Oxidative Stress-mediated Mechanism Research Articles

Long-term tributyltin exposure alters behavior, oocyte maturation, and histomorphology of the ovary due to oxidative stress in adult zebrafish

Tributyltin (TBT), an organotin endocrine-disrupting substance, is recognized as one of the important toxic environmental pollutants. The present study was carried out to investigate the toxic effects of TBT on behavior and the ovary of adult zebrafish with a focus on oxidative stress markers and oocyte maturation. Adult zebrafish were exposed to three different concentrations (125, 250, and 500 ng/L of water) of TBT for 28 days. TBT exposure produced a concentration-dependent negative effect on the body weight and behavior (anxiety-like symptoms) of adult zebrafish. Alterations in the activity of superoxide dismutase (SOD) and catalase (CAT), the total antioxidant capacity of ovarian tissue by the highest exposure level of TBT resulted in lipid peroxidation as indicated by increased malondialdehyde (MDA) level. The numbers of early-vitellogenic oocytes were significantly increased in zebrafish exposed to TBT as low as 125 ng/L. However, the numbers and size of fully-grown (mature) oocytes were significantly reduced in the highest exposure group only. Correlation between the MDA level and pre-vitellogenic oocytes in the 500 ng/L group indicated that lipid peroxidation prevented the maturation of pre-vitellogenic oocytes. TBT exposure produced significant histological changes in the ovary as evidenced by disturbed maturation of oocytes. In conclusion, TBT adversely affected the maturation of oocytes in zebrafish ovary through oxidative stress-mediated mechanisms.

Excavatolide C/cisplatin combination induces antiproliferation and drives apoptosis and DNA damage in bladder cancer cells.

Excavatolide C (EXCC), a marine coral-derived compound, exhibits an antiproliferation effect on bladder cancer cells. The present study evaluated the improvement in the antiproliferation ability of EXCC by co-treatment with cisplatin in bladder cancer cells. EXCC/cisplatin (12.5 and 1μg/mL) showed higher antiproliferation effects on bladder cancer cells than single treatments (EXCC or cisplatin alone) in the 48h ATP assay. EXCC/cisplatin also enhanced the increase in subG1, annexin V-mediated apoptosis, and activation of poly (ADP-ribose) polymerase (PARP) and several caspases (caspases 3, 8, and 9) compared to the single treatments. Cellular and mitochondrial oxidative stress was enhanced with EXCC/cisplatin compared to the single treatments according to analyses of reactive oxygen species (ROS), mitochondrial superoxide, and mitochondrial membrane potential; in addition, cellular antioxidants, such as glutathione (GSH), and the mRNA expressions of antioxidant signaling genes (catalase and NFE2-like bZIP transcription factor 2) were downregulated. EXCC/cisplatin treatment produced more DNA damage than the single treatments, as indicated by γH2AX and 8-hydroxy-2'-deoxyguanosine levels. Moreover, several DNA repair genes for homologous recombination (HR) and non-homologous end joining (NHEJ) were downregulated in EXCC/cisplatin compared to others. The addition of the GSH precursor N-acetylcysteine, which has ROS scavenging activity, attenuated all EXCC/cisplatin-induced changes. Notably, EXCC/cisplatin showed lower antiproliferation, apoptosis, ROS induction, GSH depletion, and γH2AX DNA damage in normal cells than in bladder cancer cells. Therefore, the co-treatment of EXCC/cisplatin reduces the proliferation of bladder cancer cells via oxidative stress-mediated mechanisms with normal cell safety.

The role of the transsulfuration pathway in spermatogenesis of vitamin D deficient mice

Vitamin D deficiency is a global health problem and has been linked to defective spermatogenesis and male infertility. In this study, we aimed to investigate the main enzymes involved in the transsulfuration pathway of 1-carbon metabolism, and spermatogenesis function. Therefore, sixteen male C57 mice were addressed to a control (standard diet) or vitamin D deficient (VDD) diet for 14 weeks. The results show that compared to the standard diet, VDD increased final body weight and reduced sperm quality, caused damage to the testicular structure, and decreased the serum levels of testosterone. In addition, serum concentrations of homocysteine, vitamin B12, and sperm oxidative stress markers increased. In testicular tissues, the CBS and CSE protein levels were down-regulated whereas HO-1 was up-regulated at both mRNA and protein expression levels. Within a mice deprivation model, VDD deeply suppressed testosterone and impaired spermatogenesis with oxidative stress-mediated mechanisms. The effects of the deprivation appeared to be at least in part independent of genomic and receptor-mediated vitamin D actions and suggest a specific impairment of the alternative transsulfuration pathway.

