熊果酸对动脉粥样硬化大鼠氧化应激和炎性反应的影响

目的 研究熊果酸(UA)对动脉粥样硬化(AS)大鼠氧化应激和炎性反应的抑制作用,并探讨其机制.方法 采用高脂饲料喂养结合腹腔注射VD3的方法建立早期AS大鼠模型,并分别灌胃给予UA(10、20、40 mg· kg-1· d-1)和辛伐他汀(SV, 1.8 mg· kg-1· d-1)进行干预,作为干预组,另设模型组和健康对照组(喂食正常饲料并腹腔注射生理盐水).采用比色法测定血清中抗氧化酶[超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)、过氧化氢酶(CAT)]活性和丙二醛(MDA)、活性氧簇(ROS)含量;酶联免疫法(ELISA)测定血浆中炎性细胞因子[C反应蛋白(CRP)、肿瘤坏死因子-α(TNF-α)、白细胞介素-1β(IL-1β)、白细胞介素-6(IL-6)、白细胞介素-10(IL-10)]含量;苏木精-尹红(HE)染色观察主动脉形态结构改变并进行病变分级.结果 UA(20、40 mg· kg -1· d-1)同步干预组大鼠血清中 SOD、CAT 活性较模型组显著升高[(318.3 ±29.4)、(12.3 ±2.4)U· mL-1vs(249.3 ±25.1)、(9.3 ±1.7)U· mL-1],MDA、ROS含量显著降低[(31.2 ±5.1)vs(49.6 ±7.0) mmol· L-1和(291.3 ±31.8)vs(402.9 ±35.7)U· mL-1],且UA 40 mg· kg -1· d-1干预组GSH-Px活性显著升高[(809.3 ± 58.4)vs(676.1 ±48.5)U· mL-1];UA(20、40 mg· kg-1· d-1)同步干预组大鼠血浆中CRP、TNF-α、IL-1β、IL-6含量较模型组均显著降低,且UA 40 mg· kg-1· d-1干预组IL-10含量显著升高[(37.6 ±4.9)vs(23.9 ±3.2)ng· L-1];UA同步干预组大鼠主动脉形态结构改变较模型组明显改善、病变评分显著降低,其中以UA 40 mg· kg-1· d-1干预组效果最为显著.结论UA可能通过抑制氧化应激损伤和炎性反应而对AS大鼠起到一定保护作用.     

褪黑素对心力衰竭大鼠心肌细胞凋亡及氧化应激的影响

目的：观察褪黑素（melatonin,MT）对心力衰竭大鼠的心肌细胞凋亡及氧化应激的影响,并初步探讨其影响机制。方法：将52只雄性SD大鼠随机分为3组。MT组及异丙肾上腺素组（ISO组）各20只,对照组12只。MT组及ISO组给予ISO皮下多点注射ISO建立心衰模型,造模成功后MT组给予MT治疗,ISO组不给予MT治疗;对照组不给予任何处置。8周后,随机从各组选取存活大鼠各10只,进行心脏超声检查,并测定心肌组织SOD、GSH-PX活性及MDA的含量;原位末端标记法（TUNEL）检测心肌细胞凋亡指数。结果：与对照组大鼠比较,ISO组及MT组大鼠LVEDD、LVESD明显扩大（P〈0.05或P〈0.01）,LVEF、FS明显降低（P〈0.01）,心肌细胞凋亡指数升高（P〈0.01）,心肌组织MDA含量升高（P〈0.01）,SOD、GSH-Px活性均有显著性下降（P〈0.05或0.01）;与ISO组大鼠比较,MT组大鼠LVEDD、LVESD明显减小（P〈0.05）,LVEF、FS明显增加（P〈0.05）,心肌细胞凋亡指数减低（P〈0.01）,心肌组织MDA含量下降（P〈0.05）,SOD、GSH-Px活性亦有明显升高（P〈0.05）。结论：MT能够改善心力衰竭大鼠心肌组织的氧化应激反应及心肌细胞凋亡,并具有改善心脏功能的作用。     

