Protective Effects Of Amino Acids Research Articles

Retracted: Protective Effect of Amino Acids on the Muscle Injury of Aerobics Athletes after Endurance Exercise Based on CT Images.

[This retracts the article DOI: 10.1155/2022/5961267.].

Protective effect of amino acids on the stability of bayberry anthocyanins and the interaction mechanism between l-methionine and cyanidin-3-O-glycoside

The protective effects of three amino acids (l-phenylalanine, l-tryptophan and l-methionine) on the stability of bayberry anthocyanins were investigated. The anthocyanin stability under constant illumination (5000 Lux, 50 Hz) or in the presence of ascorbic acid were evaluated by degradation kinetic parameters, and the interaction between l-methionine and cyanidin-3-O-glucoside (C3G) in a model beverage system was analyzed using Fourier transform infrared spectroscopy, 1H nuclear magnetic resonance, X-ray diffraction, molecular docking, and molecular dynamics simulation. Results indicated that the three amino acids significantly reduced the degradation rate of bayberry anthocyanins (p < 0.05), with the most effect by l-methionine. l-methionine could bind to C3G via hydrogen bonds and Van der Waals forces. This study suggested that l-methionine could well protect anthocyanin against degradation in the aqueous solution and have the potential to be used as a co-pigment to improve the sensory property and extend the shelf life of anthocyanin rich berry products.

Protective Effect of Amino Acids on the Muscle Injury of Aerobics Athletes after Endurance Exercise Based on CT Images.

During the training process, the aerobics athletes gradually increase their technical movements, the appreciation of the movements has been gradually improved, and the injuries of the athletes themselves have also gradually become serious. Based on CT image analysis, we study the protective effect of amino acids on aerobics athletes' muscle injury after endurance exercise. There are three major substance metabolism disorders in patients with muscle sclerosis, which are mainly manifested as decreased glucose tolerance and insulin resistance. Some patients develop muscle-derived diabetes. At the same time, the synthesis of lipids such as cholesterol and apolipoproteins decreases, the production of ketone bodies increases and the body uses more ketones for energy. The BCAA/AAA factor refers to the branched-chain amino acid/aromatic amino acid (BCAA/AAA) value. In amino acid metabolism, plasma albumin decreased significantly, the ratio of amino acids was unbalanced, and BCAA/AAA decreased, which was more likely to induce muscular encephalopathy. Using computer tomography (CT) to study the protective effect of amino acids on muscle injury, 32 aerobics athletes were randomly divided into an intervention group (Ig) and a control group (CG), each with 16 people. After 64-slice spiral CT scanning of muscles and three-dimensional reconstruction, the intervention group and the control group participated in aerobic endurance training 3 weeks in advance to establish a muscle microinjury model. The intervention group took the preprepared BCAA, while the control group did not take it. After three weeks of training, there will be one hour and three hours of aerobics competition. We need to detect changes in blood glucose (BS), creatine kinase (SCK), lactate dehydrogenase (LD), alanine (ALA), and alanine aminotransferase (AA) before and after exercise and 1 hour after exercise and record AVS athletes' pain analysis table. We successfully established the muscle injury model, letting all athletes' VAS score in 6–8 points; after 1 hour of exercise, the measurement results were the same as those of 2 hours. Therefore, after endurance training, the blood glucose content of the intervention group gradually decreased and returned to the original level after 2 hours of exercise, while the control group was lower than the level of exercise after 2 hours of exercise; the content of alanine in the two groups decreased more after 2 hours of exercise; the results of serum creatine kinase in the intervention group were higher than those in the control group after exercise. In the intervention group, lactate dehydrogenase increased rapidly at 2 hours after exercise; the alanine aminotransferase in the intervention group increased after exercise, but there was no significant change in the control group. It is also concluded that the longer the exercise time and the more energy consumption, the more effective the branched-chain amino acids supplement will be. The obtained imaging data can provide a more intuitive and accurate basis for the scientific selection of athletes, and amino acids can promote the synthesis of hormones, accelerate the synthesis of proteins and other products, reduce the content of creatine kinase in the blood, and protect the rapid recovery of muscle damage.

Protective Effects of Amino Acids on Plasmid DNA Damage Induced by Therapeutic Carbon Ions.