Opuntia ficus-indica (L.) Mill. - anticancer properties and phytochemicals: current trends and future perspectives.

Cancer is a leading cause of mortality worldwide, and conventional cancer therapies such as chemotherapy and radiotherapy often result in undesirable and adverse effects. Natural products have emerged as a promising alternative for cancer treatment, with comparatively fewer side effects reported. Opuntia ficus-indica (L.) Mill., a member of the Cactaceae family, contains a diverse array of phytochemicals, including flavonoids, polyphenols, betalains, and tannins, which have been shown to exhibit potent anticancer properties. Various parts of the Opuntia plant, including the fruits, stems/cladodes, and roots, have demonstrated cytotoxic effects against malignant cell lines in numerous studies. This review comprehensively summarizes the anticancer attributes of the phytochemicals found in Opuntia ficus-indica (L.) Mill., highlighting their potential as natural cancer prevention and treatment agents. Bibliometric metric analysis of PubMed and Scopus-retrieved data using VOSviewer as well as QDA analysis provide further insights and niche to be explored. Most anticancer studies on Opuntia ficus-indica and its purified metabolites are related to colorectal/colon cancer, followed by melanoma and breast cancer. Very little attention has been paid to leukemia, thyroid, endometrial, liver, and prostate cancer, and it could be considered an opportunity for researchers to explore O. ficus-indica and its metabolites against these cancers. The most notable mechanisms expressed and validated in those studies are apoptosis, cell cycle arrest (G0/G1 and G2/M), Bcl-2 modulation, antiproliferative, oxidative stress-mediated mechanisms, and cytochrome c. We have also observed that cladodes and fruits of O. ficus-indica have been more studied than other plant parts, which again opens the opportunity for the researchers to explore. Further, cell line-based studies dominated, and very few studies were related to animal-based experiments. The Zebrafish model is another platform to explore. However, it seems like more in-depth studies are required to ascertain clinical utility of this biosustainable resource O. ficus-indica.

SLC25A21 Suppresses Cell Growth in Bladder Cancer via an Oxidative Stress-Mediated Mechanism.

BackgroundBladder cancer (BCa) is a commonly diagnosed malignancy worldwide that has poor survival depending on its intrinsic biologic aggressiveness and a peculiar radio- and chemoresistance features. Gaining a better understanding of tumorigenesis and developing new diagnosis and treatment strategies for BCa is important for improving BCa clinical outcome. SLC25 family member 21 (SLC25A21), a carrier transporting C5-C7 oxodicarboxylates, has been reported to contribute to oxoadipate acidemia. However, the potential role of SLC25A21 in cancer remains absolutely unknown.MethodsThe expression levels of SLC25A21 in BCa and normal tissues were examined by real-time PCR and immunohistochemistry. Gain-of- and loss-of-function experiments were performed to detect the biological functions of SLC25A21 in vitro and in vivo by CCK-8 assay, plate colony formation assay, cell migration, invasion assay and experimental animal models. The subcellular distribution of substrate mediated by SLC25A21, mitochondrial membrane potential and ROS production were assessed to explore the potential mechanism of SLC25A21 in BCa.ResultsWe found that the expression of SLC25A21 was downregulated in BCa tissues compared to normal tissues. A significant positive correlation between decreased SLC25A21 expression and poor prognosis was observed in BCa patients. Overexpression of SLC25A21 significantly inhibited cell proliferation, migration and invasion and induced apoptosis in vitro. Moreover, the enhanced SLC25A21 expression significantly suppressed tumor growth in a xenograft mouse model. Furthermore, we revealed that SLC25A21 suppressed BCa growth by inducing the efflux of mitochondrial α-KG to the cytosol, decreasing to against oxidative stress, and activating the ROS-mediated mitochondrion-dependent apoptosis pathway.ConclusionsOur findings provide the first link between SLC25A21 expression and BCa and demonstrate that SLC25A21 acts as a crucial suppressor in BCa progression, which may help to provide new targets for BCa intervention.

Occupational exposure to gasoline in gasoline station male attendants promotes M1 polarization in macrophages.

