Effect of different selenium sources and concentrations on glutathione peroxidase activity and cholesterol metabolism of beef cattle

The objective of this study was to investigate the effects of different Se sources and concentrations on glutathione forms and cholesterol metabolism in beef cattle. Sixty-three Nellore bulls (412 ± 19 kg BW; 24 months old) were randomly assigned to a completely randomized design in a 2×3 + 1 factorial arrangement (63 pens; one animal/pen) with two Se sources (sodium selenite, ING and Se-yeast, ORG), three concentrations (0.3, 0.9 and 2.7 mg supplemental Se/kg DM), and control treatment (without Se supplementation) fed for 90 days. Blood samples were collected on d 0, 28, 56, and 84. Muscle and liver samples were collected at harvest. Hepatic GSSG (P = 0.004), GSH/GSSG ratio (P = 0.030), and GSH-Px (P = 0.004) were affected by Se source x concentration interaction. Oxidized glutathione was higher in the ORG group vs. ING at concentration 2.7 mg supplemental Se/kg DM, but at 0.3 mg supplemental Se/kg DM the ING group was higher than ORG. The liver GSH-Px activity was higher in the ORG group vs. ING at concentration 0.9 and 2.7 mg supplemental Se/kg DM. The GSH/GSSG ratio was the highest in animals fed 0.3 mg supplemental Se/kg DM of ORG. Selenium liver concentration increased linearly with the supplemental Se concentration in the diet (y = 0.0583 + 0.4254x, R 2 = 0.92, P < 0.0001), regardless of source. Total meat cholesterol was greater (P < 0.001) in CON (control) vs. SUP (supplemented, regardless source) group. The muscle GSH-Px activity was higher (P < 0.001) in SUP vs. CON and increased (P < 0.004) with increasing supplemental Se concentrations. There was an increase on VLDL, glucose, and triglycerides in ORG vs. ING (P ≤ 0.035). In general, serum Se was higher (P < 0.001) in SUP vs. CON and increased with increasing supplemental Se concentration. Lastly, the HMGCR concentration was lower (P = 0.002) in SUP (0.39 ng/mL) vs. CON (0.55 ng/mL). Selenium supplementation with different sources and concentrations has the potential to affect cholesterol metabolism by affecting GSH/GSSG ratio, GSH-Px, and the HMGCR.

Therapeutic Artemether-Lumefantrine Modulated Monosodium Glutamate-Related Adversity on Rats’ Kidney Histology and Antioxidant Response Bio-Indicators

Co-intake-related interactive-synergistic influence of artemether-lumefantrine, AL and monosodium glutamate, MSG that separately mediated oxidative stress could be significant on the kidney actively involved in xenobiotic detoxification and elimination. Thus, influence of AL on rats’ kidney histomorphology and antioxidant bio-indicators following MSG-challenge was assessed. For 7 days, thirty rats (n = 5) were respectively exposed to vehicle (distilled water), therapeutic AL (TAL), high AL (HAL), MSG, MSG plus TAL or MSG plus HAL. Significant (P<0.05) results comparison showed highest and least (P<0.05) albumin concentration (Mg/dl) in TAL-fed (3.76±0.33) and MSG-fed (1.88±0.70), rats. Total protein concentration (Mg/dl) in MSG-fed (4.04±2.04) and HAL-fed (4.76±1.92), rats lowered markedly. Highest glutathione peroxidase activity (IU/L) in TAL-fed (30.74±12.46) lowered in MSG plus HAL-fed (20.11±6.08) and MSG-fed (20.33±4.85), rats. Catalase activity (IU/L) in control was highest (4.89 ± 0.26) but least (2.58 ± 1.06) in MSG-fed rats. Zinc and Magnesium concentration (Mg/dl) was respectively highest (58.99±5.10) and least (3.48±0.31) in MSG plus HAL-fed but least (18.80±7.77) and highest (4.38±1.67) in MSG-fed, rats. Malondialdehyde concentration (µmol/ml) in MSG plus HAL-fed rats (4.04±0.67) was highest (P<0.05) and least (P<0.05) in HAL-fed rats (1.18±0.11). Differences in superoxide dismutase activity (IU/L) were, however, non-significant (P>0.05).Rats’ kidney photomicrographs (H&E × 400) revealed normal histo-architecture in control but varied degree of fibroplasias (TAL- ,HAL- and MSG plus TAL-fed) and necrosis with infiltrations (MSG plus HAL-and MSG-fed), rats. These demonstrated MSG-related adversity and significant modulation response of TAL, unlike HAL, on the rats’ kidney histology and studied antioxidant response bio-indicators.

