Influence of estrogen on glutathione levels and glutathione-metabolizing enzymes in uteri and R3230AC mammary tumors of rats

The glutathione content and the activities of several enzymes in its metabolism, glutathione reductase, glutathione peroxidase and γ-glutamyl transpeptidase, were assayed in uteri obtained from estrogen-treated rats and in R3230AC mammary adenocarcinomas obtained from ovariectomized, intact and estrogen-treated hosts. Normal mammary glands, obtained 10–12 days post-partum, were also examined for these parameters.A daily pharmacological dose of 0.4 μg of estradiol-17β induced a maximal increase in uterine weight and in reduced glutathione (GSH); higher doses of estrogen did not significantly increase either of these parameters. Levels of oxidized glutathione (GSSG) were comparable in both estrogen-treated and untreated rats. The time course of the estrogen-induced uterotrophic response was associated with increases in glutathione reductase, glutathione peroxidase and γ-glutamyl transpeptidase activities with the increased GSH level preceding the increase in uterine weight. Compared to neoplasms from intact or ovariectomized animals, tumors from estrogen-treated hosts exhibited significant decreases in levels of GSSG and GSH, as well as in glutathione reductase and glutathione peroxidase activities, but demonstrated a significant elevation of γ-glutamyl transpeptidase activity. Normal glands from lactating rats had decreased GSH levels, lower activities of glutathione reductase and glutathione peroxidase, but elevated γ-glutamyl transpeptidase activity versus tumors from intact rats. Tumors from estrogen-treated rats more closely resembled mammary glands during lactation. The divergent growth responses elicited by estrogen in the uterus and mammary tumor are correlated with the observed changes in GSH levels and enzymes involved in glutathione metabolism.     

高血糖加重脑缺血损伤机制的研究现状

脑缺血是引起人类死亡的一个重要原因,由于其发病的分子机制十分复杂,各种因子作用相互影响,且多数因子的作用同时存在损伤和保护两种机制,使得脑缺血的研究充满了困难。目前众多研究都证实高血糖对缺血脑组织有损害作用,并可能导致局部或广泛缺血后预后更差。本文依据近几年的实验,重点阐述了五种最新的高血糖加重脑缺血过程和预后损伤的机制假说,包括高血糖通过引起过量谷氨酸释放导致的Ca2^＋大量内流造成损伤、高血糖状态下造成氧化应激从而产生各种自由基对神经元造成损伤、炎症因子相关的损伤、高血糖相关的血液灌流的减少以及高血糖造成脑内酸中毒从而引起损伤。期望这些对机制的探讨能够上加深广大医药研究人员对高血糖加重脑缺血损伤的认识,帮助找到新的药物作用靶点和治疗手段,启发新的研究思路。     

Effect of ischemia and reperfusion on antioxidant enzymes and mitochondrial inner membrane proteins in perfused rat heart

Experiments were performed to investigate the effects of 60 min severe global ischemia followed by 30 min reperfusion on the antioxidant enzymatic system in the isolated perfused rat heart. Ischemia induced a significant increase of cytoplasmic and mitochondrial selenium-dependent glutathione peroxidase (EC 1.11.1.9) activity. In reperfused hearts, only the mitochondrial form showed a further significant increase. Glutathione reductase (EC 1.6.4.2) was increased in ischemic hearts, whilst the reperfused hearts showed a decrease towards the level found in aerobic hearts. Mitochondrial superoxide dismutase (EC 1.15.1.1) activity was depressed in ischemic as well as in reperfused hearts, though the cytoplasmic form was unmodified. Catalase (EC 1.11.1.6), glucose-6-phosphate dehydrogenase (EC 1.1.1.49) and glutathione transferase (EC 2.5.1.18) activities were unchanged throughout the experiment. Ischemia and reperfusion induced a significant fall in tissue-reduced glutathione content concomitant with an increase of its oxidized form. We have also studied the mitochondrial inner membrane proteins for both molecular weight, with Coomassie blue, and thiol status, with monobromobimane stain, using a sodium dodecyl sulfate polyacrylamide gel electrophoresis technique. Neither ischemia nor reperfusion effected any relevant modification of the molecular weight of the mitochondrial inner-membrane proteins either in the presence or absence of a reducing agent. However, two of these proteins with an apparent molecular weight of 52 0000 and 12 000 showed a decrease in the monobromobimane stain, probably due to the oxidation of their thiol groups.     