Several studies have reported the toxicological implications of exposure to petroleum hydrocarbon fumes in animal models. There is little documentation on the effect of such exposure on oxidative stress levels and immune response. To our knowledge, no documentation of M1 polarization in macrophages in gasoline station male attendants. Therefore, this study aimed to evaluate the harmful effects of gasoline vapors in 62 male attendants (16-70 years) compared to 29 age- and sex-matched-unexposed controls. The attendants were recruited from Damietta governorate gasoline stations. Gasoline exposure induced a significant increase in tumor necrosis factor-α (TNF-α) level (p < 0.05) as well as a slight but non-significant increase in the activity of acidic mammalian chitinase (AMCase) (p > 0.05). Further TNF-α/AMCase ratio was significantly increased (p < 0.01) in sera of the attendants when compared to those of the healthy controls. Also, the total leucocytic and lymphocytic counts were significantly increased (p < 0.01 and p < 0.001, respectively). On contrary, neutrophils to lymphocytes ratio (NLR) and platelets to lymphocytes ratio (PLR) were significantly decreased (p < 0.05 and p < 0.001, respectively). In addition, significant reduction in hemoglobin (Hb) concentration, plasma glutathione reduced form (GSH), and catalase, as well as superoxide dismutase (SOD) activities in red blood cells were observed in the exposed attendants. As a result, malondialdehyde (MDA), nitric oxide (NO) levels, and NO/AMCase ratio were significantly increased (p < 0.05). In conclusion, this study inferred that prolonged gasoline exposure can mediate immune activation, especially M1 macrophages polarization, possibly via oxidative stress-mediated mechanism.

P–075 HAART exacerbates anti-Koch-induced reproductive toxicity via suppression of androgen and down-regulation of cGMP signaling

Abstract Study question Will highly active antiretroviral drugs (HAART) and antikochs impair reproductive function when used singly and concurrently? Summary answer HAART exacerbates antikoch-induced reproductive toxicity by stimulating testicular and penile oxido-inflammatory response. This was associated with suppression of androgen and down-regulation of cGMP signaling. What is known already Although the advent of HAART and antikochs has significantly improved the clinical status, life expectancy and quality of life of patients with HIV/tuberculosis, these drugs are with shortcomings. Studies have reported that HAART induces testicular toxicity and impairs sperm quality. Similarly, antikochs has been shown to trigger oxidative testicular and sperm damage. Available data have implicated HAART and antikoch in the pathogenesis of male infertility via oxidative stress-mediated mechanism. However, no study has reported the impact of the concurrent administration of both HAART and antikochs as seen in patients with TB/HIV co-infection on testicular function, sexual behaviour and fertility outcome. Study design, size, duration This is a prospective experimental study using animal model. Forty sexually mature inbred male Wistar rats of comparable age were used for the study. The study lasted 8 weeks. Participants/materials, setting, methods Animals were acclimatized for two weeks after which they were randomly allotted into four groups (n = 10). The control rats 0.5mL of distilled water as vehicle, anti-Koch-treated rats received a cocktail of anti-tuberculosis drugs (Rifampicin, Isoniazid, Pyrazinamide, and Ethambutol), HAART-treated animals received a cock-tail of antiretroviral drugs (Efavirenz, Lamivudine, and Tenofovir), while the HAART+antikochs-treated rats received treatment as HAART-treated as well as antikoch-treated. The doses of drugs used were the Human Equivalent doses for rats. Main results and the role of chance HAART exaggerated antikoch-induced increase in testicular lactate dehydrogenase activity, concentrations of lactate and uric acid, and reduced testicular sorbitol dehydrogenase activity. Furthermore, HAART worsens antikoch-induced decline in the activities of testicular and penile superoxide dismutase, catalase, glutathione peroxidase, and glutathione-S-transferase, as well as glutathione concentration, but increased malondialdehyde levels in testicular and penile tissues, as well as penile and testicular DNA fragmentation. Similarly, HAART aggravates antikoch-driven reduction in penile cGMP, circulatory and testicular testosterone, serum prolactin, LH and FSH, impaired sperm quality, sexual behaviour, and fertility outcome. Limitations, reasons for caution This is a prospective study using animal model; hence findings should be extrapolated to human with care. Human studies are thus recommended. Wider implications of the findings: This study demonstrates for the first time the impact of HAART and antikoch, when used singly or in combination, on sexual behaviour, sperm quality and penile and testicular integrity. The findings add to the available literature by providing the molecular mechanism through which HAART and/or antikoch possibly impair reproductive function. Trial registration number N/A

A monoterpene antioxidant, linalool, mitigates benzene-induced oxidative toxicities on hematology and liver of male rats