Green tea protection against age-dependent ethanol-induced oxidative stress

Ethanol intoxication leads to oxidative stress, which may be additionally enhanced by aging. The aim of this study was to investigate the influence of green tea as a source of water-soluble antioxidants on the ability to prevent oxidative stress in aged rats sub-chronically intoxicated with ethanol. Two-, 12-, and 24-mo-old male Wistar rats were divided into 4 experimental groups: (1) control, (2) green tea, (3) ethanol, and (4) ethanol and green tea. Ethanol intoxication produced age-dependent decrease in the activity of serum superoxide dismutase, glutathione peroxidase, and reductase and in levels of glutathione (GSH), vitamins C, E, and A, and beta-carotene. Changes in the serum antioxidative ability were accompanied by enhanced oxidative modification of lipid (increase in lipid hydroperoxides, malondiadehyde, and 4-hydroxynonenal levels) and protein (rise in carbonyl group levels). Green tea partially protected against changes in antioxidant enzymatic as well as nonenzymatic parameters produced by ethanol and enhanced by aging. Administration of green tea significantly protects cellular components such as lipids and proteins against oxidative modification. Results indicate that green tea effectively protects blood serum against oxidative stress produced by ethanol as well as aging.     

太子参对心肌梗死后慢性心衰大鼠氧化应激的干预作用

目的研究太子参对心肌梗死后慢性心衰大鼠氧化应激的干预作用。方法采用结扎大鼠冠状动脉导致急性心肌梗死(AMI)复制慢性心衰大鼠动物模型,以心指数、羟脯氨酸的含量分析心肌纤维化程度,以左心室超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、谷胱甘肽过氧化物酶(GSH-Px)活力与总抗氧化能力(T-AOC)分析抗氧化能力,以丙二醛(MDA)含量分析氧化能力。结果大鼠冠脉结扎导致AMI 6周后,左心室体重指数、羟脯氨酸的含量提示心肌纤维化;左心室SOD、CAT、GSH-Px的活力显著降低、T-AOC水平明显下降,MDA含量显著增加。太子参水煎液连续ig给药5周,可显著降低心脏体重指数和左心室羟脯氨酸的含量;提高抗氧化酶的活力和T-AOC的水平,降低MDA的含量。结论太子参水煎液可改善心肌梗死后的慢性心衰,其机制可能与改善氧化应激状态,提高抗氧化能力,降低MDA的含量相关。     

海兔素对大鼠原代肝细胞酒精性氧化损伤的保护作用

目的探讨海兔素对大鼠原代肝细胞酒精性氧化损伤保护作用。方法门静脉胶原酶Ⅳ原位灌注及密度梯度离心获得大鼠原代肝细胞。MTT实验检测乙醇和海兔素最佳作用剂量及肝细胞活力。酶学实验检测细胞AST、LDH、SOD、MDA、GSH水平;流式细胞术检测细胞凋亡情况;单细胞凝胶电泳观察细胞DNA损伤状况;JC-1荧光探针检测细胞线粒体膜电位水平;比色法及Western blot检测细胞CYP2E1活性及蛋白表达。结果经30 mg·L~(-1)。海兔素预作用2 h,再与300 mmol·L~(-1)。乙醇共作用8 h后,肝细胞活力较酒精模型组明显上升,AST和LDH释放也得到明显抑制;同时,肝细胞SOD和GSH水平明显升高,MDA含量则明显降低,差异均具有显著性(P<0.05)。海兔素干预后,肝细胞凋亡率明显降低,DNA损伤及线粒体膜电位水平明显得到改善。海兔素干预后,肝细胞CYP2E1活性及蛋白表达水平明显受到抑制(P<0.05)。结论海兔素对大鼠原代肝细胞酒精性氧化损伤具有保护作用,其作用机制可能与海兔素抑制酒精对CYP2E1的活化,缓解氧化应激,提高机体抗氧化能力有关。     

Influence of p-coumaric acid on doxorubicin-induced oxidative stress in rat's heart.

The therapeutic value of doxorubicin (DOX) as anticancer antibiotic is limited by its cardiotoxicity. The implication of natural phenolic acids in the prevention of many pathologic diseases has been reported. Herein, the ability of p-coumaric (PC) acid, a member of phenolic acids, to protect rat's heart against DOX-induced oxidative stress was investigated. Three main groups of albino rats were used; DOX, PC, and PC plus DOX-receiving animals. Corresponding control animals were also used. DOX was administered i.p. in a single dose of 15mgkg(-1). PC alone, in a dose of 100mgkg(-1), was orally administered for five consecutive days. In PC/DOX group, rats received PC 5 days prior to DOX. DOX-induced high serum levels of lactic dehydrogenase (LDH) and creatine phosphokinase (CPK), were reduced significantly by PC administration, compared to DOX-receiving rats. Pretreatment with PC ameliorated the cardiac content of glutathione (GSH), and superoxide dismutase (SOD) & catalase (CAT) activities, compared to DOX-receiving rats. On the other hand, accumulation of cardiac content of MDA significantly decreased following PC pretreatment, compared to DOX-treated rats. The data presented here indicate that PC protects rats hearts against DOX-induced oxidative stress in the heart. It may be worthy to consider the usefulness of PC as adjuvant therapy in cancer management.     