缺血性脑卒中患者脑内微出血的发生及危险因素

目的:探讨脑内微出血(CMB)在缺血性脑卒中患者中的发生及相关危险因素。方法:连续选取住院的缺血性脑卒中患者250例,分析其磁共振成像(MRI)表现。根据有无CMB将患者分为CMB组(80例)及无CMB组(170例)。详细记录临床资料,观察CMB的个数、陈旧性腔隙性脑梗死的个数和脑白质改变(WMC)的严重程度。结果:单因素分析显示年龄、高血压病、既往脑梗死病史、脑白质改变、陈旧性腔隙性脑梗死及口服抗血小板聚集药物史与CMB的发生有关。Logistic回归分析显示高血压、既往有脑梗死病史及WMC分值为CMB的独立危险因素。结论:CMB与脑微血管病变之间有密切关系,高血压、既往有脑梗死病史及WMC分值为缺血性脑卒中患者发生CMB的独立危险因素。     

Cerebral glucose transporter: The possible therapeutic target for ischemic stroke

Hyperglycemia is considered to be associated with poor outcomes of ischemic stroke. However, it is controversial about the blood glucose-lowering therapy in patients with stroke. According to the current reports, hyperglycemia is an indicator of severe stroke and cannot increase cerebral glucose content but promotes further ischemia in brain. Consequently, cerebral glucose control is significant to maintain the energy homeostasis. Compared with blood glucose level, the cerebral glucose content, controlled by glucose transporters (GLUTs), is more directly and important to maintain the energy supply in brain, especially to the patients with ischemic stroke. Some active materials, such as Glucagon-like peptide-1, progesterone, tPA and N-acetylcysteine, have been found to ameliorate ischemic stroke by regulating GLUTs expression. Therefore, this review discusses the significance of cerebral glucose level and GLUTs. Additionally, cerebral GLUTs and their actions in ischemic stroke are detailed in order to promote research on GLUTs as a possible therapeutic target for ischemic stroke.     

Glutathione system in erythrocytes and plasma in viral hepatites

In all 5 acute viral hepatites (AVHs) and chronic viral hepatites (CVHs) there was the increase of erythrocyte activities of glutathione peroxidase (GPx) and glutathione reductase (GR), and the decrease in reduced glutathione (GSH) concentration. In blood plasma there was accumulation of GPx, glutathione S-transferase (GST), and γ-glutamyl transferase (GGT). GSH and GR increased in plasma only in AVHs. Erythrocyte GST increased in CVH C. Evidently changes in the erythrocyte glutathione system represent reactions to oxidative stress and in blood plasma they are consequences of inflammation and hepatocyte cytolysis. Changes were more pronounced in moderate than in severe disease course. These changes have pathogenic importance and can be used in addition to complex diagnostics. These changes significantly differ from the changes found in chronic gall-bladder diseases. It is important to analyze glutathione system separately in erythrocytes and blood plasma and not in the whole blood.     

Metabolic flux analysis of postburn hepatic hypermetabolism

The hepatic response to severe injury is characterized by a marked upregulation of glucose, fatty acid, and amino acid turnover, which, if persistent, predisposes the patient to progressive organ dysfunction. To study the effect of injury on liver intermediary metabolism, metabolic flux analysis was applied to isolated perfused livers of burned and sham-burned rats. Intracellular fluxes were calculated using metabolite measurements and a stoichiometric balance model. Significant flux increases were found for multiple pathways, including mitochondrial electron transport, the TCA and urea cycles, gluconeogenesis, and pentose phosphate pathway (PPP). The burn-induced increase in gluconeogenesis did not significantly increase glucose output. Instead, glucose-6-phosphate was diverted into the PPP. These changes were paralleled by increases in glucose-6-phosphate dehydrogenase (G6PDH) and glutathione reductase (GR) activities. Given that G6PDH and GR are the most significant NADPH producers and consumers in the liver, respectively, and that GR is responsible for recycling the free radical scavenger glutathione, these data are consistent with the notion that hepatic metabolic changes are in part due to the induction of liver antioxidant defenses.     