Radioprotectors with few side effects are useful for carbon-ion therapy, which directly induces clustering damage in DNA. With the aim of finding the most effective radioprotector, we investigated the effects of selected amino acids which might have chemical DNA-repair functions against therapeutic carbon ions. In the current study, we employed five amino acids: tryptophan (Trp), cysteine (Cys), methionine (Met), valine (Val) and alanine (Ala). Samples of supercoiled pBR322 plasmid DNA with a 17 mM amino acid were prepared in TE buffer (10 mM Tris, 1 mM ethylenediaminetetraacetic acid, pH 7.5). Phosphate buffered saline (PBS) was also used in assays of the 0.17 mM amino acid. The samples were irradiated with carbon-ion beams (290 MeV/u) on 6 cm spread-out Bragg peak at the National Institute of Radiological Sciences and Heavy Ion Medical Accelerator in Chiba, Japan. Breaks in the DNA were detected as changes in the plasmids and quantified by subsequent electrophoresis on agarose gels. DNA damage yields and protection factors for each amino acid were calculated as ratios relative to reagent-free controls. Trp and Cys showed radioprotective effects against plasmid DNA damage induced by carbon-ion beam, both in PBS and TE buffer, comparable to those of Met. The double-strand break (DSB) yields and protective effects of Trp were comparable to those of Cys. The yields of both single-strand breaks and DSBs correlated with the scavenging capacity of hydroxyl radicals (rate constant for scavenging hydroxyl radicals multiplied by the amino acid concentration) in bulk solution. These data indicate that the radioprotective effects of amino acids against plasmid DNA damage induced by carbon ions could be explained primarily by the scavenging capacity of hydroxyl radicals. These findings suggest that some amino acids, such as Trp, Cys and Met, have good potential as radioprotectors for preventing DNA damage in normal tissues in carbon-ion therapy.

The protective effect of amino acids on the copper(II)-catalyzed autoxidation of ascorbic acid

Protection of ascorbic acid (AA:vitamin C) from Cu(Ⅱ)-catalyzed autoxidation is an important aspect of antioxidant chemistry. The autoxidation of AA in the absence and presence of Cu(Ⅱ) ions was investigated in aerated solution at room temperature and I=0.1 ionic strength (KNO3). Effects of eight biochemically important amino acids (alanine, glycine, aspartic acid, asparagine, glutamic acid, glutamine, phenylalanine, and histidine) on this system were studied. The concentration of unoxidized AA remaining in solution was measured with the CUPRAC (cupric ion reducing antioxidant capacity) spectrophotometric method without interference from the amino acids tested. The autoxidation rate constants of AA decreased with increasing amino acid concentration for fixed Cu, and increased with Cu(Ⅱ) for fixed amino acid concentrations. Catalytic autoxidation of AA was inhibited by stable Cuamino acid complexes; histidine, having the highest conditional stability constant for its Cu-complex, showed the strongest inhibitive effect. Since amino acids are food and drug compatible compounds, they can be used in commercial products to increase the stability of vitamin C.

Protective role of l-glutamic acid and l-cysteine in mitigation the chlorpyrifos-induced oxidative stress in rats

Exposure to the organophosphorus insecticide chlorpyrifos (CPF) can lead to oxidative stress. The aim of this work was to investigate and compare the protective effects of amino acids (l-glutamic acid (l-Glu) and l-cysteine (L-Cys) alone or in combination) for the purpose of suppression and mitigation of CPF-induced oxidative stress in rats. Rats were divided into five groups: CPF, CPF/L-Glu, CPF/L-Glu and l-Cys, CPF/L-Cys, control. The level of GSH and the activities of glutathione-related enzymes were determined. The content of lipid peroxidation products was also monitored. The obtained results suggest that level of GSH and activity of GSH-related enzymes was significantly inhibited by CPF. l-Glu and l-Cys were able to prevent CPF-induced oxidative stress. In rats treated with amino acids, we observed less significant or no changes in studied parameters. It was established that the above-mentioned amino acids, administered alone and in their combination, can mitigate and suppress CPF-induced oxidative stress. The most significant mitigation effect was found in rats treated with l-Glu only.

