• Journal of Veterinary Clinics
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• v.36 no.2
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• pp.102-105
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• 2019

Nitrotyrosine was found to be dependent on the severity of myxomatous mitral valve disease (MMVD). However, a correlation of serum nitrotyrosine concentration in dogs with MMVD and the progression of the disease has not been investigated. This study compared changes in serum nitrotyrosine concentration with the progression of MMVD. Nine client-owned dogs were recruited for the study. Dogs were classified by measuring the amount of regurgitation using echocardiography into mild, moderate, or severe MMVD groups. Serum nitrotyrosine concentration was measured by an enzyme-linked immunosorbent assay test. Serum nitrotyrosine concentration was significantly higher at 180 days than at 0 day (P < 0.05). However, serum nitrotyrosine concentration at 360 days was lower than that at 180 days (P < 0.05). Serum nitrotyrosine concentration at 540 days was lower than at 180 days (P < 0.05). There was no correlation between serum nitrotyrosine and left atrial to aortic root diameter ratio (LA/Ao ratio) (n = 33, $R^2=0.003$, P = 0.759). Also, there was no correlation between serum nitrotyrosine and vertebral heart score (VHS) (n = 33, $R^2=0.026$, P = 0.368) and left ventricular end-diastolic diameter, normalized for body weight by the formula (LVEDDN) (n = 33, $R^2=0.053$, P = 0.196). The results of the study suggest that the progression of MMVD is correlated with changes in serum nitrotyrosine concentration, which shows potential for use as a cardiac biomarker which can be used to analyze the progression of disease in MMVD.

• Korean Journal of Veterinary Research
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• v.57 no.1
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• pp.17-21
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• 2017

The aim of this study was to compare serum nitrotyrosine concentrations in healthy dogs with those in dogs with myxomatous mitral valve disease (MMVD). Fifty client-owned dogs were included in this study. Based on echocardiographic results, dogs were categorized into healthy (control), mild-, moderate-, and severe-MMVD groups. Serum nitrotyrosine concentrations were determined from enzyme-linked immunosorbent assays. No significant difference between control dogs and dogs with mild MMVD was detected (p = 0.31). However, dogs with moderate MMVD had significantly higher serum concentrations of nitrotyrosine (p = 0.04) than that in controls, and dogs with severe MMVD had significantly lower serum concentrations of nitrotyrosine (p = 0.03) than that in moderate MMVD dogs. There were negative correlations in the association of serum nitrotyrosine with age (n = 30, $R^2=0.067$, p = 0.27), left atrial-to-aortic root diameter ratio (n = 30, $R^2=0.02$, p = 0.57), and platelet count (n = 30, $R^2=0.39$, p = 0.003); however, only the platelet correlation was significant. Among dogs with MMVD, there was no significant difference in serum nitrotyrosine concentration between males and females. The results of this study suggest that tyrosine nitration end-products might be potential biomarkers for the detection of MMVD in dogs.

• BMB Reports
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• v.38 no.5
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• pp.577-583
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• 2005

Subtilisin QK, which is newly identified as a fibrinolytic enzyme from Bacillus subtilis QK02, has the ability of preventing nitrotyrosine formation in bovine serum albumin induced by nitrite, hydrogen peroxide and hemoglobin in vitro verified by ELISA, Western-blot and spectrophotometer assay. Subtilisin QK also attenuates the fluorescence emission spectra of bovine serum albumin in the course of oxidation caused by nitrite, hydrogen peroxide and hemoglobin. Furthermore, subtilisin QK could suppress the transformation of oxy-hemoglobin to met-hemoglobin caused by sodium nitrite, but not the heat-treated subtilisn QK. Compared with some other fibrinolytic enzymes and inactivated subtilisin QK treated by phenylmethylsulfonylfluoride, the ability of inhibiting met-hemoglobin formation of subtilisin QK reveals that the anti-oxidative ability of subtilisin QK is not concerned with its fibrinolytic function. Additionally, nitrotyrosine formation in proteins from brain, heart, liver, kidney, and muscle of mice that is intramuscular injected the mixture of nitrite, hydrogen peroxide and hemoglobin is attenuated by subtilisin QK. Subtilisin QK can also protect Human umbilical vein endothelial cell (ECV-304) from the damage caused by nitrite and hydrogen peroxide.