Experience of measuring glutathione peroxidase activity in surgically induced endometrial-like lesions in rats

BACKGROUND: Endometriosis is known to be linked with altered activities of antioxidant enzymes and with their gene polymorphisms. Progestins are known to induce glutathione peroxidase activity in the endometrium and promote reduction of endometrial lesions. It could be useful to estimate the correlation between the activity of glutathione peroxidase within endometrial lesions and their degree of reduction. AIM: The present study was aimed at estimating glutathione peroxidase activity in surgically induced endometrial-like lesions of different degree of reduction in rat model of endometriosis. MATERIALS AND METHODS: The method for determining glutathione peroxidase activity using hydrogen peroxide as a substrate and 5,5-dithiobis(2-nitrobenzoic acid) for estimation of residual reduced glutathione was applied for quantitative analysis of the enzyme activity in endometriotic foci, surgically induced in female Wistar rats. An assay of glutathione peroxidase activity in tissue homogenates was performed at 37C in a reaction medium containing Tris-HCl buffer supplemented with tetrasodium ethylenediaminetetraacetate and sodium azide (pH 8.5) in the presence of 0.55 mM reduced glutathione and 0.192 mM hydrogen peroxide. Before adding trichloroacetic acid, 40-second incubation was used. The correlation between the specific activity of the enzyme and protein amount in endometriotic foci was estimated. RESULTS: In a rat model of endometriosis, there was a high, well-determined glutathione peroxidase activity in endometriotic foci. For the same endometriotic tissue sample, the enzymatic activity was proportional to the amount of protein in the reaction mixture. The range of specific glutathione peroxidase activity was 2.436.45 micromoles of consumed glutathione per minute per milligram of protein (n = 7). In most reduced endometriotic foci (with the minimum amount of endometriotic tissue), the highest specific activity of glutathione peroxidase was found (the Spearmans rho of 0.93 with p = 0.0067). CONCLUSIONS: The method for determining glutathione peroxidase activity using hydrogen peroxide and 5,5-dithiobis(2-nitrobenzoic acid) is convenient for working with the endometriotic tissue in a rat model of endometriosis. We can accept, with p 0.01, that weight of endometriotic foci is negatively linked with specific glutathione peroxidase activity within their tissue. The results are analogous to the previously obtained data on catalase activity and suggest the involvement of both antioxidant enzymes in reduction of endometrial lesions.

A validated method to assess glutathione peroxidase enzyme activity

This essay presents a reliable, effective and easy procedure for measuring glutathione peroxidase activity (Gpx). The enzyme samples were incubated with phosphate buffer, which included appropriate concentrations of glutathione and peroxide as substrates, to determine the Gpx activity. After a sufficient incubation time, the CUPRAC reagent (Cu(Nc) 2 2+ ) was added to stop the enzyme’s reaction. The unreacted substrates act to reduce Cu(II)-neocuproine complex (Cu(Nc) 2 2+ ) to strongly coloured Cu(I)-neocuproine complex (Cu(Nc) 2 + ) that was measured spectrophotometrically at 450 nm (CUPRAC method). The glutathione peroxidase activity was linked to a decrease in the absorbance of the coloured Cu(I)-neocuproine complex (Cu(Nc) 2 + ). The procedure uses the Box–Behnken design (BBD) to optimise the formation of the Cu(I)-neocuproine complex (Cu(Nc) 2 + ). The response surface methodology (RSM) is used to determine the accuracy of the method. This new protocol was confirmed by applying a Bland–Altman plot analysis of Gpx activity in matched samples using the Gpx-DTNB assay. The correlation coefficient between the two protocols was 0.9967. This means that the new protocol was very accurate and on par with the comparison method.

