• Parasites, Hosts and Diseases
• /
• 제56권1호
• /
• pp.1-9
• /
• 2018

Giardia lamblia, an anaerobic, amitochondriate protozoan parasite causes parasitic infection giardiasis in children and young adults. It produces pyruvate, a major metabolic product for its fermentative metabolism. The current study was undertaken to explore the effects of pyruvate as a physiological antioxidant during oxidative stress in Giardia by cysteine-ascorbate deprivation and further investigation upon the hypothesis that oxidative stress due to metabolism was the reason behind the cytotoxicity. We have estimated intracellular reactive oxygen species generation due to cysteine-ascorbate deprivation in Giardia. In the present study, we have examined the effects of extracellular addition of pyruvate, during oxidative stress generated from cysteine-ascorbate deprivation in culture media on DNA damage in Giardia. The intracellular pyruvate concentrations at several time points were measured in the trophozoites during stress. Trophozoites viability under cysteine-ascorbate deprived (CAD) medium in presence and absence of extracellular pyruvate has also been measured. The exogenous addition of a physiologically relevant concentration of pyruvate to trophozoites suspension was shown to attenuate the rate of ROS generation. We have demonstrated that Giardia protects itself from destructive consequences of ROS by maintaining the intracellular pyruvate concentration. Pyruvate recovers Giardia trophozoites from oxidative stress by decreasing the number of DNA breaks that might favor DNA repair.

• Asian Pacific Journal of Cancer Prevention
• /
• 제16권13호
• /
• pp.5343-5348
• /
• 2015

Promoter hypermethylation of the runt-related transcription factor 3 (RUNX3) gene is associated with increased risk of hepatocellular carcinoma (HCC). Oxidative stress plays a vital role in both carcinogenesis and progression of HCC. However, whether oxidative stress and RUNX3 hypermethylation in HCC have a cause-and-effect relationship is not known. In this study, plasma protein carbonyl and total antioxidant capacity (TAC) in patients with hepatitis B virus (HBV)-associated HCC (n=60) and age-matched healthy subjects (n=80) was determined. RUNX3 methylation in peripheral blood mononuclear cells (PBMC) of subjects was measured by methylation-specific PCR. Effect of reactive oxygen species (ROS) on induction of RUNX3 hypermethylation in HCC cells was investigated. Plasma protein carbonyl content was significantly higher, whereas plasma TAC was significantly lower, in HCC patients than healthy controls. Based on logistic regression, increased plasma protein carbonyl and decreased plasma TAC were independently associated with increased risk for HCC. PBMC RUNX3 methylation in the patient group was significantly greater than in the healthy group. RUNX3 methylation in hydrogen peroxide ($H_2O_2$)-treated HepG2 cells was significantly higher than in untreated control cells. In conclusion, increase in oxidative stress in Thai patients with HBV-associated HCC was demonstrated. This oxidative increment was independently associated with an increased risk for HCC development. RUNX3 in PBMC was found to be hypermethylated in the HCC patients. In vitro, RUNX3 hypermethylation was experimentally induced by $H_2O_2$. Our findings suggest that oxidative stress is a cause of RUNX3 promoter hypermethylation in HCC cells.

• 농업과학연구
• /
• 제46권3호
• /
• pp.427-437
• /
• 2019

Oxidative stress and overproduction of free radicals have been reported to be a major pathological hallmark of neurodegenerative diseases. Samultang has been known as a beneficial agent to treat liver disease and cardiovascular diseases. However, the anti-oxidant activities and neuro-protective effects of Samultang against oxidative stress still have not been evaluated yet. The aim of the present study was to investigate the anti-oxidant and protective effects of Samultang and its four herbal plants, Paeonia lactiflora (PL), Ligusticum striatum (LS), Rehmannia glutinosa (RG), and Angelica gigas (AG), in vitro system and in SH-SY5Y neuronal cells. The extracts of Samultang strongly increased the radical scavenging activities of 1,1-diphenyl-2-picrylhydrazyl (DPPH), hydroxyl radical (${\cdot}OH$), and nitric oxide (NO) in a concentration-dependent manner. Furthermore, we investigated the protective effects of Samultang on cellular damage against oxidative stress induced by hydrogen peroxide ($H_2O_2$) in SH-SY5Y cells. Treatment with Samultang alleviated the oxidative stress from $H_2O_2$ by increasing the cell viability and decreasing the intracellular reactive oxygen species levels. Based on these results, we further investigated the radical scavenging effects of PL, LS, RG, and AG. In our results, PL had the highest DPPH, ${\cdot}OH$, and NO radical scavenging activities. Thus, PL has a crucial role in Samultang, which has anti-oxidative and neuro-protective effects. The present research suggests that Samultang and PL have protective roles against oxidative stress from $H_2O_2$-induced neuronal cell death.

