Neonatal Benzo[a]pyrene Exposure Induces Oxidative Stress and DNA Damage Causing Neurobehavioural Changes during the Early Adolescence Period in Rats

2016 ◽  
Vol 38 (2) ◽  
pp. 150-162 ◽  
Author(s):  
Bhupesh Patel ◽  
Saroj Kumar Das ◽  
Manorama Patri

Humans are exposed to polycyclic aromatic hydrocarbons (PAHs) by ingestion of contaminated food and water. Prenatal exposure to benzo[a]pyrene (B[a]P) like PAHs through the placental barrier and neonatal exposure by breast milk and the environment may affect early brain development. In the present study, single intracisternal administration of B[a]P (0.2 and 2.0 µg/kg body weight) to male Wistar rat pups at postnatal day 5 (PND5) was carried out to study its specific effect on neonatal brain development and its consequences at PND30. B[a]P administration showed a significant increase in exploratory and anxiolytic-like behaviour with elevated hippocampal lipid peroxidation and protein oxidation at PND30. Further, DNA damage was estimated in vitro (Neuro2a and C6 cell lines) by the comet assay, and oxidative DNA damage of hippocampal sections was measured in vivo following exposure to B[a]P. DNA strand breaks (single and double) significantly increased due to B[a]P at PND30 in hippocampal neurons and increased the nuclear tail moment in Neuro2a cells. Hippocampal 8-oxo-2′-deoxyguanosine production was significantly elevated showing expression of more TUNEL-positive cells in both doses of B[a]P. Histological studies also revealed a significant reduction in mean area and perimeter of hippocampal neurons in rats treated with B[a]P 2.0 μg/kg, when compared to naïve and control rats. B[a]P significantly increased anxiolytic-like behaviour and oxidative DNA damage in the hippocampus causing apoptosis that may lead to neurodegeneration in adolescence. The findings of the present study address the potential role of B[a]P in inducing oxidative stress-mediated neurodegeneration in the hippocampus through oxidative DNA damage in the early adolescence period of rats.

2006 ◽  
Vol 74 (12) ◽  
pp. 6839-6846 ◽  
Author(s):  
Ge Wang ◽  
Yang Hong ◽  
Adriana Olczak ◽  
Susan E. Maier ◽  
Robert J. Maier

ABSTRACT Neutrophil-activating protein (NapA) has been well documented to play roles in human neutrophil recruitment and in stimulating host cell production of reactive oxygen intermediates (ROI). A separate role for NapA in combating oxidative stress within H. pylori was implied by studies of various H. pylori mutant strains. Here, physiological analysis of a napA strain was the approach used to assess the iron-sequestering and stress resistance roles of NapA, its role in preventing oxidative DNA damage, and its importance to mouse colonization. The napA strain was more sensitive to oxidative stress reagents and to oxygen, and it contained fourfold more intracellular free iron and more damaged DNA than the parent strain. Pure, iron-loaded NapA bound to DNA, but native NapA did not, presumably linking iron levels sensed by NapA to DNA damage protection. Despite its in vitro phenotype of sensitivity to oxidative stress, the napA strain showed normal (like that of the wild type) mouse colonization efficiency in the conventional in vivo assay. By use of a modified mouse inoculation protocol whereby nonviable H. pylori is first inoculated into mice, followed by (live) bacterial strain administration, an in vivo role for NapA in colonization efficiency could be demonstrated. NapA is the critical component responsible for inducing host-mediated ROI production, thus inhibiting colonization by the napA strain. An animal colonization experiment with a mixed-strain infection protocol further demonstrated that the napA strain has significantly decreased ability to survive when competing with the wild type. H. pylori NapA has unique and separate roles in gastric pathogenesis.


Circulation ◽  
2008 ◽  
Vol 118 (suppl_18) ◽  
Author(s):  
Marion Hofmann Bowman ◽  
Jeannine Wilk ◽  
Gene Kim ◽  
Yanmin Zhang ◽  
Jalees Rehman ◽  
...  