Quercetin protects against ethanol-induced oxidative damage in rat primary hepatocytes

The pathogenesis and progression of alcoholic liver disease (ALD) are associated with free radical injury and oxidative stress, which could be partially attenuated by antioxidants and free radical scavengers. Quercetin, one of the most widely distributed flavonoids in plants, is a natural antioxidant. The hypothesis that quercetin could prevent the ethanol-induced oxidative damage in hepatocytes was investigated. The ethanol-intoxicated (100 mM for 8 h) rat primary hepatocytes were post-treated (2 h), simultaneously treated or pre-treated (2 h) with quercetin respectively, while the time-dependent (0.5–8 h) and dose-dependent (25–200 μM) quercetin pre-treatment were used in the present study. The parameters of lactate dehydrogenase (LDH), aspartate transaminase (AST), malondialdehyde (MDA), glutathione (GSH), superoxide dismutase (SOD) and catalase (CAT) were determined to address the alterations of cell damage and antioxidant state after quercetin intervention. The toxic insult of ethanol to hepatocytes was challenged by quercetin and these parameters almost returned to the level of control group when hepatocytes were pre-treated with quercetin at the dose of 50 μM for 2–4 h before ethanol exposure. In conclusion, quercetin pre-treatment provided protection against ethanol-induced oxidative stress in hepatocytes and may be used as a new natural drug for the prevention and/or treatment of ALD.     

Berberine protects liver from ethanol-induced oxidative stress and steatosis in mice

Alcohol consumption is customary in many cultures and it is a common human behavior worldwide. Binge ethanol and chronic alcohol consumption, two usual drinking patterns of human beings, produce a state of oxidative stress in liver and disturb the liver function. However, a safe and effective therapy for alcoholic liver disease in humans is still elusive. This study identified the natural product berberine as a potential agent for treating or preventing ethanol-induced liver injury. We demonstrated that berberine attenuated oxidative stress resulted from binge drinking in liver by reducing hepatic lipid peroxidation, glutathione exhaust and mitochondrial oxidative damage. Furthermore, berberine also prevented the oxidative stress and macrosteatosis in response to chronic ethanol exposure in mice. Either the total cytochrome P450 2E1 or the mitochondria-located cytochrome P450 2E1, which is implicated in ethanol-mediated oxidative stress, was suppressed by berberine. On the other hand, berberine significantly blunted the lipid accumulation in liver due to chronic alcohol consumption, at least partially, through restoring peroxisome proliferator-activated receptor α/peroxisome proliferator-activated receptor-gamma Co-activator-1α and hepatocyte nuclear factor 4α/microsomal triglyceride transfer protein pathways. These findings suggested that berberine could serve as a potential agent for preventing or treating human alcoholic liver disease.     

Effect of ascorbic acid on blood oxidative stress in experimental chronic arsenicosis in rodents

Ascorbic acid is a sugar acid and an essential vital food nutrient found mainly in fruits and vegetables. The purpose of this study was to investigate the effects of ascorbic acid against arsenic induced oxidative stress in blood of rat. In rat, treatment with ascorbic acid prevented the increased serum enzymatic activity of AST, ALT, ALP, ACP and LDH. In addition, treatment with ascorbic acid prevented elevated production of LPO, PC and NO and restored the depletion of reduced SOD and CAT activities. Interestingly, ascorbic acid markedly upregulated lymphocytes relative mRNA expression of lymphocytes SOD2 gene corresponding to GAPDH, house keeping candidate gene in arsenic-treated rat, which might provide anti-oxidative activity in the blood.     

