A comparison of the effect of lead nitrate on rat liver chromatin, DNA and histone proteins in solution

To explore the protective effect of gastrodin on PC12 cells against oxidative stress induced by lead acetate based on network pharmacology

Objective

Screening and predicting potential targets for gastrodin antioxidant stress based on network pharmacology methods, and exploring the effect of gastrodin on lead acetate induced oxidative stress in PC12 cells through cell experiments.

Methods

Through the Pharmaper database Predict the target of action of gastrodin. Through OMIM and GeneCards to collect oxidative stress targets from database, and intersect with drug targets to obtain drug disease intersection targets; Construct a PPI network diagram using the STRING database. Perform GO enrichment analysis and KEGG pathway enrichment analysis on intersection targets through the DAVID platform. Lead acetate (PbAc) exposure was used to establish a lead poisoning cell model, and intracellular ROS levels, ALB, AKT1, and Caspase-3 levels were measured.

Results

A total of 288 targets of gastrodin action, 638 targets related to oxidative stress, and 62 drug disease intersection targets were obtained, among which core targets such as ALB, AKT1, CASP3 may be closely related to oxidative stress. KEGG pathway analysis showed that gastrodin antioxidant stress mainly involved in lipid, cancer pathway and other signaling pathways. The results of the cell experiment showed that 50 μM is the optimal effective concentration for PbAc induced ROS production in PC12 cells. Gastrodin significantly increased the ROS content of PC12 cells treated with PbAc, Upregulation of ALB expression and downregulation of AKT1 and CASP3 expression.

Conclusions

Gastrodin may alleviate PbAc-induced ROS in PC12 cells, indicating potential protective effects against oxidative stress. Further studies are needed to confirm these findings and explore the underlying mechanisms.

The Role of Lead and Cadmium in Gynecological Malignancies

Lead and cadmium are non-essential and toxic heavy metals. Their presence and elevated levels can lead to many pathologies. They disrupt the antioxidant properties of many enzymes, consume the resources of antioxidant cells, and thus participate in the generation of oxidative stress, which may result in DNA damage. In addition, they have been found to be carcinogenic through their genotoxic properties. They have been shown to be present in various types of cancer, including cancer of the female reproductive system. Both metals have been recognized as metalloestrogens, which are important in hormone-related cancers. Participation in the oncogenesis of ovarian, endometrial and cervical cancer was analysed in detail, using the available research in this field. We emphasize their role as potential biomarkers in cancer risk and diagnosis as well as advancement of gynaecological malignancies.

Long-term probiotic intervention mitigates memory dysfunction through a novel H3K27me3-based mechanism in lead-exposed rats

Chronic lead exposure is associated with the development of neurodegenerative diseases, characterized by the long-term memory decline. However, whether this pathogenesis could be prevented through adjusting gut microbiota is not yet understood. To address the issue, pregnant rats and their female offspring were treated with lead (125 ppm) or separately the extra probiotics (10¹⁰ organisms/rat/day) till adulthood. For results, memory dysfunction was alleviated by the treatment of multispecies probiotics. Meanwhile, the gut microbiota composition was partially normalized against lead-exposed rats, which in turn mediated the memory repairment via fecal transplantation trials. In the molecular aspect, the decreased H3K27me3 (trimethylation of histone H3 Lys 27) in the adult hippocampus was restored with probiotic intervention, an epigenetic event mediated by EZH2 (enhancer of zeste homolog 2) at early developmental stage. In a neural cellular model, EZH2 overexpression showed the similar rescue effect with probiotics, whereas its blockade led to the neural re-damages. Regarding the gut-brain inflammatory mediators, the disrupted IL-6 (interleukin 6) expression was resumed by probiotic treatment. Intraperitoneal injection of tocilizumab, an IL-6 receptor antagonist, upregulated the hippocampal EZH2 level and consequently alleviated the memory injuries. In conclusion, reshaping gut microbiota could mitigate memory dysfunction caused by chronic lead exposure, wherein the inflammation-hippocampal epigenetic pathway of IL-6-EZH2-H3K27me3, was first proposed to mediate the studied gut-brain communication. These findings provided insight with epigenetic mechanisms underlying a unique gut-brain interaction, shedding light on the safe and non-invasive treatment of neurodegenerative disorders with environmental etiology.

Lead, selenium and nickel concentrations in epithelial ovarian cancer, borderline ovarian tumor and healthy ovarian tissues

OBJECTIVE

Wide variation exists in ovarian cancer incidence rates suggesting the importance of environmental factors. Due to increasing environmental pollution, trace elements and heavy metals have drawn attention in studies defining the etiology of cancer, but scant data is available for ovarian cancer. Our aim was to compare the tissue concentrations of lead, selenium and nickel in epithelial ovarian cancer, borderline tumor and healthy ovarian tissues.