S100A12 is a small calcium binding protein that is a signal transduction ligand of the receptor for advance glycation endproducts (RAGE). S100A12, like RAGE, is expressed in the vessel wall of atherosclerotic vasculature, particularly in smooth muscle cells (SMC). While RAGE has been extensively implicated in inflammatory states such as atherosclerosis, the role of S100A12 is less clear. We tested the hypothesis that expression of human S100A12 directly exacerbates vascular inflammation. Several lines of Bl6/J transgenic mice (tg) expressing human S100A12 in SMC under control of the SM22a promoter were generated. Primary aortic SMC from tg and wild type (wt) littermates were isolated and analyzed for (i) proliferation using MTS/Formazan Assay and BrdU incorporation, (ii) oxidative stress using using flow cytometry with MitoSOX antibody, oxidative DNA damage using immunofluorescence microscopy with anti-8-oxo-dG antibody, and NF-kB activation measured by EMSA and (iii) cytokine expression measured by IL-6 ELISA. Furthermore, the aortas from tg and wt mice were examined. Results: Tg but not wt SMC expressed S100A12 protein. Tg SMC had a significant 1.9 to 2.7 fold increase in conversion of MTS into Formazan at 24–96 hours likely reflective of increased metabolic activity since BrdU incorporation into DNA was less in tg compared to wt SMC (4% vs 21% positive BrdU nuclei, p <0.05). Tg SMC showed significantly higher levels of mitochondrial generated ROS, nuclear staining for oxidative DNA damage which was not detected in the nuclei of wt SMC’s, and a 2.5 fold increase in NFkB activity. IL-6 production at baseline was higher in tg SMC’s (615 vs 213 pg/ml, p< 0.05) and increased dramatically after LPS treatment (10 ng/ml) in tg SMC’s (2130 vs 415 pg/ml). Histologic examination of the thoracic aorta at 10 weeks of age revealed increased collagen deposition in the aortic media with fragmentation and disarray of elastic fibers. In vivo ultrasound revealed a progressive dilation of the aortic arch from age 10 weeks to 16 weeks of age (1.27 to 1.60 mm, p<0.05) in tg but not in wt littermate mice (1.30 to 1.33 mm, p=0.1). These data reveal the novel finding that targeted expression of human S100A12 in SMC modulates oxidative stress, inflammation and vascular remodeling.


2018 ◽  
Vol 115 (39) ◽  
pp. 9779-9784 ◽  
Author(s):  
Sangeeta Tiwari ◽  
Andries J. van Tonder ◽  
Catherine Vilchèze ◽  
Vitor Mendes ◽  
Sherine E. Thomas ◽  
...  

Reactive oxygen species (ROS)-mediated oxidative stress and DNA damage have recently been recognized as contributing to the efficacy of most bactericidal antibiotics, irrespective of their primary macromolecular targets. Inhibitors of targets involved in both combating oxidative stress as well as being required for in vivo survival may exhibit powerful synergistic action. This study demonstrates that the de novo arginine biosynthetic pathway in Mycobacterium tuberculosis (Mtb) is up-regulated in the early response to the oxidative stress-elevating agent isoniazid or vitamin C. Arginine deprivation rapidly sterilizes the Mtb de novo arginine biosynthesis pathway mutants ΔargB and ΔargF without the emergence of suppressor mutants in vitro as well as in vivo. Transcriptomic and flow cytometry studies of arginine-deprived Mtb have indicated accumulation of ROS and extensive DNA damage. Metabolomics studies following arginine deprivation have revealed that these cells experienced depletion of antioxidant thiols and accumulation of the upstream metabolite substrate of ArgB or ArgF enzymes. ΔargB and ΔargF were unable to scavenge host arginine and were quickly cleared from both immunocompetent and immunocompromised mice. In summary, our investigation revealed in vivo essentiality of the de novo arginine biosynthesis pathway for Mtb and a promising drug target space for combating tuberculosis.


Materials ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4062
Author(s):  
Till Jasper Meyer ◽  
Agmal Scherzad ◽  
Helena Moratin ◽  
Thomas Eckert Gehrke ◽  
Julian Killisperger ◽  
...  