Impact of massive ascorbic acid supplementation on alcohol induced oxidative stress in guinea pigs

The effects of a mega dose of ascorbic acid (AA) on alcohol induced peroxidative damages were investigated in guinea pigs. In the present study, four groups of male guinea pigs were maintained for 30 days as follows. (1) Control group (1 mg AA/100 g body wt); (2) Ethanol group (1 mg AA/100 g body wt. + 9 g ethanol/kg body wt); (3) AA group (25 mg AA/100 g body wt); (4) AA + ethanol group (25 mg AA/100 g body wt. + 9 g ethanol/kg). Results revealed that alcohol induced significant lipid peroxidation, since the lipid peroxidation products malondialdehyde (MDA), hydroperoxides and conjugated dienes were elevated. The activities of scavenging enzymes superoxide dismutase (SOD), catalase were reduced. However, supplementation of AA along with alcohol reduced the lipid peroxidation products in the liver and enhanced the activities of scavenging enzymes. Activities of glutathione peroxidase and reductase were also greater in guinea pigs given alcohol + AA in comparison with those given alcohol alone. Administration of ascorbic acid also reduced the activity of gamma-glutamyl transpeptidase (GGT), the marker enzyme of alcohol induced toxicity. The vitamin E level, which was reduced by alcohol intake, was raised by the co-administration of AA and alcohol. These studies suggest that a mega dose of AA helps in the prevention of alcohol induced oxidative stress by enhancing the antioxidant capacity and also by reducing the lipid peroxidation products.     

Impact of oxidative stress on neuronal survival

1. Reactive oxygen species and oxidative state are slowly gaining acceptance in having a physiological relevance rather than just being the culprits in pathophysiological processes. The control of the redox environment of the cell provides for additional regulation in relation to signal transduction pathways. Conversely, aberrant regulation of oxidative state manifesting as oxidative stress can predispose a cell to adverse outcome. 2. The phosphatidylinositol 3-kinase/akt pathway is one such pathway that is partially regulated via oxidative state and, in an oxidative stress paradigm such as ischaemic-reperfusion injury, may be inactivated, which can lead to exacerbation of cell death. 3. Activation of nuclear factor (NF)-kappaB has been associated with oxidative stress. The role of NF-kappaB in neuronal cell death is widely debated, with major studies highlighting both a pro- and anti-apoptotic role for NF-kappaB, with the outcome being region, stimulus, dose and duration specific. 4. Oxidative state plays a key role in the regulation and control of numerous signal transduction pathways in the cell. Elucidating the mechanisms behind oxidative stress-mediated neuronal cell death is important in identifying potential putative targets for the treatment of diseases such as stroke.     

Role of Nrf2 in preventing ethanol-induced oxidative stress and lipid accumulation

Oxidative stress and lipid accumulation play important roles in alcohol-induced liver injury. Previous reports showed that, in livers of nuclear factor erythroid 2-related factor 2 (Nrf2)-activated mice, genes involved in antioxidant defense are induced, whereas genes involved in lipid biosynthesis are suppressed. To investigate the role of Nrf2 in ethanol-induced hepatic alterations, Nrf2-null mice, wild-type mice, kelch-like ECH-associated protein 1-knockdown (Keap1-KD) mice with enhanced Nrf2, and Keap1-hepatocyte knockout (Keap1-HKO) mice with maximum Nrf2 activation, were treated with ethanol (5 g/kg, po). Blood and liver samples were collected 6 h thereafter. Ethanol increased alanine aminotransferase and lactate dehydrogenase activities as well as thiobarbituric acid reactive substances in serum of Nrf2-null and wild-type mice, but not in Nrf2-enhanced mice. After ethanol administration, mitochondrial glutathione concentrations decreased markedly in Nrf2-null mice but not in Nrf2-enhanced mice. H₂DCFDA staining of primary hepatocytes isolated from the four genotypes of mice indicates that oxidative stress was higher in Nrf2-null cells, and lower in Nrf2-enhanced cells than in wild-type cells. Ethanol increased serum triglycerides and hepatic free fatty acids in Nrf2-null mice, and these increases were blunted in Nrf2-enhanced mice. In addition, the basal mRNA and nuclear protein levels of sterol regulatory element-binding protein 1(Srebp-1) were decreased with graded Nrf2 activation. Ethanol further induced Srebp-1 mRNA in Nrf2-null mice but not in Nrf2-enhanced mice. In conclusion, Nrf2 activation prevented alcohol-induced oxidative stress and accumulation of free fatty acids in liver by increasing genes involved in antioxidant defense and decreasing genes involved in lipogenesis.     