METHODS

The levels of lead, selenium and nickel were estimated using atomic absorption spectrophotometry in formalin-fixed paraffin-embedded tissue samples. Tests were carried out in 20 malignant epithelial ovarian cancer, 15 epithelial borderline tumor and 20 non-neoplastic healthy ovaries. Two samples were collected for borderline tumors, one from papillary projection and one from the smooth surface of cyst wall.

RESULTS

Pb and Ni concentrations were found to be higher both in malignant and borderline tissues than those in healthy ovaries. Concentrations of Pb and Ni in malignant tissues, borderline papillary projections and capsular tissue samples were not different. Comparison of Se concentrations of malignant, borderline and healthy ovarian tissues did not reveal statistical difference. Studied metal levels were not found to be different in either papillary projection or in cyst wall of the borderline tumors.

CONCLUSIONS

This study revealed the accumulation of lead and nickel in ovarian tissue is associated with borderline and malignant proliferation of the surface epithelium. Accumulation of these metals in epithelial ovarian cancer and borderline ovarian tumor has not been demonstrated before.

Genotoxicity of two heavy metal compounds: lead nitrate and cobalt chloride in Polychaete Perinereis cultrifera

The present study explores the in vivo and in vitro genotoxic effects of lead nitrate, [Pb(NO₃)₂] a recognized environmental pollutant and cobalt chloride (CoCl₂), an emerging environmental pollutant in polychaete Perinereis cultrifera using comet assay. Despite widespread occurrence and extensive industrial applications, no previous published reports on genotoxicity of these compounds are available in polychaete as detected by comet assay. Polychaetes were exposed in vivo to Pb(NO₃)₂ (0, 100, 500, and 1000 μg/l) and CoCl₂ (0, 100, 300, and 500 μg/l) for 5 days. At 100 μg/l Pb(NO₃)₂ concentration, tail DNA (TDNA) values in coelomocytes were increase by 1.16, 1.43, and 1.55-fold after day 1, day 3, and day 5, whereas, OTM showed 1.12, 2.33, and 2.10-fold increase in in vivo. Pb(NO₃)₂ showed a concentration and time-dependent genotoxicity whereas CoCl₂ showed a concentration-dependent genotoxicity in in vivo. A concentration-dependent increase in DNA damage was observed in in vitro studies for Pb(NO₃)₂ and CoCl₂. DNA damage at 500 μg/L showed almost threefold increase in TDNA and approximately fourfold increase in OTM as compared to control in in vitro. Our studies suggest that Pb(NO₃)₂ and CoCl₂ have potential to cause genotoxic damage, with Pb(NO₃)₂ being more genotoxic in polychaete and should be used more carefully in industrial and other activities. Graphical abstract.

Lithium attenuates lead induced toxicity on mouse non-adherent bone marrow cells

Lead is a poisonous heavy metal that occurs in all parts of environment and causes serious health problems in humans. The aim of the present study was to investigate the possible protective effect of lithium against lead nitrate induced toxicity in non-adherent bone marrow stem cells. Trypan blue and MTT assays represented that exposure of the cells to different concentrations of lead nitrate decreased viability in a dose dependent manner, whereas, pretreatment of the cells with lithium protected the cells against lead toxicity. Lead reduced the number and differentiation status of bone marrow-derived precursors when cultured in the presence of colony stimulating factor (CSF), while the effect was attenuated by lithium. The cells treated with lead nitrate exhibited cell shrinkage, DNA fragmentation, anion superoxide production, but lithium prevented lead action. Moreover, apoptotic indexes such as PARP cleavage and release of HMGB1 induced by lead, were protected by lithium, suggesting anti-apoptotic effect of lithium. Immunoblot analysis of histone H3K9 acetylation indicated that lithium overcame lead effect on acetylation. In conclusion, lithium efficiently reduces lead toxicity suggesting new insight into lithium action which may contribute to increased cell survival. It also provides a potentially new therapeutic strategy for lithium and a cost-effective approach to minimize destructive effects of lead on bone marrow stem cells.