Radioresistance is an important cause of head and neck cancer therapy failure. Zinc oxide nanoparticles (ZnO-NP) mediate tumor-selective toxic effects. The aim of this study was to evaluate the potential for radiosensitization of ZnO-NP. The dose-dependent cytotoxicity of ZnO-NP20 nm and ZnO-NP100 nm was investigated in FaDu and primary fibroblasts (FB) by an MTT assay. The clonogenic survival assay was used to evaluate the effects of ZnO-NP alone and in combination with irradiation on FB and FaDu. A formamidopyrimidine-DNA glycosylase (FPG)-modified single-cell microgel electrophoresis (comet) assay was applied to detect oxidative DNA damage in FB as a function of ZnO-NP and irradiation exposure. A significantly increased cytotoxicity after FaDu exposure to ZnO-NP20 nm or ZnO-NP100 nm was observed in a concentration of 10 µg/mL or 1 µg/mL respectively in 30 µg/mL of ZnO-NP20 nm or 20 µg/mL of ZnO-NP100 nm in FB. The addition of 1, 5, or 10 µg/mL ZnO-NP20 nm or ZnO-NP100 nm significantly reduced the clonogenic survival of FaDu after irradiation. The sub-cytotoxic dosage of ZnO-NP100 nm increased the oxidative DNA damage compared to the irradiated control. This effect was not significant for ZnO-NP20 nm. ZnO-NP showed radiosensitizing properties in the sub-cytotoxic dosage. At least for the ZnO-NP100 nm, an increased level of oxidative stress is a possible mechanism of the radiosensitizing effect.


Nanomaterials ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 504 ◽  
Author(s):  
Hainan Sun ◽  
Xiaoling Wang ◽  
Shumei Zhai

Radiotherapy (RT) has been widely used for cancer treatment. However, the intrinsic drawbacks of RT, such as radiotoxicity in normal tissues and tumor radioresistance, promoted the development of radiosensitizers. To date, various kinds of nanoparticles have been found to act as radiosensitizers in cancer radiotherapy. This review focuses on the current state of nanoradiosensitizers, especially the related biological mechanisms, and the key design strategies for generating nanoradiosensitizers. The regulation of oxidative stress, DNA damage, the cell cycle, autophagy and apoptosis by nanoradiosensitizers in vitro and in vivo is highlighted, which may guide the rational design of therapeutics for tumor radiosensitization.


2017 ◽  
Vol 2017 ◽  
pp. 1-17 ◽  
Author(s):  
Peng Wang ◽  
Qian Luo ◽  
Hui Qiao ◽  
Hui Ding ◽  
Yonggang Cao ◽  
...  

Chronic alcohol consumption causes hippocampal neuronal impairment, which is associated with oxidative stress and apoptosis. Carvacrol is a major monoterpenic phenol found in essential oils from the family Labiatae and has antioxidative stress and antiapoptosis actions. However, the protective effects of carvacrol in ethanol-induced hippocampal neuronal impairment have not been fully understood. We explored the neuroprotective effects of carvacrol in vivo and in vitro. Male C57BL/6 mice were exposed to 35% ethanol for 4 weeks to establish ethanol model in vivo, and hippocampal neuron injury was simulated by 200 mM ethanol in vitro. Morris water maze test was performed to evaluate the cognitive dysfunction. The oxidative stress injury of hippocampal neurons was evaluated by measuring the levels of oxidative stress biomarkers. Histopathological examinations and western blot were performed to evaluate the apoptosis of neurons. The results showed that carvacrol attenuates the cognitive dysfunction, oxidative stress, and apoptosis of the mice treated with ethanol and decreases hippocampal neurons apoptosis induced by ethanol in vitro. In addition, western blot analysis revealed that carvacrol modulates the protein expression of Bcl-2, Bax, caspase-3, and p-ERK, without influence of p-JNK and p-p38. Our results suggest that carvacrol alleviates ethanol-mediated hippocampal neuronal impairment by antioxidative and antiapoptotic effects.


2010 ◽  
Vol 30 (11) ◽  
pp. 2681-2692 ◽  
Author(s):  
Nilotpal Roy ◽  
Tanya Stoyanova ◽  
Carmen Dominguez-Brauer ◽  
Hyun Jung Park ◽  
Srilata Bagchi ◽  
...  