Caffeic acid phenethyl ester modulates methotrexate-induced oxidative stress in testes of rat

The aim of this study was to investigate the possible protective role of caffeic acid phenethyl ester on testicular toxicity of methotrexate in rats. Nineteen male rats were divided into three groups as follows: group I, control; group II, methotrexate-treated; group III, methotrexate + caffeic acid phenethyl ester-treated. In the second day of experiment, a single dose of methotrexate was intraperitoneally administered to groups II and III, although a daily single dose of caffeic acid phenethyl ester was intraperitoneally administered to group III for 7 days. At the end of the experiment, the testes of the animals were removed and weighed. In the tissue, the level of lipid peroxidation as malondialdehyde and activities of superoxide dismutase were higher in the methotrexate group than in the control group. Lipid peroxidation levels and superoxide dismutase activities were decreased in caffeic acid phenethyl ester + methotrexate group compared with methotrexate group. The activities of catalase in the methotrexate group decreased insignificantly although its activities were significantly increased by caffeic acid phenethyl ester administration. The activity of glutathione peroxidase did not change in the groups. There was significant difference in body weight between control and methotrexate-induced groups. In conclusion, the administration of methotrexate causes elevation of oxidative stress although treatment with caffeic acid phenethyl ester has protective effects on the oxidative stress in testes.     

Ellagic acid prevents cisplatin-induced oxidative stress in liver and heart tissue of rats

Cisplatin is one of the most active cytotoxic agents in the treatment of cancer. High doses of cisplatin have also been known to produce hepatotoxicity, and several studies suggest that supplemental antioxidants can reduce cisplatin-induced hepatotoxicity. The present study was designed to determine the effects on the liver and heart oxidant/antioxidant system and the possible protective effects of ellagic acid on liver and heart toxicity induced by cisplatin. The control group received 0.9% saline; animals in the ellagic acid group received only ellagic acid (10 mg/kg); animals in the cisplatin group received only cisplatin (7 mg/kg); animals in cisplatin + ellagic acid group received ellagic acid for 10 days after cisplatin. The rats were killed at the end of the treatment period. Malondialdehyde (MDA) and glutathione (GSH) levels, glutathione-peroxidase (GSH-Px) and catalase (CAT) activities were determined in liver and heart tissue. While administration of cisplatin increased the MDA levels in liver and heart tissues, it decreased the GSH, GSH-Px and CAT in these samples when compared to the control group. The administration of ellagic acid to cisplatin-treated rats decreased the MDA levels, and increased GSH, GSH-Px and CAT in these samples. Cisplatin caused marked damages in the histopathological status of liver and heart tissues. These damages were ameliorated by ellagic acid administration. In conclusion, ellagic acid may be used in combination with cisplatin in chemotherapy to improve cisplatin-induced oxidative stress parameters.     

阿托伐他汀对慢性心衰患者NT-proBNP水平及氧化应激状态的影响

目的 探讨阿托伐他汀对慢性心衰患者NT-proBNP水平及氧化应激状态的影响。方法 选择2015年9月—2017年2月非缺血性心脏病慢性心衰患者102例,将所有患者随机分为对照组（n=51）和阿托伐他汀组（n=51）。对照组实施常规抗心衰药物治疗,阿托伐他汀组在常规抗心衰治疗基础上加用阿托伐他汀治疗,20 mg/d。两组疗程均为24周。观察并比较两组治疗前后三酰甘油（TG）、总胆固醇（TC）、高密度脂蛋白（HDL-C）、低密度脂蛋白（LDL-C）、NYHA分级、左室射血分数（LVEF）、NT-proBNP、6 min步行距离（6MWT）、超氧化物歧化酶（SOD）、髓过氧化物酶（MPO）、丙二醛（MDA）等指标。结果 阿托伐他汀组治疗后TG、TC、LDL-C水平明显下降,与治疗前及对照组比较,差异均有统计学意义（P<0.05）。两组患者治疗后NT-proBNP水平均有明显下降,与治疗前比较,差异有统计学意义（P<0.05）,但阿托伐他汀组下降幅度优于对照组,组间比较差异有统计学意义（P<0.05）。与同组治疗前及对照组比较,阿托伐他汀组治疗后SOD明显增高,MDA、MPO明显下降,差异均有统计学意义（P<0.05）;而对照组治疗前后无明显变化。结论 在常规抗心衰治疗的基础上加用阿托伐他汀,能有效降低CHF患者的NT-proBNP水平和抑制患者的氧化应激状态。     