Elental® amino acid component has protective effects on primary cultured hepatocytes and a rat model of acute liver injury

Amino acids can exert protective effects on the liver either when administered as a medication or following an operation. In this study, we examined the protective effects of amino acids on the liver using in vitro and in vivo models by studying their influence on the induction of inducible nitric oxide synthase (iNOS) and nitric oxide production as a liver injury marker in cultured hepatocytes and liver-protective effects in d-galactosamine and lipopolysaccharide (GalN/LPS)-treated rats, respectively. Primary cultured rat hepatocytes were treated with interleukin (IL)-1β in the presence or absence of Elental® amino acid component (EleAA; 17 amino acids). Rats were pretreated with either EleAA or a diet containing selected amino acids followed by GalN/LPS injection. Survival rate and mRNA expression were analyzed. EleAA inhibited iNOS induction through reduction of mRNA synthesis and stability in cultured hepatocytes, indicating prevention of liver injury, but did not show a liver-protective effect in GalN/LPS rats. Among EleAA, Lys, Trp, His, and Arg (4AA) markedly decreased nitric oxide production and inhibited nuclear factor-κB (NF-κB) activation. In GalN/LPS rats, 4AA (3% of each amino acid in diet) increased survival rate by 50% and decreased mRNA expression of iNOS, tumor necrosis factor-α, and cytokine-induced neutrophil chemoattractant-1 in the liver. 4AA reduced NF-κB activation induced by GalN/LPS. 4AA inhibited the expression of inflammatory mediators, in part through inhibition of NF-κB activation in cultured hepatocytes and GalN/LPS-treated rats. The results suggest that EleAA has therapeutic potential for organ injuries including liver.

Influence of amino acids, buffers, and ph on the γ-irradiation-induced degradation of alginates.

Alginate-based biomaterials and medical devices are commonly subjected to γ-irradiation as a means of sterilization, either in the dry state or the gel (hydrated) state. In this process the alginate chains degrade randomly in a dose-dependent manner, altering alginates' material properties. The addition of free radical scavenging amino acids such as histidine and phenylalanine protects the alginate significantly against degradation, as shown by monitoring changes in the molecular weight distributions using SEC-MALLS and determining the pseudo first order rate constants of degradation. Tris buffer (0.5 M), but not acetate, citrate, or phosphate buffers had a similar effect on the degradation rate. Changes in pH itself had only marginal effects on the rate of alginate degradation and on the protective effect of amino acids. Contrary to previous reports, the chemical composition (M/G profile) of the alginates, including homopolymeric mannuronan, was unaltered following irradiation up to 10 kGy.

Effects of amino acids and albumin on erythropoietin carbamoylation

Anemia in chronic renal failure results from inadequate production of erythropoietin and decrease in its biological activity, and the reduced activity of erythropoietin is caused by the presence of plasma inhibitors of erythropoietin. It is reported that one of the inhibitors of erythropoietin is cyanate, a potential uremic toxin formed spontaneously from increased urea due to decreased renal function, and erythropoietin loses its biological activity due to negatively charged cyanate. The purpose of this study is to investigate the protective effects of amino acids, positively charged amino groups, and albumin binding of several toxins on erythropoietin carbamoylation. The degree of change in erythropoietin structure by cyanate was measured by the trinitrobenzenesulphonate reaction and Western blotting. The loss of biological activity of erythropoietin caused by cyanate was measured by injecting erythropoietin into rats with chronic renal failure. The free amino groups in erythropoietin decreased under cyanate treatment in a time- and concentration-dependent manner. In the cyanate treatment group, of the twenty amino acids, phenylalanine, valine, tryptophan, threonine, and lysine prevented the structural modification of erythropoietin, according to Western blot analysis. In addition, of the three proteins, albumin prevented the structural modification of erythropoietin. As for the cyanate with erythropoietin treatment group, only lysine and albumin prevented the loss of biological activity of erythropoietin in the rats. The results of this study suggest that lysine and albumin may play a protective role against renal anemia by erythropoietin carbamoylation in chronic renal failure.