老年H型高血压合并急性缺血性脑卒中患者血清omentin-1、Irisin水平与病情及预后的关系研究

目的:探讨老年H型高血压合并急性缺血性脑卒中患者血清网膜素-1(omentin-1)、鸢尾素(Irisin)水平与病情及预后的关系。方法:选择2017年6月-2019年9月我院收治的老年H型高血压合并急性缺血性脑卒中患者92例,记作合并脑卒中组,根据美国国立卫生研究院卒中量表(NIHSS)评分将患者分为轻症组28例(NIHSS评分≤4分)、中症组39例(5分≤NIHSS评分≤20分)和重症组25例(NIHSS评分>20分),根据改良Rankin量表(mRS)评分将患者分为预后不良组28例(mRS评分>2分)和预后良好组64例(mRS评分≤2分)。另选择同期我院收治的单纯老年H型高血压患者90例作为单纯H型高血压组,分析合并脑卒中组患者血清omentin-1、Irisin水平及omentin-1、Irisin与NIHSS评分、mRS评分的相关性,并应用ROC曲线分析血清omentin-1、Irisin水平对患者预后的预测价值。结果:合并脑卒中组血清omentin-1、Irisin水平显著低于单纯H型高血压组(P<0.05),随脑卒中神经缺损严重程度的升高,H型高血压合并急性缺血性脑卒中患者血清omentin-1、Irisin水平逐渐降低(P<0.05),预后不良组血清omentin-1、Irisin水平显著低于预后良好组(P<0.05)。老年H型高血压合并急性缺血性脑卒中患者血清omentin-1、Irisin水平与NIHSS评分及mRS评分均呈负相关(P<0.05)。omentin-1最佳临界值为105.36 ng/ml,敏感度为78.23%,特异度为83.44%;Irisin最佳临界值为90.77 ng/L,敏感度为71.00%,特异度为61.43%。结论:老年H型高血压合并急性缺血性脑卒中患者血清omentin-1、Irisin水平异常降低,其水平与神经缺损程度和预后呈负相关,血清omentin-1、Irisin对老年H型高血压发生急性缺血性脑卒中的预后评估具有一定价值。     

黄土高原冰草叶片抗坏血酸和谷胱甘肽合成及循环代谢对干旱胁迫的生理响应

通过盆栽实验, 对干旱胁迫下黄土高原地区冰草(Agropyron cristatum)叶片的抗坏血酸和谷胱甘肽合成及循环代谢相关酶及物质含量进行了研究。结果表明: 冰草可以通过增强叶片的抗坏血酸和谷胱甘肽合成及循环代谢酶: 抗坏血酸过氧化物酶、谷胱甘肽还原酶、脱氢抗坏血酸还原酶、单脱氢抗坏血酸还原酶、L-半乳糖酸-1, 4-内酯脱氢酶和γ-谷氨酰半胱氨酸合成酶活性, 维持植物体内抗坏血酸和谷胱甘肽水平及氧化还原状态, 从而抵御干旱造成的氧化胁迫。但叶片抗坏血酸和谷胱甘肽合成及循环代谢对不同水平干旱胁迫的响应, 随胁迫时间的延长而不同。在胁迫24天以前, 严重干旱下叶片的抗坏血酸和谷胱甘肽合成及循环代谢增强较显著; 在胁迫24天后, 由于该胁迫下植物所遭受的氧化胁迫较为严重, 叶片中上述6种酶的活性均呈降低趋势。而在中度干旱下叶片抗坏血酸和谷胱甘肽合成及循环代谢相关的6种酶在整个胁迫过程中均保持较高的活性。这说明, 冰草能够长时间有效地抵御中度干旱所造成的氧化胁迫, 但只能在一定时间范围内有效地抵御严重干旱所造成的氧化胁迫, 胁迫时间延长则会降低其抵御严重干旱的能力。     