• The Korea Journal of Herbology
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• v.36 no.1
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• pp.1-8
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• 2021

Objective : Citri Unshius Pericarpium (Citrus unshiu peel) has been used in Korean medicine to treat indigestion, vomiting, coughing and phlegm. This study investigated the hepatoprotective effect of ethanol extract of Citrus unshiu peel (CEE) in cadmium (CdCl2)-treated mouse model. Methods : CEE was dissolved in water and administered orally to mice once a day for 7 consecutive days. The mice were then exposed to a single intraperitoneal (i.p.) injection of cadmium (4 mg/kg body weight) to induce acute hepatotoxicity. At the end of the experiment, blood and liver tissue samples were collected, analyzed for alanine aminotransferase (ALT), aspartate aminotransferase (AST), and histopathological evaluation. Liver damage was assessed as the percentage of degenerative areas of the hepatic parenchyma, the number of degenerative hepatocytes, and the number of infiltrated inflammatory cells. Results : In cadmium-treated rats, pretreatment with CEE significantly reduced the serum ALT and AST levels associated with liver damage. Histopathologically, CEE prevented degenerative changes on the hepatic tissues including confluent necrosis, congestions and infiltration of inflammatory cells. CEE also reduced the elevation of oxidative stress markers (nitrotyrosine and 4-hydroxynonenal) and apoptosis markers (cleaved caspase-3 and cleaved PARP) positive cells. PARP protein expression in liver tissue was also restored by CEE. Conclusion : This study showed that CEE exerted antioxidant and anti-apoptotic effects against cadmium-induced liver injury. Thus, it can be concluded that CEE can be used to prevent liver damage caused by cadmium.

• The Journal of Korean Medicine
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• v.23 no.4
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• pp.55-63
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• 2002

Objectives: Peroxynitrite ($ONOO^{-}$), formed from the reaction of superoxide <${\cdot}O_2^{-}$) and nitric oxide (NO), is a cytotoxic species that can oxidize several cellular components such as proteins, lipids and DNA. It has been implicated in diseases such as aging process, Alzheimer's disease, rheumatoid arthritis, cancer and arteriosclerosis. Due to the lack of endogenous enzymes responsible for $ONOO^{-}$ inactivation, developing a specific $ONOO^{-}$ scavenger is of considerable importance. The aim of this study was to evaluate $ONOO^{-}$ scavenging activity and its mechanism in Cheonga-hwan (CAH). Methods: The $ONOO^{-}$ scavenging activity in CAH was assayed by measuring oxidized dihydrorhodamine 123 (DHR 123) by fluorescence. The scavenging efficacy was expressed as $IC_{50}$, showing the concentration of each sample required to cause 50% inhibition of DHR 123 oxidation. In a separate study, the protective effect of CAR on $ONOO^{-}$-induced nitration of bovine serum albumin (BSA) was investigated using immunoassay with a monoclonal anti-nitrotyrosine antibody, and a horseradish peroxidase-conjugated anti-mouse secondary antibody from sheep. Results: CAH showed potent scavenging activities of $ONOO^{-}$, NO and ${\cdot}O_2^{-}$. The data demonstrated that CAH led to decreased $ONOO^{-}$-mediated nitration of tyrosine through electron donation. CAH showed significant inhibition on nitration of bovine serum albumin by $ONOO^{-}$ in a dose-dependent manner. Conclusions: CAH can be developed as an effective peroxynitrite scavenger for the prevention of the $ONOO^{-}$ involved diseases.

• The Korean Journal of Physiology and Pharmacology
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• v.3 no.4
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• pp.375-382
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• 1999

Growing evidence indicates that enhanced generation or actions of nitric oxide (NO) are implicated in the pathogenesis of hypertension in spontaneously hypertensive rats and diabetic nephropathy in streptozotocin (STZ)-induced diabetic rats. We investigated whether inducible nitric oxide synthase (iNOS) expression in STZ-induced diabetic rats is responsible for the alterations of vascular reactivity. Diabetic state was confirmed 28 days after injection of STZ (i.p) in rats by measuring blood glucose. In order to evaluate whether short term (4 weeks) diabetic state is related with altered vascular reactivity caused by iNOS expression, isometric tension experiments were performed. In addition, plasma nitrite/nitrate (NOx) levels and expression of iNOS in the lung and aorta of control and STZ-treated rats were compared by using Griess reagent and Western analysis, respectively. Results indicated that STZ-treated rats increased the maximal contractile response of the aorta to phenylephrine (PE), and high $K^+,$ while the sensitivity remained unaltered. Endothelium-dependent relaxation, but not SNP-mediated relaxation, was reduced in STZ-treated rats. Plasma nitrite/nitrates are significantly increased in STZ-treated rats compared to controls. The malondialdehyde (MDA) contents of liver, serum, and aorta of diabetic rats were also significantly increased. Furthermore, nitrotyrosine, a specific foot print of peroxynitrite, was significantly increased in endothelial cells and smooth muscle layers in STZ-induced diabetic aorta. Taken together, the present findings indicate that enhanced release of NO by iNOS along with increased lipid peroxidation in diabetic conditions may be responsible, at least in part, for the augmented contractility, possibly through the modification of endothelial integrity or ecNOS activity of endothelium in STZ-diabetic rat aorta.