Role of the mTOR complex 1 pathway in the in vivo maintenance of the intestinal mucosa by oral intake of amino acids

Oral intake of nutrients is often compromised in elderly, multimorbid patients, but parenteral nutrition causes intestinal atrophy and impairs intestinal function. To uncover the molecular mechanisms by which amino acids are involved in intestinal atrophy and recovery, we studied whether the rapamycin-sensitive mechanistic target of rapamycin (mTOR) complex 1 (mTORC1) pathway is involved in this process. C57BL/6N mice were fed a glucose solution alone, glucose solution with amino acids or normal chow diet for various lengths of time. Intestinal sections were prepared from these mice and the villus height and villus density were quantified. As a readout for the mTORC1 pathway, the phosphorylation of the ribosomal S6 protein (S6) was analyzed by immunostaining and immunoblotting. To confirm the role of the mTORC1 pathway, the inhibitory effect of a specific mTOR inhibitor, rapamycin, was examined. Inducing fasting in mice fed only glucose caused time-dependent intestinal mucosal atrophy, whereas supplementation with amino acids protected the intestinal mucosa from atrophy. Phosphorylation of S6 decreased in the intestinal mucosa of mice fed only glucose, whereas supplementation with amino acids increased S6 phosphorylation. Importantly, intraperitoneal injection of rapamycin attenuated the protective effect of amino acids on the intestinal mucosa in a pattern consistent with the decrease of S6 phosphorylation. These results indicate that the mTORC1 pathway plays a crucial role in the in vivo maintenance of the intestinal mucosa by the oral intake of amino acids.

Protective effect of amino acids and oligopeptides in combination with a cytostatic agent on lymphoid tissue culture

Protective effect of amino acids and oligopeptides in combination with a cytostatic agent on lymphoid tissue culture

Protective Effects of Amino Acids Against Gabexate Mesilate–Induced Cell Injury in Porcine Aorta Endothelial Cells

Gabexate mesilate (GM), a serine protease inhibitor, often causes severe vascular injury. We previously reported that GM induced necrotic cell death via injury of the cell membrane in porcine aorta endothelial cells (PAECs). In the present study, we investigated the protective effects of amino acids against this GM-induced cell injury in PAECs. L-Cysteine (Cys), glycine (Gly), L-serine, L-glutamine (Gln), L-glutamate (Glu), L-proline, L-methionine, L-threonine, and L-isoleucine significantly inhibited the GM-induced decrease of cell viability. Gly showed the most potent effect among these amino acids. Gly, L-Cys, L-Glu, and L-Gln also inhibited the GM-induced increase in the number of necrotic cells stained by propidium iodide (PI). However, these amino acids had no effect on the GM-induced inhibition of trypsin activity. Strychnine, MK-801, or dichlorokynurenic acid did not affect the protective effect of Gly. Gly completely suppressed the GM-induced increase in PI uptake, which occurred immediately after exposure to GM. These findings suggest that Gly exerts protection against GM-induced cellular membrane injury, and several amino acids such as Gly may be useful for prophylaxis of the GM-induced severe vascular injury.

Antioxidative Activity of Amino Acids on Tissue Oxidative Stress in Human Intestinal Epithelial Cell Model

The protective effects of amino acids against H 2O 2-induced oxidative stress were investigated in an in vitro assay using human intestinal epithelial cells. Caco-2 cells were pretreated with amino acids (1, 2, and 5 mM) for 2 h and then stimulated with 1 mM H 2O 2 for 6 h. The secretion of IL-8, a proinflammatory mediator, was determined by ELISA as an indicator of tissue oxidative stress. The inhibition of H 2O 2-induced IL-8 secretion from Caco-2 cells was observed by pretreatment with Cys, Val, Ile, Leu, Trp, His, Lys, and Ala. Cys enhanced glutathione (GSH) biosynthesis enzyme activity and increased cellular GSH levels. Branched-chain amino acids such as Val, Ile, and Leu elevated activities of GSH S-transferase (GST) and catalase. Trp, His, and Lys caused increases in GST activity. Ala enhanced GSH reductase activity. These data suggest that specific amino acids exert protective effects against tissue oxidative stress in intestinal epithelial cells based on the structure.