The effects of selenium depletion and repletion on the metabolism of thyroid hormones in the rat

Rats were fed selenium-deficient (less than 0.005 mg selenium/kg) or selenium-supplemented diets (0.1 mg selenium/kg, as Na2SeO2) for up to five wks from weaning to assess the effects of developing selenium deficiency on the metabolism of thyroid hormones. Within two wks 3:5,3'-triiodothyronine (T3) production from thyroxine (T4) in liver homogenates from selenium-deficient rats was significantly lower compared with the activity in liver homogenates from selenium-supplemented rats. This decreased activity was probably responsible, in part, for the higher T4 and lower T3 concentrations in plasma from the selenium-deficient rats after 3, 4, and 5 weeks of experiment. Repletion of selenium-deficient rats with single intra-peritoneal injections of 200 micrograms selenium/kg body wt. (as Na2SeO3) 5 days before sampling reversed the effects of the deficiency on thyroid hormone metabolism and significantly increased liver and plasma glutathione peroxidase activities. However a dose of 10 micrograms selenium/kg body wt given to rats of similar low selenium status had no effect on thyroid hormone metabolism or glutathione peroxidase activity but did reverse the increase in hepatic glutathione S-transferase activity characteristic of severe selenium deficiency. Imbalances in thyroid hormone metabolism are an early consequence of selenium deficiency and are probably not related to changes in hepatic xenobiotic metabolizing enzymes associated with severe deficiency.     

Phospholipids composition of the myocardium in patients with ischemic heart disease and its connection to arrhythmias

The purpose of this study was to establish phospholipid composition of the myocardium in patients with ischemic heart disease, and to estimate possible correlation of biochemical parameters with myocardium extrasystolic activity. The patients (n = 28) including 15 patients with ischemic heart disease and 13 patients with secondary atrium septum defect (control group) were studied. During surgical intervention the right atrium myocardium bioptates were taken. Phospholipid metabolism was studied in the myocardium samples. At the eve of surgical intervention a holter monitoring was performed. Deep changes in the myocardium lipid metabolism were found, including accumulation of free and estherified cholesterol, lysophospholipids, and sphingomyeline. An increase of free cholesterol content was accompanied by accumulation of sphingomyeline. This can be an evidence of changes in the constitution of lipid rafts. Extrasystoles, particularly ventricular ones, in patients with ischemic heart disease might depend on accumulation of lysophospholipids as they took place simultaneously with it.     

Effect of picroliv on glutathione metabolism in liver and brain of Mastomys natalensis infected with Plasmodium berghei.

Administration of picroliv, the active principle from Picrorhiza kurrooa, at a dose of 6 mg/kg, po for two weeks showed significant protection against changes in liver and brain glutathione metabolism of Plasmodium berghei infected Mastomys natalensis. The depletion of reduced glutathione level and inhibition of glutathione-S-transferase, glutathione reductase and glutathione peroxidase activities due to P. berghei infection were markedly recovered by picroliv. The increased levels of lipid peroxidation products in damaged tissues were also reduced along with the recovery of glutathione metabolism.     

Imbalance in the enzymatic system of production and consumption of active oxygen species in liver of AKR mice with spontaneous leucosis

Activities of protective antioxidant enzymes, the rate of superoxide formation (v) in microsomal membranes and submitochondrial particles (SMP), and the concentrations of reduced and oxidized glutathione in cytosol were studied in the liver of AKR mice during the development of spontaneous leucosis. It was found that in the latent period of leucosis (mice of 3-6 months of age) the glutathione reductase (GR) activity in cytosol and mitochondria decreased and v in SMP increased. The increase in v in SMP did not result in the induction of Mn-SOD. In this stage of leucosis, the activities of Cu,Zn-SOD, GSH-Px, and G-6-PDH in cytosol were unchanged; at the same time, the GR activity and the concentration of reduced glutathione smoothly decreased. In the stage of developed leucosis (mice of 7-9 months of age), non-synchronous changes in the antioxidant system resulting in the shift of metabolism towards the prooxidant state were found. Comparison of our findings and the literature data demonstrates that the observed decrease in the SOD/GSH-Px ratio, the decrease in GR activity, and the increase in the v/Mn-SOD activity ratio are typical for pre-neoplastic changes in cell metabolism.     