d-α-生育酚对乙醇引发的肝脏氧化应激的影响

目的观察d-α-生育酚对乙醇诱发的小鼠肝脏氧化应激的影响并探讨其机制。方法昆明种小鼠每天给予2.4g.kg-1bw乙醇后,再给予3个不同剂量的d-α-生育酚(25、50、100mg·kg-1bw.d-1),同时设正常对照组和乙醇对照组(乙醇2.4g·kg-1bw.d-1),连续灌胃60d后,测定肝脏超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)、Na+,K+-ATP酶(Na+,K+-ATPase)、Ca2+,Mg2+-ATP酶(Ca2+,Mg2+-ATPase)、谷胱甘肽-S转移酶(GST)活力及丙二醛(MDA)的含量。结果小鼠摄入乙醇60d后,肝脏氧化应激水平明显增高。除Ca2+,Mg2+-ATPase以外,其余各项指标与正常对照组相比,差异均有显著性(P<0.05)。50mg·kg-1bw.d-1d-α-生育酚干预后,与乙醇对照组相比,GSH-Px、SOD、GST、Na+,K+-ATPase活力明显升高,MDA含量显著下降。其中,GSH-Px、Na+,K+-ATPase、MDA等3个指标在25mg·kg-1bw.d-1d-α-生育酚干预时亦出现同样的变化。结论适宜剂量的d-α-生育酚可以通过直接抑制脂质过氧化对乙醇诱发的肝脏氧化应激起保护作用。     

High fat diet aggravates arsenic induced oxidative stress in rat heart and liver

Arsenic is a well known global groundwater contaminant. Exposure of human body to arsenic causes various hazardous effects via oxidative stress. Nutrition is an important susceptible factor which can affect arsenic toxicity by several plausible mechanisms. Development of modern civilization led to alteration in the lifestyle as well as food habits of the people both in urban and rural areas which led to increased use of junk food containing high level of fat. The present study was aimed at investigating the effect of high fat diet on heart and liver tissues of rats when they were co-treated with arsenic. This study was established by elucidating heart weight to body weight ratio as well as analysis of the various functional markers, oxidative stress biomarkers and also the activity of the antioxidant enzymes. Histological analysis confirmed the biochemical investigations. From this study it can be concluded that high fat diet increased arsenic induced oxidative stress.     

Aldosterone and the autocrine modulation of potassium currents and oxidative stress in the diabetic rat heart

BACKGROUND AND PURPOSE: Aldosterone plays a major role in cardiac pathology. This study was designed to investigate the role of cardiac aldosterone in modulating K(+) currents and oxidative stress in the streptozotocin-induced diabetic rat heart. EXPERIMENTAL APPROACH: Transient and sustained K(+) currents were measured in ventricular myocytes by voltage clamp. Plasma and cellular aldosterone were measured by ELISA. Fluorescent dihydroethidium (DHE) was used to assess superoxide ions as markers of oxidative stress. KEY RESULTS: The mineralocorticoid antagonist spironolactone (1 microM, 5-9 h) significantly augmented both K(+) currents in diabetic males, with a concomitant shortening of the action potential but had no effect in myocytes from control males or from diabetic females. Effects of spironolactone were restored in ovariectomized diabetic females and abolished in orchidectomized diabetic males. The aldosterone synthase inhibitor FAD286 (1 microM, 5-9 h) significantly augmented K(+) currents in cells from diabetic males, but not females. Spironolactone and FAD286 significantly reduced oxidative stress in cells from diabetic males. Plasma aldosterone content was elevated in diabetic males (relative to control), but not in females. Cellular aldosterone was also elevated, but not significantly. The elevation in aldosterone was only partly dependent on a concomitant increase in cellular angiotensin II. CONCLUSIONS AND IMPLICATIONS: A gender-related, sex-hormone-dependent elevation in plasma and cardiac cell aldosterone contributed to oxidative stress and to attenuation of K(+) currents in diabetic male rats. Aldosterone may thus contribute to diabetes-associated cardiac arrhythmias. Aldosterone elevation was partly related to levels of angiotensin II, but residual, angiotensin II-independent, aldosterone maintains functional relevance.     

Studies on paraquat-induced oxidative stress in rat liver

Oxidative injury of liver was studied 20 hr after a single oral administration of 150 mg/kg paraquat (PQ) to rats. PQ exerted no effect on cytosolic superoxide dismutase (SOD) activity but increased mitochondrial SOD activity by 14%. The level of GSH was decreased by 30%, and GSH/GSSG ratio was diminished almost twice. The correlation between the enhancement of mitochondrial SOD activity and the diminution of GSH level by PQ implicates O2- in the liver toxicity of the drug. Mitochondrial aconitase activity was slightly decreased (by 9%) while cytosolic aconitase activity was not affected. The results cast additional light on the responses of both aconitases to oxidative stress.