatment was associated with a higher CCK-8 viability readout and lower lipid peroxidation fluorescence under these oxidative stress conditions. In co-cultured astrocytes, NMDA-challenged HT-22 cells were associated with increased lipid peroxidation, altered BODIPY C12-associated fluorescence, and elevated MitoSOX fluorescence, whereas these signals were lower in the esketamine-treated condition. ApoE changes were descriptive and were not used to infer mechanism. The source and molecular identity of astrocytic BODIPY C12-associated fluorescence remain uncertain. CONCLUSIONS:Esketamine-associated effects in this model should be interpreted as receptor-independent, oxidative-stress-associated viability and fluorescence observations. The findings are descriptive and hypothesis-generating and do not establish direct lipid transfer, causal metabolic coupling, mitochondrial fatty-acid utilization, or a defined lipid-metabolic mechanism.
Polystyrene micro- and nanoplastics (MNPs) are widely used model particles in in vitro toxicology and represent a relevant fraction of environmental plastic pollution. Due to their small size and modifiable surface properties, MNPs interact with cellular membranes, undergo internalization, and influence intracellular signaling pathways. Reported biological effects range from oxidative stress and inflammation to minimal or absent toxicity. This review summarizes current in vitro evidence on cellular uptake, toxicological outcomes, and exocytosis of MNPs. Biological responses are strongly modulated by particle size, surface functionalization, aggregation state, concentration, and cell type. While smaller nanoparticles generally show higher uptake efficiency, internalization alone does not predict toxicity. Data indicate that the balance between endocytosis and exocytosis is a key determinant of intracellular effects. Efficient clearance may attenuate toxicity, whereas impaired trafficking and lysosomal accumulation promote organelle stress. Overall, MNPs behave as conditional toxicants in vitro, with their biological effects determined by their physicochemical properties and the cellular context. Standardized particle characterization and combined assessment of uptake and clearance are crucial for improving comparability and evaluating toxicological risk.
This study investigated the developmental toxicity of four cyanide-containing compounds (gold cyanide, sodium cyanide, zinc cyanide, and amygdalin) in zebrafish (Danio rerio) embryos. Fertilized eggs were exposed to concentrations ranging from 1 to 600 ng/mL for 96 h, following the OECD Test Guideline 236. Acute toxicity was determined by calculating the median lethal concentrations (LC₅₀), while developmental toxicity was assessed through a semi-quantitative scoring system based on six morphological endpoints: eye, heart, circulation, yolk sac, tail, and spontaneous movement. Of the compounds tested, amygdalin proved to be the most acutely toxic (LC₅₀ = 3.2 ng/mL), followed by sodium cyanide (6.3 ng/mL), zinc cyanide (33 ng/mL), and gold cyanide (90 ng/mL). A broadly similar toxicity ranking was observed for the severity of developmental malformations. These comparative data offer valuable insights for the environmental risk assessment of cyanide compounds, especially in areas impacted by active gold mining activities.
A new nasal formulation combining xylometazoline, a well-established nasal decongestant, and hyaluronic acid (HA) at a 3 mg/ml concentration and low-molecular-weight has been developed as a topical product intended for use in viral acute rhinosinusitis, with the aim of relieving nasal congestion and supporting epithelial integrity. HA, a moisturizing component of respiratory secretions, has been shown to promote epithelial integrity, stimulate mucociliary clearance and support wound healing. As part of the drug development process, this study investigated the permeation and penetration properties of xylometazoline and HA in the new formulation using a human nasal epithelium in vitro model. Results were compared to those of a xylometazoline mono-formulation and a well-established fixed-dose combination of xylometazoline and dexpanthenol. Morphological, ultrastructural and physiological analyses were performed to test nasal cells tolerability on prolonged drug exposure (6 h). HA in this new nasal formulation seems to be a component that exerts its effect mainly on the mucosal surface, which is the favoured site of action for topical products. HA was not detected in the basolateral compartment, consistent with retention at the mucosal surface. The results of our preclinical study do not indicate that the safety profile of xylometazoline would be altered by the addition of HA (or dexpanthenol). The barrier integrity of the in vitro human nasal epithelium was preserved across all tested formulations. Nanoparticle endocytosis was absent. These findings, obtained in a healthy in vitro nasal epithelial model, provide a valuable foundation for subsequent evaluation of this formulation in human clinical studies.