ABSTRACT Benzene is a volatile chemical implicated in leukemia and hepatic injury through oxidative stress-mediated mechanism. Linalool is a naturally small molecular monoterpene with proven antioxidant properties. This study was carried out to investigate the potential role of Linalool in ameliorating the oxidative stress-mediated hematologic and hepatic dysfunctions by Benzene in rats. Hepatic injury and hematological imbalance were induced in Wister rats by intravenous administration of 0.2 mL of benzene solution every other days for 3 consecutive weeks. Following benzene intoxication, 40 mg/kg linalool was post-administered each day orally for two weeks. Hematological alteration was assessed by comparing the hematological parameters of control and benzene-exposed animals with or without linalool supplementation. Plasmal activities of liver biomarker enzymes (ALT, AST, and ALP), total thiol and advanced oxidation protein products (AOPPs) along with hepatic activities of SOD, CAT, and hepatic contents of thiol-reduced glutathione (GSH), malondialdehyde, and percentage DNA fragment were measured. Linalool showed improvements in liver functions and restored altered hematology, decreased levels of AOPPs and oxidative stress and mitigated genotoxicity affected by benzene. In conclusion, linalool exerted its organ protective and myeloprotective effect through its influence on antioxidant defense system and reduction of oxidative stress.

HGF induces protective effects in α-naphthylisothiocyanate-induced intrahepatic cholestasis by counteracting oxidative stress

Cholestasis is a clinical syndrome common to a large number of hepatopathies, in which either bile production or its transit through the biliary tract is impaired due to functional or obstructive causes; the consequent intracellular retention of toxic biliary constituents generates parenchyma damage, largely via oxidative stress-mediated mechanisms. Hepatocyte growth factor (HGF) and its receptor c-Met represent one of the main systems for liver repair damage and defense against hepatotoxic factors, leading to an antioxidant and repair response. In this study, we evaluated the capability of HGF to counteract the damage caused by the model cholestatic agent, α-naphthyl isothiocyanate (ANIT). HGF had clear anti-cholestatic effects, as apparent from the improvement in both bile flow and liver function test. Histology examination revealed a significant reduction of injured areas. HGF also preserved the tight-junctional structure. These anticholestatic effects were associated with the induction of basolateral efflux ABC transporters, which facilitates extrusion of toxic biliary compounds and its further alternative depuration via urine. The biliary epithelium seems to have been also preserved, as suggested by normalization in serum GGT levels, CFTR expression and cholangyocyte primary cilium structure our results clearly show for the first time that HGF protects the liver from a cholestatic injury.

Platelet Oxidative Stress and its Relationship with Cardiovascular Diseases in Type 2 Diabetes Mellitus Patients.

Enhanced platelet activation and thrombosis are linked to various cardiovascular diseases (CVD). Among other mechanisms, oxidative stress seems to play a pivotal role in platelet hyperactivity. Indeed, upon stimulation by physiological agonists, human platelets generate and release several types of reactive oxygen species (ROS) such as O2 -, H2O2 or OH-, further amplifying the platelet activation response via various signalling pathways, including, formation of isoprostanes, Ca2+ mobilization and NO inactivation. Furthermore, excessive platelet ROS generation, incorporation of free radicals from environment and/or depletion of antioxidants induce pro-oxidant, pro-inflammatory and platelet hyperaggregability effects, leading to the incidence of cardiovascular events. Here, we review the current knowledge regarding the effect of oxidative stress on platelet signaling pathways and its implication in CVD such as type 2 diabetes mellitus. We also summarize the role of natural antioxidants included in vegetables, fruits and medicinal herbs in reducing platelet function via an oxidative stress-mediated mechanism.

Improvement of banana postharvest quality using a novel soybean protein isolate/cinnamaldehyde/zinc oxide bionanocomposite coating strategy

Soybean protein isolate (SPI) based coatings incorporating with plant-sourced cinnamaldehyde (CIN) or facile synthesized flower-like zinc oxide nanoparticle (ZnONP) have been used for the postharvest preservation of bananas. The effects of the pure SPI coating, SPI/CIN coating, and SPI/CIN/ZnONP nanocomposite coating on diverse physicochemical properties of bananas and antifungal performance were studied during the whole storage. Results demonstrated that SPI nanocomposite film could effectively delay ripening rate and weight loss of bananas. Compared with other SPI-based coating treatments, SPI/CIN/ZnONP nanocomposite coating could also hinder the harmful changes in fruit firmness, total soluble sugar, titratable acidity and sensory quality during the whole storage period. Moreover, the antifungal performance of SPI/CIN/ZnONP coating was 1.25-fold stronger than that of SPI/CIN treatment. This could be explained by the oxidative stress-mediated antifungal mechanism for CIN and ZnONP.

Astrocyte-produced carbon monoxide and the carbon monoxide donor CORM-A1 protect against cerebrovascular dysfunction caused by prolonged neonatal asphyxia.