• The Korean Journal of Physiology and Pharmacology
• /
• 제2권4호
• /
• pp.427-433
• /
• 1998

In brain hypoxic-ischemia, an excess release of glutamate and a marked production of reactive oxygen species (ROS) occur in neuronal and non-neuronal cells. The present study investigated the effect of the biological antioxidants dihydrolipoic acid (DHLA) and lipoic acid (LA) on N-methyl-D-aspartate (NMDA)- and ROS-induced neurotoxicity in cultured rat cortical neurons. DHLA enhanced NMDA-evoked rises in intracellular calcium concentration ($[Ca^{2+}]_i$). In contrast, LA did not alter the NMDA-evoked calcium responses but decreased after a brief treatment of dithiothreitol (DTT), which possesses a strong reducing potential. Despite the modulation of NMDA receptor-mediated rises in $[Ca^{2+}]_i$, neither DHLA nor LA altered the NMDA receptor-mediated neurotoxicity, as assessed by measuring the amount of lactate dehydrogenase released from dead or injured cells. DHLA, but not LA, prevented the neurotoxicity induced by xanthine/xanthine oxidase-generated superoxide radicals. Both DHLA and LA decreased the glutathione depletion-induced neurotoxicity. The present data may indicate that biological antioxidants DHLA and LA protect neurons from ischemic injuries via scavenging oxygen free radicals rather than modulating the redox modulatory site(s) of NMDA receptor.

• 대한한방내과학회지
• /
• 제26권2호
• /
• pp.379-389
• /
• 2005

Objectives: It is well known that aging and aging-related diseases are linked to the increased level of oxidative stress caused by reactive oxygen species(ROS) and reactive nitrogen species(RNS). Nonprotein-SH decreases during aging, while substances such as ROS, nitric oxide(NO), peroxynitrite($ONOO^-$), myeloperoxidase(MPO), and dityrosine show a significant increase. This study investigated the effect of Ichungwhan on the aging process by examining its effect on the generation of the above-mentioned substances. Methods: Four comparison groups of SD rats were used. They were 6 month-old rats, 24 month-old rats, and 24 month-old rats fed with food containing 0.1% and 0.3% of Ichungwhan extract. The amount of NO, $ONOO^-$, and ROS in the rats' kidneys were examined using a fluorescence microplate reader. The reagents used for this purpose include: dihydrorhodamine 123 (DHR 123), 2',7' -dichlorodihydrofluorescein, diacetate(DCFDA), and 4,5-diaminofluorescein(DAF-2). A spectrophotometer was used to investigate the reactivity of nonprotein-SH and myeioperoxidase(MPO), using reagents such as trichloroacetic acid(TCA) and tetramethylbenzidine(TMB). The amounts of MPO protein and dityrosine were measued by western blot. Results: The observed effects of Ichungwhan on rats were as follows: increase of nonprotein-SH; effective decrease of RNS level by suppression of the generation system of $ONOO^-$ and NO; decrease of ROS level; decrease of the MPO reactivity and the subsequent reduction of amount of MPO protein; retardation of dityrosine formation. It can be hypothesized, therefore, that Ichungwhan affects both the earlier and later phases of the molecular inflammatory process, and retards the aging process. Conclusions: Empirical evidence in this study supports a role for Ichungwhan in generation mechanisms of aging process-linked substances ROS, NO, $ONOO^-$, nonprotein-SH, MPO and dityrosine. Affects contrary to the aging process observed in rats beg further empiricism to investigate potential application of Ichungwhan as a medication for age-related diseases in humans.