Redox imbalance in peripheral blood of type 1 myotonic dystrophy patients

Objectives: The aim of our study was to determine if redox imbalance caused by the activities of antioxidant enzymes existed in erythrocytes of type 1 myotonic dystrophy (DM1) patients.

Methods: The activities of erythrocyte superoxide dismutase, catalase, glutathione peroxidase, and glutathione reductase were measured in 30 DM1 patients and 15 healthy controls (HCs). The obtained values were correlated with the Muscular Impairment Rating Scale (MIRS) score and creatine kinase (CK).

Results: Superoxide dismutase and catalase activities were lower in DM1 patients compared to HCs. A positive correlation was found between disease duration and MIRS score as well as with glutathione reductase activity. In DM1 patients, there were positive correlations between catalase, glutathione peroxidase, and glutathione reductase activities. After sub-dividing DM1 patients according to CK levels, superoxide dismutase activity was still statistically different from HCs. However, catalase activity was significantly lower only in DM1 patients with increased CK.

Discussion: Undesirable alterations in antioxidant enzyme activities during DM1 disease progression may result in conditions favoring oxidative stress and changes in metabolism which together could contribute to muscle wasting.     

Severe dysfunction of respiratory chain and cholesterol metabolism in Atp7b(-/-) mice as a model for Wilson disease

Wilson disease (WD) is caused by mutations of the WD gene ATP7B resulting in copper accumulation in different tissues. WD patients display hepatic and neurological disease with yet poorly understood pathomechanisms. Therefore, we studied age-dependent (3, 6, 47weeks) biochemical and bioenergetical changes in Atp7b(-/-) mice focusing on liver and brain. Mutant mice showed strongly elevated copper and iron levels. Age-dependently decreasing hepatic reduced glutathione levels along with increasing oxidized to reduced glutathione ratios in liver and brain of 47weeks old mice as well as elevated hepatic and cerebral superoxide dismutase activities in 3weeks old mutant mice highlighted oxidative stress in the investigated tissues. We could not find evidence that amino acid metabolism or beta-oxidation is impaired by deficiency of ATP7B. In contrast, sterol metabolism was severely dysregulated. In brains of 3week old mice cholesterol, 8-dehydrocholesterol, desmosterol, 7-dehydrocholesterol, and lathosterol were all highly increased. These changes reversed age-dependently resulting in reduced levels of all previously increased sterol metabolites in 47weeks old mice. A similar pattern of sterol metabolite changes was found in hepatic tissue, though less pronounced. Moreover, mitochondrial energy production was severely affected. Respiratory chain complex I activity was increased in liver and brain of mutant mice, whereas complex II, III, and IV activities were reduced. In addition, aconitase activity was diminished in brains of Atp7b(-/-) mice. Summarizing, our study reveals oxidative stress along with severe dysfunction of mitochondrial energy production and of sterol metabolism in Atp7b(-/-) mice shedding new light on the pathogenesis of WD.     

Developmental Aspects of Detoxifying Enzymes in Fish (Salmo Iridaeus)

The activities of superoxide dismutase, catalase, glutathione reductase, glutathione peroxidase, glutathione transferase and glyoxalase I have been studied during the embryologic development of rainbow trout (Salmo iridaeus) and in several other trout tissues to investigate the protective development metabolism.

A gradual increase of superoxide dismutase, catalase, glutathione reductase, glyoxalase I and glutathione transferase activities was noted throughout embryo development.

In all trout tissues investigated glutathione peroxidase was found to be extremely low compared to catalase activity. The highest activity of superoxide dismutase, glyoxalase I and glutathione reductase was found in liver followed by kidney.

No change in the number of GST subunits was noted with the transition from the embryonic to the adult stages of life according to the SDS/PAGE and HPLC analyses performed on the GSH-affinity purified fractions.     