ABSTRACT Reactive oxygen species (ROS) is critical for premature senescence, a process significant in tumor suppression and cancer therapy. Here, we reveal a novel function of the nucleotide excision repair protein DDB2 in the accumulation of ROS in a manner that is essential for premature senescence. DDB2-deficient cells fail to undergo premature senescence induced by culture shock, exogenous oxidative stress, oncogenic stress, or DNA damage. These cells do not accumulate ROS following DNA damage. The lack of ROS accumulation in DDB2 deficiency results from high-level expression of the antioxidant genes in vitro and in vivo. DDB2 represses antioxidant genes by recruiting Cul4A and Suv39h and by increasing histone-H3K9 trimethylation. Moreover, expression of DDB2 also is induced by ROS. Together, our results show that, upon oxidative stress, DDB2 functions in a positive feedback loop by repressing the antioxidant genes to cause persistent accumulation of ROS and induce premature senescence.


2021 ◽  
Vol 13 ◽  
Author(s):  
Jia Sun ◽  
Jinzhong Cai ◽  
Junhui Chen ◽  
Siqiaozhi Li ◽  
Xin Liao ◽  
...  

As a severe neurological deficit, intracerebral hemorrhage (ICH) is associated with overwhelming mortality. Subsequent oxidative stress and neurological dysfunction are likely to cause secondary brain injury. Therefore, this study sought to define the role of Krüppel-like factor 6 (KLF6) and underlying mechanism in oxidative stress and neurological dysfunction following ICH. An in vivo model of ICH was established in rats by injection of autologous blood, and an in vitro ICH cell model was developed in hippocampal neurons by oxyhemoglobin (OxyHb) exposure. Next, gain- and loss-of-function assays were performed in vivo and in vitro to clarify the effect of KLF6 on neurological dysfunction and oxidative stress in ICH rats and neuronal apoptosis and mitochondrial reactive oxygen species in OxyHb-induced hippocampal neurons. KLF6, nuclear factor erythroid 2–related factor 2 (Nrf2), and heme oxygenase 1 (HO-1) were highly expressed in hippocampal tissues of ICH rats, whereas sirtuin 5 (SIRT5) presented a poor expression. Mechanistically, KLF6 bound to the SIRT5 promoter and transcriptionally repressed SIRT5 to activate the Nrf2/HO-1 signaling pathway. KLF6 silencing alleviated neurological dysfunction and oxidative stress in ICH rats and diminished oxidative stress and neuronal apoptosis in OxyHb-induced neurons, whereas SIRT5 overexpression negated its effect. To sum up, KLF6 silencing elevated SIRT5 expression to inactivate the Nrf2/HO-1 signaling pathway, thus attenuating oxidative stress and neurological dysfunction after ICH.


2019 ◽  
Vol 35 (4) ◽  
pp. 294-303 ◽  
Author(s):  
Asad Ullah ◽  
Madeeha Pirzada ◽  
Sarwat Jahan ◽  
Hizb Ullah ◽  
Muhammad Jamil Khan

Bisphenol A (BPA) is a well-known endocrine-disrupting chemical with estrogenic activity. The widespread exposure of individuals to BPA is suspected to affect a variety of physiological functions, including reproduction, development, and metabolism. Here we report the mechanisms by which BPA and three of its analogues bisphenol B (BPB), bisphenol F (BPF), and bisphenol S (BPS) cause generation of reactive oxygen species (ROS), sperm DNA damage, and oxidative stress in both in vivo and in vitro rat models. Sperm were incubated with different concentrations (1, 10, and 100 µg/L) of BPA and its analogues BPB, BPF, and BPS for 2 h. BPA and its analogues were observed to increase DNA fragmentation, formation of ROS, and affected levels of superoxide dismutase at higher concentration groups. In an in vivo experiment, rats were exposed to different concentrations (5, 25, and 50 mg/kg/day) of BPA, BPB, BPF, and BPS for 28 days. In the higher dose (50 mg/kg/day) treated groups of BPA and its analogues BPB, BPF, and BPS, DNA damage was observed while the motility of sperm was not affected.


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