Neonatal asphyxia leads to cerebrovascular disease and neurological complications via a mechanism that may involve oxidative stress. Carbon monoxide (CO) is an antioxidant messenger produced via a heme oxygenase (HO)-catalyzed reaction. Cortical astrocytes are the major cells in the brain that express constitutive HO-2 isoform. We tested the hypothesis that CO, produced by astrocytes, has cerebroprotective properties during neonatal asphyxia. We developed a survival model of prolonged asphyxia in newborn pigs that combines insults of severe hypoxia, hypercapnia, and acidosis while avoiding extreme hypotension and cerebral blood flow reduction. During the 60-min asphyxia, CO production by brain and astrocytes was continuously elevated. Excessive formation of reactive oxygen species during asphyxia/reventilation was potentiated by the HO inhibitor tin protoporphyrin, suggesting that endogenous CO has antioxidant effects. Cerebral vascular outcomes tested 24 and 48 h after asphyxia demonstrated the sustained impairment of cerebral vascular responses to astrocyte- and endothelium-specific vasodilators. Postasphyxia cerebral vascular dysfunction was aggravated in newborn pigs pretreated with tin protoporphyrin to inhibit brain HO/CO. The CO donor CO-releasing molecule-A1 (CORM-A1) reduced brain oxidative stress during asphyxia/reventilation and prevented postasphyxia cerebrovascular dysfunction. The antioxidant and antiapoptotic effects of HO/CO and CORM-A1 were confirmed in primary cultures of astrocytes from the neonatal pig brain exposed to glutamate excitotoxicity. Overall, prolonged neonatal asphyxia leads to neurovascular injury via an oxidative stress-mediated mechanism that is counteracted by an astrocyte-based constitutive antioxidant HO/CO system. We propose that gaseous CO or CO donors can be used as novel approaches for prevention of neonatal brain injury caused by prolonged asphyxia. NEW & NOTEWORTHY Asphyxia in newborn infants may lead to lifelong neurological disabilities. Using the model of prolonged asphyxia in newborn piglets, we propose novel antioxidant therapy based on systemic administration of low doses of a carbon monoxide donor that prevent loss of cerebral blood flow regulation and may improve the neurological outcome of asphyxia.

Abstract 845: Acute irradiation exposure induces long-term cardiac adverse effects in the spontaneously hypertensive rat

Abstract Radiation-induced heart disease (RIHD) presents a significant challenge in the oncology setting. For instance, patients receiving acute doses of irradiation to the thoracic cavity for Hodgkin's lymphoma or breast cancer are subject to an elevated risk of RIHD. Excessive oxidative stress, at least in part, is responsible for some of the tissue damage. The ability to monitor and mitigate the long-term cardiac effects of radiation exposure in these populations by modulating oxidative stress has the potential to lead to improved health outcomes. We utilized the spontaneously hypertensive rat (SHR), which has proven a good model for drug-induced cardiotoxicity, to evaluate irradiation-induced heart damage. SHRs were exposed to low, medium, or high doses of full-body irradiation. Necropsy was performed to collect serum and tissue samples at two and four weeks post-irradiation, as well as followed for one year. Four weeks following gamma irradiation, both males and females showed decreased heart mass and decreased whole body mass after exposure to medium and high doses of radiation and these decreases were sustained in the high dose groups after one year. Serum cardiac troponin I and T analysis revealed signs of cardiomyopathy in both the medium and high dose groups at early time points and this signal was sustained in some animals up to one year later. Echocardiography revealed functional changes in cardiac performance including an increase in left ventricular volume at diastole in males and a decrease in left ventricular mass. Low red blood cell count indicated sustained anemic conditions in both males and females receiving the highest dose of irradiation, yet males appeared to be more sensitive. Levels of pro-inflammatory IL-6 were elevated at four weeks in males receiving the high dose. Finally, multiple animals receiving radiation developed spontaneous tumors after one year. We are currently investigating the oxidative stress-mediated molecular mechanisms behind the radiation-induced cardiac damage. Citation Format: Elliot T. Rosen, Dmitry Kryndushkin, Baikuntha Aryal, Yanira Gonzalez, Leena Chehab, Jennifer Dickey, Steven Mog, V Ashutosh Rao. Acute irradiation exposure induces long-term cardiac adverse effects in the spontaneously hypertensive rat [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 845.

