Toxicology Mechanisms and Methods最新文献

This study focuses on the comparative metabolic profiling and effects of two steroid types: natural and synthetic, specifically 17α-methyl testosterone (17α-MT) at varying concentrations (1.5, 2, and 3 mg/kg) in rainbow trout (Oncorhynchus mykiss). Over a 75-day feeding trial, growth metrics, such as feed efficiency, daily specific growth, live weight gain, total weight gain, and survival rate were systematically monitored every 15 days. At the end of the feeding trial, histopathology, immunohistochemistry, and metabolome analyses were performed in the high-concentration groups (3 mg/kg natural and 3 mg/kg synthetic), in which the lowest survival rate was determined. Key findings reveal that the type of hormone significantly influences growth parameters. While some natural steroids enhanced certain growth aspects, synthetic variants often yielded better results. The metabolomic analysis highlighted significant shifts in the metabolism of tryptophan, purine, folate, primary bile acids, phosphonates, phosphinates, and xenobiotics via cytochrome P450 pathways. Histopathologically, the natural hormone groups showed similar testicular, hepatic, muscular, gill, cerebral, renal, and intestinal tissue structures to the control, with minor DNA damage and apoptosis observed through immunohistochemistry. Conversely, the synthetic hormone groups exhibited moderate DNA damage and mild degenerative and necrotic changes in histopathology.

Aluminum (Al) overexposure damages various organ systems, especially the nervous system. Regularly administered aluminum chloride (AlCl₃) to rats causes dementia and pathophysiological alterations linked to Alzheimer's disease (AD). Taxifolin's neuroprotective effects against AlCl₃-induced neurotoxicity in vitro and in vivo studies were studied. Taxifolin (0.1, 0.3, 1, 3, and 10 μM) was tested against AlCl₃ (5 mM)-induced neurotoxicity in C6 and SH-SY5Y cells using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) and lactate dehydrogenase (LDH) assays. Additionally, neural morphology was examined by confocal microscopy. Additionally, taxifolin's mode of binding with the co-receptor of toll-like receptor 4 (TLR4), human myeloid differentiation-2 (hMD-2) was investigated. AlCl₃ (25 mg/kg/d, i.p.) was administered to rats for 14 d, and from the eighth day, taxifolin (1, 2, and 5 mg/kg/d, i.p.) was given along with AlCl₃. This study assessed memory impairment using the Morris water maze, plus maze, and pole tests. This study also performed measurement of oxidant (malondialdehyde [MDA] and nitrite), antioxidant (reduced glutathione), and inflammatory (myeloperoxidase [MPO] activity, TLR4 expression) parameters in rats' brain in addition to histopathology. The docking score for taxifolin with hMD-2 was found to be -4.38 kcal/mol. Taxifolin treatment reduced the neurotoxicity brought on by AlCl₃ in both C6 and SH-SY5Y cells. Treatment with 10 μM taxifolin restored AlCl₃-induced altered cell morphology. AlCl₃ administration caused memory loss, oxidative stress, inflammation (increased MPO activity and TLR4 expression), and brain atrophy. Taxifolin treatment significantly improved the AlCl₃-induced memory impairment. Taxifolin treatment also mitigated the histopathological and neurochemical consequences of repeated AlCl₃ administration in rats. Thus, taxifolin may protect the brain against AD.

Recent studies have revealed a notable connection between pesticide exposure and Recurrent Pregnancy Loss (RPL), yet the precise molecular underpinning of this toxicity remains elusive. Through the alignment of Differentially Expressed Genes (DEGs) of healthy and RPL patients with the target genes of 9 pesticide components, we identified a set of 12 genes responsible for RPL etiology. Interestingly, biological process showed that besides RPL, those 12 genes also associated with preeclampsia and cardiovascular disease. Enrichment analysis showed the engagement of these genes associated with essential roles in the molecular transport of small molecules, as well as the aldosterone-regulated sodium reabsorption, endocrine and other factor-regulated calcium reabsorption, mineral absorption, ion homeostasis, and ion transport by P-type ATPases. Notably, the crosstalk targets between pesticide components played crucial roles in influencing RPL results, suggesting a role in attenuating pesticide agents that contribute to RPL. It is important to note that non-significant concentration of the pesticide components observed in both control and RPL samples should not prematurely undermine the potential for pesticides to induce RPL in humans. This study emphasizes the complexity of pesticide induced RPL and highlights avenues for further research and precautionary measures.