Acidosis Potentiates Oxidative Neuronal Death by Multiple Mechanisms

Both acidosis and oxidative stress contribute to ischemic brain injury. The present study examines interactions between acidosis and oxidative stress in murine cortical cultures. Acidosis (pH 6.2) was found to potentiate markedly neuronal death induced by H2O2 exposure. To determine if this effect was mediated by decreased antioxidant capacity at low pH, the activities of several antioxidant enzymes were measured. Acidosis was found to reduce the activities of glutathione peroxidase and glutathione S-transferase by 50-60% (p < 0.001) and the activity of glutathione reductase by 20% (p < 0.01) in lysates of the cortical cultures. Like acidosis, direct inhibition of glutathione peroxidase with mercaptosuccinate also potentiated H2O2 toxicity. Because acidosis may accelerate hydroxyl radical production by the Fenton reaction, the effect of iron chelators was also examined. Both desferrioxamine and N,N,N',N'-tetrakis(2-pyridylmethyl)ethylenediamine, two structurally different iron chelators, significantly reduced H2O2-induced neuronal death under both pH 7.2 and pH 6.2 conditions. These results suggest that the increased cell death produced by severe acidosis during cerebral ischemia may result in part from exacerbation of oxidative injury. This exacerbation may result from both impaired antioxidant enzyme functions and increased intracellular free iron levels.     

The effect ofGongronema latifolium extracts on serum lipid profile and oxidative stress in hepatocytes of diabetic rats

Diabetes is known to involve oxidative stress and changes in lipid metabolism. Many secondary plant metabolites have been shown to possess antioxidant activities, improving the effects of oxidative stress on diabetes. This study evaluated the effects of extracts from Gongronema latifolium leaves on antioxidant enzymes and lipid profile in a rat model of non insulin dependent diabetes mellitus (NIDDM). The results confirmed that the untreated diabetic rats were subjected to oxidative stress as indicated by significantly abnormal activities of their scavenging enzymes (low superoxide dismutase and glutathione peroxide activities), compared to treated diabetic rats, and in the extent of lipid peroxidation (high malondialdehyde levels) present in the hepatocytes. The ethanolic extract of G. latifolium leaves possessed antioxidant activity as shown by increased superoxide dismutase and glutathione peroxidase activities and decreases in malondialdehyde levels. High levels of triglycerides and total cholesterol, which are typical of the diabetic condition, were also found in our rat models of diabetes. The ethanolic extract also significantly decreased triglyceride levels and normalized total cholesterol concentration.     

Plasma selenium decrease during pregnancy is associated with glucose intolerance

There is an increased requirement for selenium during pregnancy, presumably for fetal growth, which manifests as decreasing maternal blood and tissue selenium concentrations. These decreases are greater in pregnant women with gestational or preexisting diabetes. We measured selenium status and glucose tolerance between wk 12 and 34 of gestation in 22 pregnant women. We found that the increase in blood glucose in response to an oral glucose challenge at 12 wk gestation and the increase in fasting glucose during pregnancy were inversely correlated with plasma selenium concentration. Women with lower plasma glutathione peroxidase activities during pregnancy also tended to have higher fasting glucose levels. These inverse relationships between selenium status and glucose tolerance are consistent with earlier observations that suggest a link between selenium and glucose metabolism. The observation that changes in serum glucose were not accompanied by changes in insulin suggests that selenium may affect glucose metabolism downstream from insulin, or through independent energy regulatory pathways such as thyroid hormone.     

Current advances in ischemic stroke research and therapies

With more than 795,000 cases occurring every year, stroke has become a major problem in the United States across all demographics. Stroke is the leading cause of long-term disability and is the fifth leading cause of death in the US. Ischemic stroke represents 87% of total strokes in the US, and is currently the main focus of stroke research. This literature review examines the risk factors associated with ischemic stroke, changes in cell morphology and signaling in the brain after stroke, and the advantages and disadvantages of in vivo and in vitro ischemic stroke models. Classification systems for stroke etiology are also discussed briefly, as well as current ischemic stroke therapies and new therapeutic strategies that focus on the potential of stem cells to promote stroke recovery.