Minocycline induces apoptosis in acute lymphoblastic leukemia Jurkat cells

Acute lymphoblastic leukemia (ALL) is still an incurable hematologic malignant disorder. Therefore, novel therapeutic approaches are urgently required. In this study, we tested the pro-apoptotic properties of minocycline (Mino) in human peripheral blood lymphocyte cells (hPBLCs) and Jurkat cells (clone E6-1). hPBLCs and Jurkat cells were exposed to increasing concentrations of minocycline (Mino; 10–200 μM). We found that Mino induces apoptosis in Jurkat cells through an H2O2-mediated signaling pathway. Indeed, H2O2 serves as a signaling molecule, thus triggering a molecular cascade involving the oxidation of the DJ-1 cysteine106-thiol residue into DJ-1 cysteine106-sulfonic acid; activation of transcription factors NF-kappaB, P53 and c-JUN; up-regulation of pro-apoptotic proteins BAX/PUMA and proteins involved in the maintenance of mitochondrial function PINK1/PARKIN; and loss of mitochondrial membrane potential and activation of CASPASE-3/AIF, which are responsible for nuclear fragmentation, demonstrated by fluorescence microscopy, flow cytometry and Western blot analysis. Interestingly, Mino induced none of the aforementioned oxidative stress and/or apoptosis markers in hPBLCs. We report for the first time that minocycline, a second-generation, semi-synthetic tetracycline derivative, selectively induces apoptosis in Jurkat cells through an oxidative stress-mediated mechanism. Additionally, since Mino has well-established clinical pharmacokinetic and pharmacodynamic properties, we propose that this tetracycline is a promising anti-leukemic drug against ALL.

Antioxidant and Cerebroprotective Roles of Carbon Monoxide (CO) Against Cerebrovascular Injury Caused by Prolonged Neonatal Asphyxia

Asphyxia occurring in the fetus and newborn infant frequently leads to hypoxic‐ischemic encephalopathy (HIE) in survivors. The neonatal brain circulatory system is compromised by asphyxia/reventilation via a mechanism that may involve oxidative stress. CO, a gaseous messenger with antioxidant properties, is produced from heme via the heme oxygenase (HO)‐catalyzed reaction. We tested the hypothesis that CO, either produced by the brain, or delivered systemically by the donor molecule CORM‐A1, has a cerebrovascular protective role during neonatal asphyxia. We developed a novel survival model of prolonged asphyxia (50 – 60 min) in newborn pigs that combines insults of severe hypoxia (PaO2, 20–30 mm Hg), hypercapnia (PaCO2, 70–80 mm Hg), and acidosis (pH, 6.9–7.0) while avoiding extreme systemic hypotension and cerebral ischemia. During the asphyxia conditions, we observed immediate and sustained activation of brain HO as detected by an elevated CO concentration in the cortical periarachnoid fluid. Cortical astrocytes are among the main sources of brain CO production in normal and asphyxiated brains. Asphyxia followed by a 60‐min reventilation with room air caused excessive formation of reactive oxygen species (ROS) in the neonatal brain. Brain oxidative stress was potentiated by the HO inhibitor tin protoporphyrin, suggesting that activation of astrocytic HO/CO during asphyxia has antioxidant effects. Administered 30 min before asphyxia, CORM‐A1 (2 mg/kg i.p.) prevented excessive ROS formation in the brain during reventilation. We tested the effects of prolonged neonatal asphyxia on cerebral vascular dilator functions after 24 and 48 h of recovery using the cranial window technique. Endothelium‐dependent vasodilatory responses to hypercapnia and bradykinin were not negatively affected by prolonged asphyxia. In contrast, astrocyte‐dependent cerebral vasodilatory responses to adenosine diphosphate (ADP) and glutamate were compromised, indicating that astrocytes are selectively injured by prolonged asphyxia. Endothelium‐ and astrocyte‐independent cerebral vascular smooth muscle functions tested by vasodilations to isoproterenol and sodium nitroprusside remained intact in post‐asphyxic newborn pigs. In CORM‐A1‐pretreated animals, prolonged asphyxia did not produce any cerebral vascular incapacities, suggesting that CO therapy protects astrocytes from asphyxia/reventilation injury. Overall, prolonged neonatal asphyxia without systemic hypotension or cerebral ischemia injures cortical astrocytes via an oxidative stress‐mediated mechanism that can be partially counteracted by activation of the endogenous HO/CO‐based antioxidant system in the brain or by CO/CORM‐A1 therapy. We propose that gaseous CO and CO donor molecules can be used as novel efficient therapeutic approaches to prevention of neonatal brain injury caused by prolonged asphyxia.Support or Funding InformationR01 NS 101717; R01 HL 034059; R01 HL 042851This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Oxidative stress and response of antioxidant system in Nostoc muscorum exposed to different forms of Zinc