Effects of protective agents on membrane fluidity of freeze-dried Lactobacillus delbrueckii ssp. bulgaricus

To evaluate the effect of protective agents upon survival of Lactobacillus delbrueckii ssp. bulgaricus during freeze-drying and storage, and selective amino acids on cell membrane fluidity. The protective effect of amino-acids and sugars at different concentrations was studied by determining the viability of lyophilized cells after storage under air at 30 degrees C. Survival following freeze-drying was improved by all compounds. During storage, neither proline nor maltose had protective effects on lyophilized Lact. delbrueckii ssp. bulgaricus. Glutamate 5% and aspartate 5% showed similar protection capability during freeze-drying (94-95%) and after storage (92-99%). Fluorescence probes (DPH and TMA-DPH) were used to study the effect of both amino acids on membrane fluidity. Polarization decreased with increasing concentrations of glutamate or aspartate. Lowest values were observed with TMA-DPH. Glutamate 5% and aspartate 5% allowed maintaining high viability rates during freeze-drying and storage of Lact. delbrueckii ssp. bulgaricus because of an increase of the membrane fluidity by inserting in the interfacial region of bacterial plasma membrane. These results show the first evidence of the mechanisms underlying glutamate and aspartate as lyoprotectors.

Spectroscopic evaluation of the stabilization of humanized monoclonal antibodies in amino acid formulations

The protective effects of amino acids on stabilizing protein secondary structure were evaluated using diffuse reflectance FTIR spectroscopy, and interactions between proteins and arginine were detected using solid-state NMR spectroscopy. Upon freeze-drying, excipient-free anti-CD11a and anti-IgE antibodies underwent significant changes in their secondary structures. For both antibodies, the amount of intermolecular β-sheet substantially increased and the native conformation of intramolecular β-sheet content decreased considerably. The addition of amino acids to the formulations reduced protein secondary structure alterations in a concentration-dependent manner. Histidine and arginine appeared to be the most protective excipients (of the amino acids studied) in inhibiting protein secondary structural changes. Solid-state NMR illustrated that non-covalent interactions (e.g., hydrogen bonding, ion–dipole interactions) were formed between the arginine side chain and the protein. Glycine is the least effective additive of those studied in preventing secondary structure changes upon freeze-drying.Despite secondary structural changes, freeze-dried protein in the presence and absence of amino acids refolded back into its native conformation upon reconstitution in water.

DNA–Protein Crosslinks Induced by Nickel Compounds in Isolated Rat Lymphocytes: Role of Reactive Oxygen Species and Specific Amino Acids

Isolated rat lymphocytes in salts-glucose medium (pH 7.2) were incubated with nickel chloride, nickel acetate, nickel sulfate, and a soluble form of nickel subsulfide (0–2 mM) at 37°C for 2 h. The soluble form of nickel subsulfide induced a significant increase in DNA–protein crosslinks (DPXLs) (111%) beginning at 0.5 mM and a maximum increase of 700% from that of the control value was reached at a 2 mM concentration, whereas nickel sulfate produced only a 65% increase of such crosslinks at the 2 mM concentration only. No significant reduction in viability of rat lymphocytes (as measured by trypan blue exclusion) due to these nickel compounds was observed at any concentration used. Time-course studies of DPXLs and cellular viability due to 2 mM nickel subsulfide indicate that DPXL formation may not be due in part to cellular necrosis. Coincubation of nickel subsulfide (2 mM) with l-histidine (16 mM), l-cysteine (4 or 8 mM), or l-aspartic acid (24 mM) significantly reduced the DPXLs induced by 2 mM nickel subsulfide. But Mg2+ even at 24 mM failed to antagonize nickel subsulfide-induced increase in DPXLs. High concentrations of these amino acids significantly decreased the accumulation of Ni2+ from nickel subsulfide in lymphocytes, suggesting that such reduction of cellular uptake of Ni2+ by these amino acids is partly responsible for the potent protective effects of these amino acids against such genotoxicity of nickel subsulfide. In vitro exposure of lymphocytes to nickel subsulfide (0–2 mM) increased the formation of reactive oxygen species (ROS) in a concentration-dependent manner. Furthermore, coincubation of 2 mM nickel subsulfide with catalase, dimethylthiourea, mannitol, or vitamin C at 37°C for 2 h resulted in a significant decrease of nickel subsulfide-induced formation of DPXLs, suggesting that nickel subsulfide-induced DPXLs formation in isolated rat lymphocytes is caused by the formation of ROS. The amino acid treatment also abrogated Ni3S2-induced generation of ROS. Deferoxamine (a highly specific iron chelator) treatment prevented nickel subsulfide-induced DNA–protein crosslink formation, suggesting that Ni2+-induced DPXL formation in rat lymphocytes is caused by the induction of Fenton/Haber–Weiss reaction, generating hydroxyl radicals. The potent protective effects of these specific amino acids against nickel subsulfide-induced DPXL formation in isolated rat lymphocytes may be due in part to impaired cellular uptake of Ni2+, inhibition of the binding of Ni2+ to deproteinized DNA, and a reduction in reactive oxygen species.