• Journal of Acupuncture Research
• /
• 제31권4호
• /
• pp.33-43
• /
• 2014

This study was performed to investigate the protective effects of acupuncture on the liver in the oxidative stress caused by cadmium accumulation. Sprague-Dawley male($150{\pm}30g$) rats were stabilized for a week and divided into 5 groups which is normal, control, $LR_3$ acupuncture, $BL_{23}$ acupuncture and sham acupuncture group. For three days experimental groups were received oral doses of cadmium 2 mg/kg twice a day. Acupuncture was given bilaterally at each point 10 times for two weeks. The depth of stimulation was 1 mm at right angles and torsion of acupuncture was produced 2 times per second for 1 minutes. The liver was shipped off and taken weight at the last day of two weeks, and hepatic functions was confirmed through alanine transaminase(ALT) and aspartate amino-transferase(AST). We measured reactive oxygen species of serum, liver and kidney, and compared expression levels of superoxide dismutase(SOD), catalase, glutathione peroxidase(Gpx), nuclear factor erythroid derived 2-related factor 2(Nrf-2), heme oxygenase-1(HO-1), nuclear factor-${\kappa}B$ (NF-${\kappa}B$), cyclooxygenase-2(COX-2), inducible nitric oxide synthase(iNOS), Bax and Cytochrome c. $BL_{23}$ acupuncture group significantly increased liver weight and decreased ALT compared to control group. For the oxidative stress, $LR_3$ acupuncture group significantly reduced reactive oxygen species, and $BL_{23}$ acupuncture group significantly reduced reactive oxygen species and inflammation-related protein compared to control group. But $LR_3$ acupuncture group and $BL_{23}$ acupuncture group didn't significantly reduce apoptosis-related protein. Therefore $LR_3$ and $BL_{23}$ acupuncture showed the effects of antioxidant and anti-inflammatory, especially $BL_{23}$ acupuncture was more effective than $LR_3$ acupuncture on the protection of liver in the oxidative stress.

• Biomolecules & Therapeutics
• /
• 제20권1호
• /
• pp.68-74
• /
• 2012

Anthocyanins have received growing attention as dietary antioxidants for the prevention of oxidative damage. Astrocytes, which are specialized glial cells, exert numerous essential, complex functions in both healthy and diseased central nervous system (CNS) through a process known as reactive astrogilosis. Therefore, the maintenance of glial cell viability may be important because of its role as a key modulator of neuropathological events. The aim of this study was to investigate the effect of anthocyanin on the survival of glial cells exposed to oxidative stress. Our results demonstrated that anthocyanin extracts from black soybean increased survival of U87 glioma cells in a dose dependent manner upon oxygen-glucose deprivation (OGD), accompanied by decrease levels of reactive oxygen species (ROS). While treatment cells with anthocyanin extracts or OGD stress individually activated autophagy induction, the effect was signifi cantly augmented by pretreatment cells with anthocyanin extracts prior to OGD. The contribution of autophagy induction to the protective effects of anthocyanin was verifi ed by the observation that silencing the Atg5 expression, an essential regulator of autophagy induction, reversed the cytoprotective effect of anthocyanin extracts against OGD stress. Treatment of U87 cells with rapamycin, an autophagy inducer, increased cell survival upon OGD stress comparable to anthocyanin, indicating that autophagy functions as a survival mechanism against oxidative stress-induced cytotoxicity in glial cells. Our results, therefore, provide a rationale for the use of anthocyanin as a preventive agent for brain dysfunction caused by oxidative damage, such as a stroke.

• 한국독성학회:학술대회논문집
• /
• 한국독성학회 2002년도 Current Trends in Toxicological Sciences
• /
• pp.93-93
• /
• 2002

Oxidative stress has been associated with a number of diseases in humans. Among the sources that can generate oxidative stress, it has been reported that iron can generate reactive oxygen species (ROS) with thiol. In iron overload state, increased thiol levels in plasma appeared to be associated with human mortality.(omitted)

• 한국독성학회:학술대회논문집
• /
• 한국독성학회 2002년도 Current Trends in Toxicological Sciences
• /
• pp.94-94
• /
• 2002

Oxidative stress induced by reactive oxygen and/or nitrogen species has been considered as a major cause of cellular injuries in a variety of neurodegenerative disorders including Alzheimer's disease (AD). Inflammatory as well as oxidative tissue damage has been implicated in pathophysiology of AD, and non-steroidal anti-inflammatory drugs have been reported to have beneficial effects in the treatment or prevention of AD.(omitted)

• 대한약학회:학술대회논문집
• /
• 대한약학회 2002년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2
• /
• pp.290.1-290.1
• /
• 2002

The surgically ovariectomized rat induces aging by reactive oxyyen species(ROS) generation. Free oxygen radicals have been proposed as important causative agents of aging. The purpose of this study was to investigate the effect of Chondroitin Sulfate(CS) to prevent ovariectomy(OVX) induced oxidative stress and atherosclerosis. The OVX rats were given intraperitoneally CS at dose of 100mg/kg and 200mg/kg daily for fifteen weeks. (omitted)