Abstract Objective Present study aims to evaluate oxidative stress-mediated toxicity mechanisms of nano-ZnO (N-ZnO) compared to ZnCl2 and bulk-ZnO (M-ZnO), using cyanobacterium as a toxicity assessment tool. Methods Nostoc muscorum was used as a test organism and the experiments were performed in parallels after treated with 2–128 μM of N-ZnO, M-ZnO, and ZnCl2. Results Low concentrations of ZnCl2 (2–8 μM) and N-ZnO (16–32 μM) led to a significant increase in the carotenoids, which could be ascribed to its role as an antioxidant, whereas higher concentrations were inhibitory to the photosynthetic pigments. Enhanced activities of superoxide dismutase (SOD), peroxidase (POD) and accelerated lipid peroxidation depicted significant accumulation of superoxide and peroxide radicals in N. muscorum exposed to N-ZnO and ZnCl2. The non-enzymatic antioxidants such as proline and total phenols also showed enhanced accumulations up to 16 and 64 μM of ZnCl2 and N-ZnO treatment, respectively. Conclusion Our results for the very first time depicted the significant accumulation of stress biomarkers in N. muscorum in response to deleterious effects of oxidative stress caused by N-ZnO, ZnCl2, and M-ZnO. Present results revealed varying levels of toxicity of various forms of zinc, which decreased in an order of ZnCl2&gt;N-ZnO&gt;M-ZnO.

PP.02.23] NATURAL ANTIOXIDANT ICE-CREAM ACUTELY REDUCES BLOOD PRESSURE AND IMPROVES VASCULAR FUNCTION IN PATIENTS WITH METABOLIC SYNDROME

Objective: Epidemiological investigations revealed an inverse correlation between the intake of polyphenols-containing foods and coronary artery disease mortality. A large number of studies has investigated the possible blood pressure (BP) lowering effect of different dietary supplements. We hypothesized that a natural antioxidant ice cream, product with a selected blend of cocoa, hazelnut and other ingredients from organic farming, could improve vascular function and decrease blood pressure in sample of patients with metabolic syndrome via an oxidative stress-mediated mechanism. Design and method: We performed a single blind crossover study in which we measured the acute effect of natural antioxidant ice cream, on vascular function and blood pressure in a population of patient with metabolic syndrome. 10 subjects (5 male, 5 female), mean age 56 years, were randomly allocated to a treatment sequence with 100 mg of antioxidant ice cream or milk ice cream in a cross-over, single-blind design. Total polyphenol content (mg/100 g) was significantly higher in antioxidant ice cream compared to milk ice cream (control (1817 vs 96). There was at least 1 week washout between the 2 phases of the study. Oxidative stress (assessed by measuring plasma hydroperoxides, analytic method dROMs), Nitric oxide (NO) bioavailability (NOx), vascular function (flow mediated dilatation, FMD) and blood pressure were assessed at baseline, after a 24 hours abstinence from food rich in polyphenols, and 2 hours after ingestion of ice cream. Results: Serum polyphenols (139,28 ± 28,32 vs 288,57 ± 58,12. p < 0.001), NOx (23,34 ± 5,24 vs 48,24 ± 8,66 .p < 0.001), FMD (2,34 ± 1,46 vs 6,43 ± 1,86 .p < 0.001) increased significantly, oxidative stress (D-Roms 426,27 ± 49,03 vs 378,85 ± 38,12. p < 0.01;), and systolic (−7,17 ± 4,67 mm/Hg. p < 0.001) and diastolic (−5,48 ± 3,92 mm/Hg. p < 0.001)blood pressure decreased only after antioxidant ice cream ingestion. No changes were found after control ice cream ingestion. Conclusions: For the first time, a natural antioxidant ice cream rich in polyphenols was demonstrated to acutely improve vascular function and decrease blood pressure in patients with metabolic syndrome through a reduction of oxidative stress and increase of NO bioavailability. This may be a novel valuable strategy for BP lowering in the high-normal range in which current hypertension management guidelines do not recommend drug treatment.

Calcium and oxidative stress mediate perillaldehyde-induced apoptosis in Candida albicans.

New anti-Candida albicans drugs are needed due to the emergence of resistant cases in recent years. Perillaldehyde (PAE) is a natural monoterpenoid compound derived from Perilla frutescens. The minimum inhibitory concentration of PAE against C. albicans was 0.4μL/mL. We aimed to elucidate the antifungal mode of action of PAE against C. albicans. The antifungal activity of PAE against C. albicans was found to correlate with an elevation in intracellular Ca2+ and accumulation of ROS. Several downstream apoptosis events such as the disruption of mitochondrial membrane potential, phosphatidylserine externalization, cytochrome c release, and metacaspase activation were observed in PAE-treated cells. DNA damage and nuclear fragmentation assays also revealed apoptosis of C. albicans cells. In summary, by means of fluorescent microscopy, flow cytometer analysis, and Western blot, our data uncovered that PAE exerts its antifungal activity through Ca2+ and oxidative stress-mediated apoptosis mechanisms. This study deciphered the mode of action of PAE, which will be useful in the design of improved antifungal therapies.