Protection of mitochondrial and heart function by amino acids after ischemia and cardioplegia

The effects of amino acids in protecting against ischemic/reperfusion injury were tested in two experimental models: the isolated perfused rat heart subjected to 21 min of zero flow ischemia (37°) followed by 40 min of reperfusion and the isolated perfused rabbit heart subjected to 300 min of cardioplegic arrest (29°) followed by 60 min of reperfusion. In both cases, the addition of amino acids to the perfusion medium significantly improved the recovery of cardiac contractile function. The protective effects of amino acids were associate with a preservation of mitochondrial respiratory activity. These findings suggest that amino acids by replenishing mitochondrial matrix levels of critical TCA cycle substrates, such as malate, stimulate mitochondrial respiration and thereby enhance the recovery of heart function.

Protective effects of amino acids against freeze-thaw damage in mammalian cells

Amino acids were tested for their effectiveness as cryoprotectants. From the results of this study, the mean fractional area loss of amino acid residues upon incorporation in globular proteins, a measure of hydrophobicity, is generally inversely proportional to the freeze-thaw protection by these free amino acids. However, the pattern of protection (“fingerprint”) of cells by various amino acids is different from that of the enzymes liver alcohol dehydrogenase and calcium ATPase of the sarcoplasmic reticulum. Furthermore, unlike the case with these enzymes, for cells glutamine is the best cryoprotective agent of the amino acids tested.

Inhibitory Effect of Amino Acids and Dipeptides on the Sensitized Photooxidation of Fats

AbstractThe protective effect of amino acids and dipeptides on the singlet molecular oxygen photo‐oxidation of soybean oil and thier FAME was investigated, in homogeneous media and in aqueous emulsions. Soybean oil was chosen as an example of fat due to its particular stability problem. In the presence of 10–100 ppm of the amino acids, photo‐oxidation of the fats in relatively concentrated solutions, was considerably retarded when exposed to visible light, with an added sensitizer. The study indicates that amino acids and peptides, could acd as protective agents against fats photo‐oxidation, specially in foods containing oxidizable non saturated fatty acids, constituted in many cases by emulsions, where fats can simultaneously be disolved with proteineaceous compounds.

Protective effects of glutamate and aspartate on the ischemic and reperfused myocardium of hearts from starved rats.

To determine the protective effects of amino acids on the ischemic and reperfused myocardium, an experimental study was carried out. Rats were starved for 20 days, then separated into the following three groups: group I: control, group II: glutamate and aspartate were administered before aortic cross clamping for 5 minutes, and added to the cardioplegic solution, group III: glutamate and aspartate were given during the initial 15 minutes of reperfusion. After 25 minutes of equilibration, the hearts were made ischemic at 35.5 degrees C for 45 minutes, and arrested with high potassium cardioplegic solution immediately after aortic cross clamping. The recovery of cardiac output in group II was significantly (p less than 0.05 vs group I & III) better than that in groups I and III, with no difference between groups I and III. Tissue analysis for high energy phosphate compounds revealed that the levels of ATP and total adenine nucleotides were significantly (p less than 0.05 vs group I & III) higher in group II. Lactate output during the initial three minutes of reperfusion was decreased to the greatest extent in group II. Metabolic studies involving the examination of oxygen utilization also revealed no differences between groups I and III. Thus, addition of glutamate and aspartate before and during aortic cross clamping is effective for reducing ischemic damage, however, the administration of these amino acids during the reperfusion is without significant effects.