The modulatory role of primrose oil (PO) supplementation enriched with γ-linolenic acid and D/L-alpha tocopherol acetate against a carbon tetrachloride (CCl₄)-induced liver damage model was assessed in this study. Twenty male Albino rats were divided into four groups. The control group received corn oil orally. The PO group received 10 mg/kg P O orally. The CCl₄ group received 2 mL/kg CCl₄ orally and PO/CCl₄ group; received PO and 2 mL/kg CCl₄ orally. The relative liver weight was recorded. Serum liver enzymes, hepatic malondialdehyde (MDA), hepatic reduced glutathione (GSH) and the expression of hepatic tumor necrosis factor-alpha (TNF-α), interleukin 1 beta (IL-1β), and interleukin 6 (IL-6) were assessed. The binding affinities of γ-linolenic acid and D/L-alpha tocopherol constituents with IL-1β, IL-6 and TNF-α were investigated using molecular docking simulations. Histopathological and electron microscopic examinations of the liver were performed. The results indicated that CCl₄ elevated serum liver enzyme and hepatic MDA levels, whereas GSH levels were diminished. The upregulation of IL-1β, IL-6, and TNF-α gene expressions were induced by CCl₄ treatment. The PO/CCl4-treated group showed amelioration of hepatic injury biomarkers and oxidative stress. Restoration of histopathological and ultrastructural alterations while downregulations the gene expressions of TNF-α, IL1-β and IL-6 were observed. In conclusion, evening primrose oil enriched with γ-linolenic acid and D/L-alpha tocopherol acetate elicited a potential amelioration of CCl₄-induced hepatic toxicity.

This study aimed to examine the expression and biological functions of ACTL6A in glioma cells (U251), the effects of sulforaphane on the growth of U251 cells and the involvement of the ACTL6A/PGK1 pathway in those effects. The U251 cell line was transfected with ACTL6A over-expression plasmids to upregulate the protein, or with ACTL6A inhibitor to underexpress it, then treated with different concentrations of sulforaphane. Cell viability, proliferation, and apoptosis were assessed using standard assays, and levels of mRNAs encoding ACTL6A, PGK1, cyclin D1, Myc, Bax or Bcl-2 were measured using quantitative real-time polymerase chain reaction (qRT-PCR). ACTL6A and PGK1 were expressed at higher levels in glioma cell lines than in normal HEB cells. ACTL6A overexpression upregulated PGK1, whereas ACTL6A inhibition had the opposite effect. ACTL6A overexpression induced proliferation, whereas its inhibition repressed proliferation, enhanced apoptosis, and halted the cell cycle. Moreover, sulforaphane suppressed the growth of U251 cells by inactivating the ACTL6A/PGK1 axis. ACTL6A acts via PGK1 to play a critical role in glioma cell survival and proliferation, and sulforaphane targets it to inhibit glioma.

Irinotecan-induced severe diarrhea (IISD) not only limits irinotecan's application but also significantly affects patients' quality of life. However, existing animal models often inadequately represent the dynamics of IISD development, progression, and resolution across multiple chemotherapy cycles, yielding non-reproducible and highly variable response with limited clinical translation. Our studies aim to establish a reproducible and validated IISD model that better mimics the pathophysiology progression observed in patients, enhancing translational potential. We investigated the impact of dosing regimens (including different dose, infusion time, and two cycles of irinotecan administration), sex, age, tumor-bearing conditions, and irinotecan formulation on the IISD incidence and severity in mice and rats. Lastly, we investigated above factors' impact on pharmacokinetics of irinotecan, intestinal injury, and carboxylesterase activities. In summary, we successfully established a standard model establishment procedure for an optimized IISD model with highly reproducible severe diarrhea incidence rate (100%) and a low mortality rate (11%) in F344 rats. Additionally, the rats tolerated at least two cycles of irinotecan chemotherapy treatment. In contrast, the mouse model exhibited suboptimal IISD incidence rates (60%) and an extremely high mortality rate (100%). Notably, dosing regimen, age and tumor-bearing conditions of animals emerged as critical factors in IISD model establishment. In conclusion, our rat IISD model proves superior in mimicking pathophysiology progression and characteristics of IISD in patients, which stands as an effective tool for mechanism and efficacy studies in future chemotherapy-induced gut toxicity research.