DNA Damage, Cell Cycle Arrest, and Apoptosis Induction Caused by Lead in Human Leukemia Cells

In recent years, the industrial use of lead has been significantly reduced from paints and ceramic products, caulking, and pipe solder. Despite this progress, lead exposure continues to be a significant public health concern. The main goal of this research was to determine the in vitro mechanisms of lead nitrate [Pb(NO₃)₂] to induce DNA damage, apoptosis, and cell cycle arrest in human leukemia (HL-60) cells. To reach our goal, HL-60 cells were treated with different concentrations of Pb(NO₃)₂ for 24 h. Live cells and necrotic death cells were measured by the propidium idiode (PI) assay using the cellometer vision. Cell apoptosis was measured by the flow cytometry and DNA laddering. Cell cycle analysis was evaluated by the flow cytometry. The result of the PI demonstrated a significant (p < 0.05) increase of necrotic cell death in Pb(NO₃)₂-treated cells, indicative of membrane rupture by Pb(NO₃)₂ compared to the control. Data generated from the comet assay indicated a concentration-dependent increase in DNA damage, showing a significant increase (p < 0.05) in comet tail-length and percentages of DNA cleavage. Data generated from the flow cytometry assessment indicated that Pb(NO₃)₂ exposure significantly (p < 0.05) increased the proportion of caspase-3 positive cells (apoptotic cells) compared to the control. The flow cytometry assessment also indicated Pb(NO₃)₂ exposure caused cell cycle arrest at the G₀/G₁ checkpoint. The result of DNA laddering assay showed presence of DNA smear in the agarose gel with little presence of DNA fragments in the treated cells compared to the control. In summary, Pb(NO₃)₂ inhibits HL-60 cells proliferation by not only inducing DNA damage and cell cycle arrest at the G₀/G₁ checkpoint but also triggering the apoptosis through caspase-3 activation and nucleosomal DNA fragmentation accompanied by secondary necrosis. We believe that our study provides a new insight into the mechanisms of Pb(NO₃)₂ exposure and its associated adverse health effects.

Mitogen-activated protein kinase signaling and its association with oxidative stress and apoptosis in lead-exposed hepatocytes

Lead toxicity has become a serious public health concern all over the world. Previous studies have shown that lead induces biochemical and structural changes in liver. However, although lead is known to alter liver functions, the underlying molecular mechanisms of hepatotoxicity are not yet clear. We hypothesized that a correlation exists between oxidative stress, apoptosis and mitogen-activated protein kinases (MAPKs) in lead-exposed liver. Wistar rats were treated with 0, 0.5%, and 1% lead acetate for 3d, 14d, and 35d and sacrificed the next day. On 4d, oxidative stress and apoptosis were correlated with downregulated expressions of ERK1/2 and p38-MAPKα/β, and upregulated expressions of JNK1/3 in males. In females, the correlation was with downregulated expressions of ERK1/2 and upregulated expressions of p38-MAPKα/β and JNK1/3. On 15d, the correlation was observed with upregulated expressions of p38-MAPKα/β in males and downregulated expressions of p38-MAPKα/β in females. In both sexes, a correlation was observed with upregulated expressions of ERK1/2 and JNK1/3 in 1% groups. On 36d, the correlation was observed with downregulated expressions of p38-MAPKα/β in males and their upregulated expressions in females. Time-dependent increase in lipid peroxidation on 15d and 36d correlated with upregulated expressions of p38-MAPKα/β in females and ERK1/2 in 1% groups in both sexes. The lower dose induced more apoptosis up to 15d in females and the higher dose induced in males on 36d. Generally, the female livers had more p38-MAPKα/β than the male livers. On 36d, the female livers showed more p38-MAPKα/β and JNK1/3 than the male livers. In conclusion, although not clearly defined, a correlation exists among oxidative stress, apoptosis, and the MAPKs in lead-exposed hepatocytes. The sex-dependent effects may be due to differences in hormonal or other physiological mechanisms. In lead-exposed hepatocytes, the apoptosis may be induced via oxidative stress-mediated alterations in the MAPKs.

Diverse effects of lead nitrate on the proliferation, differentiation, and gene expression of stem cells isolated from a dental origin

Lead (Pb²⁺) exposure continues to be a significant public health problem. Therefore, it is vital to have a continuous epidemiological dataset for a better understanding of Pb²⁺ toxicity. In the present study, we have exposed stem cells isolated from deciduous and permanent teeth, periodontal ligament, and bone marrow to five different types of Pb²⁺ concentrations (160, 80, 40, 20, and 10 µM) for 24 hours to identify the adverse effects of Pb²⁺ on the proliferation, differentiation, and gene expression on these cell lines. We found that Pb²⁺ treatment altered the morphology and adhesion of the cells in a dose-dependent manner. There were no significant changes in terms of cell surface phenotypes. Cells exposed to Pb²⁺ continued to differentiate into chondrogenesis and adipogenesis, and a severe downregulation was observed in osteogenesis. Gene expression studies revealed a constant expression of key markers associated with stemness (Oct 4, Rex 1) and DNA repair enzyme markers, but downregulation occurred with some ectoderm and endoderm markers, demonstrating an irregular and untimely differentiation trail. Our study revealed for the first time that Pb²⁺ exposure not only affects the phenotypic characteristics but also induces significant alteration in the differentiation and gene expression in the cells.