Benzophenones and xanthone derivatives from Garcinia schomburgkiana-induced P-glycoprotein overexpression in human colorectal Caco-2 cells via oxidative stress-mediated mechanisms

BackgroundUp-regulation of P-gp is an adaptive survival mechanism of cancer cells from chemotherapy. Three new phytochemicals including two benzophenones, guttiferone K (GK) and oblongifolin C (OC), and a xanthone, isojacaruebin (ISO), are potential anti-cancer agents. However, the capability of these compounds to increase multidrug-resistance (MDR) through P-gp up-regulation in cancer cells has not been reported. PurposeThis study was to investigate the effects of GK, OC and ISO on P-gp up-regulation in colorectal adenocarcinoma cells (Caco-2 cells). In addition, the mechanisms underlying their inductive effect were also determined. MethodsThe inductive effect of GK, OC and ISO on P-gp expression at transcription level was measured by real-time reverse transcription polymerase chain reaction. The reactive oxygen species production was determined by 2′, 7′-dichlorofluorescin diacetate assay. The protein content of P-gp and involvement of mitogen-activated protein kinases (MAPK) pathway was evaluated by western blot analysis. ResultsGK, OC and ISO (50 µM, 24 h) were able to increase the amount of MDR1 mRNA and protein in Caco-2 cells. The presence of N-acetyl-l-cysteine significantly prevented the inductive effect of GK, OC and ISO on MDR1 mRNA level. Moreover, MAPK inhibitors including U0126 (an ERK1/2/MAPK inhibitor) and SB202190 (p38/MAPK inhibitor) suppressed an increase of MDR1 mRNA levels in the cells treated with benzophenones (GK, OC) and xanthone ISO, respectively. These findings were in agreement with the increase of phosphorylated form of either ERK1/2 (p-ERK1/2) or p38 (p-p38) upon treatment of the cells with these three compounds. In addition, OC and ISO, but not GK, increased mRNA of c-Jun level. ConclusionThe benzophenones GK, OC and xanthone ISO are likely MDR inducers through up-regulation of P-gp expression at transcription level. Their molecular mechanisms involve oxidative stress-mediated activation of MAPK signaling pathway.

Abstract 3328: Mitigating long-term cardiac adverse effects of radiation exposure: Emerging opportunities in protein oxidation and autophagy modulation

Abstract Radiation-induced heart disease (RIHD) presents a significant challenge in the oncology setting. Patients who receive acute doses of irradiation to the thoracic cavity for Hodgkin's Lymphoma and breast cancer are subject to an elevated risk of RIHD. The ability to mitigate the long-term cardiac effects of radiation exposure in these populations by modulating protein oxidation and the process of autophagy in the heart has the potential to lead to improved health outcomes. We utilized the spontaneously hypertensive rat (SHR), which has proven a good model for drug-induced cardiotoxicity, to evaluate radiation-induced heart disease. SHRs were exposed to low, medium, or high doses of full-body irradiation. Necropsy was performed to collect serum and tissue samples at various time points up to one year. Echocardiography and electrocardiography were performed to evaluate functional changes in cardiac performance. Four weeks following ionizing radiation, both males and females showed decreased heart mass and decreased whole body mass in the groups exposed to medium and high doses of radiation. A marked difference in both heart and whole body mass was observed in the high dose group after one year. Anemic conditions were noted by low red blood cell counts observed in both males and females at all three time points in the animals receiving the highest dose of irradiation. Cardiac troponin T analysis revealed cardiotoxicity in both the medium and high dose groups at early time points. Echocardiography revealed that left ventricular volume at diastole was increased in males following high dose irradiation, and that left ventricular mass decreased following high irradiation exposures. Finally, it should also be noted that after one year, multiple animals receiving radiation developed spontaneous tumors. We are currently exploring the oxidative stress-mediated molecular mechanisms behind the radiation-induced cardiac damage and the subsequent, protective autophagic response. Citation Format: Elliot T. Rosen, Dmitry Kryndushkin, Yanira Gonzalez, Baikuntha Aryal, Leena Chehab, Jennifer Dickey, Ashutosh Rao. Mitigating long-term cardiac adverse effects of radiation exposure: Emerging opportunities in protein oxidation and autophagy modulation. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3328. doi:10.1158/1538-7445.AM2015-3328