Toxicity profiling is an integral part of the drug discovery pipeline. The 3Rs principle-Replacement, Reduction, and Refinement, is considered a golden rule in determining the most appropriate approach for toxicity studies. The acute toxicity study with proper estimate of median lethal dose (LD₅₀) is usually an initial procedure for the determination of most suitable test doses for preclinical toxicological and pharmacological profiling. Several methods, which have been devised to determine the LD₅₀, are faced with the challenge of using a large number of animals and time constraints. Despite the inherent advantage of the newer OECD Test Guidelines, the increasing concerns among toxicologists, the regulatory authorities and the general public, on the need to adhere to 3Rs principle, necessitated the need for an improved approach. Such an approach should not only minimize the time and number of animals required, but also take into cognizance animal welfare, and give accurate, comparable, and reproducible results across laboratories. While taking advantage of the inherent merits of the existing methods, here is presented the mathematical basis and evaluation of an improved method for toxicity profiling of test substances and estimation of LD₅₀. The method makes use of the generated Table of values for the selection of appropriate test doses. Our proposed method has capacities to optimize the time and number of animal use, ensure more reliable and reproducible results across laboratories, allow for easy selection of doses for subsequent toxicity profiling, and be adaptable to other biological screening beyond toxicity studies.

The current study aimed to assess the antioxidant and antiproliferative effects of teucrium polium extract: computational and in vivo study in rats. Three groups of animals: Group (i) constitute the control group; Group (ii) HeLa group received an intrafemoral inoculation of HeLa cells and Group (iii) constitue the combination between HeLa + T. polium. The plant was administered by gavage. Our results revealed that HeLa cell injection showed an elevation in aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), total bilirubin (TB), creatinine, urea, calcium and phosphorus. The pretreatment with the plant extract reduced the level of these parameters. Injection of HeLa cells showed a significant decrease in phosphorus and calcium respectively. However, the pretreatment by T. polium modulated the level of these two minerals. Rats treated with HeLa cells line showed an increase in the level of lipid peroxidation as evaluated by the TBARS substances, at the same time, a significant decreases in SOD, CAT and GPx activities were noted in the HeLa group compared to the control. On the other hand, pretreatment with the plant improved the level of these enzymes. Our results revealed that T.polium has a therapeutic effect on some health problems. HeLa cell line induced a small infiltration in liver and kidney. T. polium reduced the damage in both liver and kidney, but did not reveal any proliferation of tumor cells from trabecular bone tissue. The computational study revealed that T. polium compound bound with high free binding energies and established promising network of molecular interactions with COX-2 and TNF-α macromolecules.

Background: In a previous study, diethylstilbestrol (DES) was shown to induce oocyte maturation in fish. In the present study, the interaction of DES on goldfish membrane progesterone receptor α (GmPRα) was investigated using a competitive binding assay with radiolabeled steroids. The results indicate that DES exerts its effects on membrane progesterone receptor alpha (mPRα) and induces oocyte maturation through nongenomic steroid mechanisms. This study provides empirical data that demonstrate the binding between DES and GmPRα.

Methods: Binding of DES to GmPRα was achieved by using radiolabeled DES and recombinant GmPRα expressed in culture cells or purified GmPRα proteins that coupled to graphene quantum dots (GQDs). Additionally, the competitive binding of fluorescently labeled progesterone to GmPRα-expressing cells was evaluated.

Results: Although significant nonspecific binding of radiolabeled DES to the cell membrane that expresses GmPRα has been observed, specific binding of DES to GmPRα has been successfully identified in the presence of digitonin. Furthermore, the specific binding of DES to GmPRα was confirmed by a binding assay using GQD-GmPRα. The radiolabeled DES was shown to bind to GQD-GmPRα. Additionally, the competition for the binding of fluorescently labeled progesterone to GmPRα-expressing cells was achieved with the DES.

Conclusions: The results of the experiments revealed that DES binds to GmPRα. Thus, it can be concluded that DES induces goldfish oocyte maturation by binding to GmPRα.