• Journal of Ginseng Research
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• v.43 no.1
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• pp.10-19
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• 2019

Background: Frequent overdose of paracetamol (APAP) has become the major cause of acute liver injury. The present study was designed to evaluate the potential protective effects of ginsenoside Rk1 on APAP-induced hepatotoxicity and investigate the underlying mechanisms for the first time. Methods: Mice were treated with Rk1 (10 mg/kg or 20 mg/kg) by oral gavage once per d for 7 d. On the 7th d, allmice treated with 250mg/kg APAP exhibited severeliverinjury after 24 h, and hepatotoxicitywas assessed. Results: Our results showed that pretreatment with Rk1 significantly decreased the levels of serum alanine aminotransferase, aspartate aminotransferase, tumor necrosis factor, and interleukin-$1{\beta}$ compared with the APAP group. Meanwhile, hepatic antioxidants, including superoxide dismutase and glutathione, were elevated compared with the APAP group. In contrast, a significant decrease in levels of the lipid peroxidation product malondialdehyde was observed in the ginsenoside Rk1-treated group compared with the APAP group. These effects were associated with a significant increase of cytochrome P450 E1 and 4-hydroxynonenal levels in liver tissues. Moreover, ginsenoside Rk1 supplementation suppressed activation of apoptotic pathways by increasing Bcl-2 and decreasing Bax protein expression levels, which was shown using western blotting analysis. Histopathological observation also revealed that ginsenoside Rk1 pretreatment significantly reversed APAP-induced necrosis and inflammatory infiltration in liver tissues. Biological indicators of nitrative stress, such as 3-nitrotyrosine, were also inhibited after pretreatment with Rk1 compared with the APAP group. Conclusion: The results clearly suggest that the underlying molecular mechanisms in the hepatoprotection of ginsenoside Rk1 in APAP-induced hepatotoxicity may be due to its antioxidation, antiapoptosis, anti-inflammation, and antinitrative effects.

• Herbal Formula Science
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• v.28 no.1
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• pp.1-13
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• 2020

Objectives : Present study investigated hepatoprotective effects of four types of Taraxaci Herba water extract (TL-F, Taraxaci Herba leaf originated from foreign country; TR-F, Taraxaci Herba root originated from foreign country; TL-K, Taraxaci Herba leaf originated from Korea; TR-K, Taraxaci Herba root originated from Korea) on carbon tetrachloride (CCl₄)-induced acute liver injury. Methods : Mice were administered orally with 200 mg/kg of TL-F, TR-F, TL-K, or TR-K for seven days, and intraperitoneally injected with 0.5 mL/kg of CCl₄ 1 h after last Taraxaci Herba treatment. Silymarin (100 mg/kg) was used as a positive drug. Body weight gain, relative liver weight, serum biochemistry, histopathological and immunohistochemical analyses, and hepatic antioxidant capacity were determined to investigate the hepatoprotective effect of four extracts. Results : Administration of four types of Taraxaci Herba extract increased body weight gain, and decreased relative liver weight in CCl₄-injected mice. As compared to CCl₄ group, TL-F and TR-F significantly decreased serum aspartate aminotransferase activity, while four extracts reduced CCl₄-induced alanine aminotransferase activity. In addition, TL-F and TR-F significantly decreased the numbers of degenerated hepatocytes, infiltrated inflammatory cells, cleaved caspase-3 positive cells, and cleaved PARP positive cells in hepatic tissues. Moreover, TL-F, TR-F, and TR-K administration reduced the lipid peroxidation and nitrotyrosine, and increased glutathione, superoxide dismutase, and catalase activities in hepatic tissues. There were no statistical differences between TL-F- and silymarin-treated group. Conclusion : Of four extracts tested, present results suggest that TL-F is the most favorable candidate against CCl₄-induced acute liver injury through enhancing antioxidant activity.