Glutathione Content and Glutathione Peroxidase Activity of Sperm in Males with Unexplained Infertility

Summary The study aimed to investigate glutathione peroxidase (GPx) activity and glutathione (GSH) levels in the sperm of patients with unexplained infertility. The sperm samples were collected from subjects with normal semen parameters divided into fertile and infertile groups. Sperm analysis was performed according to the 2010 WHO criteria. Measurement of the GPx activity and GSH were performed by enzymatic assay kits. The higher enzymatic activity recorded in spermatozoa and seminal plasma in the infertile group was close to the significant one – p=0.054 for seminal plasma andp= 0.086 for the spermatozoa.GSH levels were higher in the fertile group in the seminal plasma (p=0.045). Defining the causes of unexplained infertility requires the addition of oxidative stress. In patients with unexplained infertility, the level of glutathione is reduced, and the activity of one of the significant enzyme antioxidants GPx is not changed significantly and even shows a tendency to rise.

A Plant-Based Meal Reduces Postprandial Oxidative and Dicarbonyl Stress in Men with Diabetes or Obesity more than an Energy- and Macronutrient-Matched Conventional Meal in a Randomized Crossover Study

Background: Increased oxidative/dicarbonyl stress and chronic inflammation are considered key pathological mediators in the progression of complications in type 2 diabetes (T2D) and obesity. Lifestyle and diet composition have a major impact. In this study, we tested the effects of a vegan (V) and a conventional meat containg (M) meal, matched for energy and macronutrients, on postprandial oxidative and dicarbonyl stress, inflammatory markers and appetite hormones. Methods: A randomised crossover design was used to evaluate T2D, obese and control participants (n=20 in each group), with serum concentrations of analytes determined at 0, 120 and 180 minutes. Repeated-measures ANOVA was used for statistical analysis.Results: Postprandial glucose, triglycerides and free fatty acid responses were similar after both meals. After the V-meal consumption, we observed decreased postprandial concentrations of oxidised glutathione (p˂0.001) and increased glutathione peroxidase activity (p=0.045) compared with the M-meal in T2D subjects. In obese participants, V-meal consumption increased postprandial concentrations of reduced glutathione (p=0.041) and decreased methylglyoxal concentrations (p=0.023). There were no differences in postprandial secretion of TNFa, MCP-1 or ghrelin, but we did observe higher postprandial secretion of leptin after the V-meal in T2D subjects (p=0.002) compared with the M-meal. Conclusions: The results show that a plant-based meal is efficient in ameliorating the postprandial oxidative and dicarbonyl stress compared to a conventional energy- and macronutrient-matched meal, indicating the therapeutic potential of plant-based nutrition in improving the progression of complications in T2D and obese patients.Registered under ClinicalTrials.gov Identifier No. NCT02474147.

Study of Malondialdehyde Level and Glutathione Peroxidase Activity in Patients Suffering from Malaria

Introduction: Malaria is one of the most common Parasitic infection prevalent worldwide especially in India, South Asia and Africa. About 250 million cases and approximately One million deaths of malaria reported per year worldwide. Oxidative stress (O.S.) has been implicated as possible mediator of thrombocytopenia in malarial patients. All eukaryotic cells, specially immune effector cells generate reactive oxygen species (ROS) and reactive nitrogen species (RNS) as a mean to combat invading microbes i.e. via the ' Oxidative burst', which increases the oxidative burden on the microbe to lethal levels. An excess of ROS such as superoxide anions, hydrogen peroxide (H2O2), hydroxyl radicals and /or RNS, such as nitric oxide (NO) and peroxynitrite (ONOO-) creates a potentially dangerous situation known as oxidative or nitrosative stress respectively. Aim: Present study aims to study the status of serum Malondialdehyde and Glutathione Peroxidase activity in hemolysate among the patients with Malaria. Materials and Methods: This is cross-sectional observational study on 200 non-treated malaria patients, compared with 100 normal individuals. Out of total 200 malaria patients 96 were plasmodium (P) vivax & 104 were P falciparum diagnosed cases. Results: Mean MDA level in the P. Vivax malaria cases was 12.29 + 0.32 micromole/L which was found to be higher compared to the controls with mean MDA level is 6.55+ 0.24 micromole/L, whereas the mean MDA level in P. Falciparum malaria cases was 13.5+ 0.18 micromole/L which was higher compared to the controls with mean MDA level of 6.55+ 0.24 micromole/L. Conclusion: The present study on malaria explains the role of oxidative stress in the pathophysiology of malaria which is a multifactorial phenomenon and represents an important aspect of the intricate and complex host- parasite relationship. Oxidative stress is aggravated by reduced effectiveness of the antioxidant defence system; hence it is advised to provide antioxidant supplements through diet that can reduce the disease severity and risk of death during infection.