Activation of Akt kinase accompanies increased cardiac resistance to ischemia/reperfusion in rats after short-term feeding with lard-based high-fat diet and increased sucrose intake

High-fat or high-carbohydrate food consumption contributes to changes in myocardial tolerance to ischemia. However, with respect to experimental models, most studies used diets with very high doses of cholesterol, saturated fatty acids, or fructose. In our study, we fed rats a high-fat diet based on lard in combination with administration of a sweet beverage (30% sucrose solution) (high-fat sucrose diet [HFS]). This diet was used to simulate the unhealthy dietary habit typical for developed countries. We hypothesized that the application of HFS diet for 48 days might initiate progression of pathologic changes in the heart associated with myocardial remodeling and activation of adaptive mechanisms. We investigated the influence of HFS diet on cardiac function and vulnerability to ischemia-reperfusion (I/R) injury in Langendorff-perfused rat hearts subjected to 30-minute global ischemia and 120-minute reperfusion as well as on Akt kinase and matrix metalloproteinases. We found lower food consumption in HFS group compared with controls, but a significant increase in visceral fat mass and concentrations of triacylglycerol, low-density lipoprotein, and very low-density lipoprotein cholesterol. Baseline heart functional parameters and their postischemic recovery were not affected by HFS diet. On the other hand, hearts of HFS group were more resistant to lethal I/R injury manifested by significantly smaller infarct size. In addition, there was lower content of collagen I and III in the left ventricle associated with Akt kinase activation and matrix metalloproteinase 9 up-regulation. In conclusion, feeding rats with HFS diet resulted in heart remodeling associated with activation of some adaptive mechanisms, which can contribute to modulation of myocardial resistance to I/R injury.     

Dietary green tea extract increases phase 2 enzyme activities in protecting against myocardial ischemia-reperfusion

Green tea catechins are dietary antioxidant compounds that have been shown to protect against myocardial ischemia-reperfusion (IR) injury. Considering reports that catechins can induce phase 2 enzymes in cultured cells and some organs, we hypothesized that part of the protection to heart against IR injury may involve elevation of phase 2 enzyme activities. Rats were fed for 10 days with either control diet (sham and control groups) or the diet mixed with 0.25% green tea extract. At the end of 10 days, hearts were excised and subjected to global ischemia for 20 min followed by reperfusion for 2 hours. The hearts were compared for indices of cell death, oxidative stress, and phase 2 enzyme activities. Hearts from the green tea group had a 65% to 85% decrease in markers of apoptosis, a tendency to higher total glutathione, and higher activities of the phase 2 enzymes glutamate cysteine ligase and quinone reductase. The results support a possible involvement of phase 2 enzymes in the protection by green tea catechins against myocardial IR injury.     

Ras蛋白在Lovastatin预适应心肌保护中的作用及其机制的研究

目的研究Ras蛋白在洛伐他汀（Lovastatin）预适应心肌保护中的作用机制。方法将24只Sprague-Dawley（SD）大鼠随机分为3组（n=8）：模型对照组（C）;洛伐他汀（Lovastatin）组（L）,胃管直接灌注洛伐他汀15mg／（kg·d）2周;洛伐他汀（Lovastatin）复合L-硝基精氨酸甲酯（L-NAME）组（N）,洛伐他汀15mg／（kg·d）直接灌注2周同时腹腔注射L-NAME 30mg／（kg·d）;2周后建立在体急性缺血再灌注心脏模型,观察心肌组织Ras-GTPase蛋白表达以及心肌细胞凋亡情况。结果洛伐他汀预适应明显抑制缺血再灌注时期心肌组织Ras-GTPase蛋白表达（t=2．32,P〈0．05）,并且减少缺血再灌注导致的心肌细胞的凋亡数（t=2．25,P〈0．05）。加用NO非选择性抑制性抑制剂L-NAME不影响上述结果。结论洛伐他汀（Lovastatin）预适应对大鼠心脏急性缺血再灌注时具有延迟性心肌保护作用。抑制Ras-GTPase蛋白表达及其信号传导可能是其心肌保护作用的机制,并且此心肌保护作用与NO无关。     

Dietary red palm oil supplementation protects against the consequences of global ischemia in the isolated perfused rat heart

Activation of the NO-cGMP pathway is associated with myocardial protection against ischemia. During ischemia, function of this pathway is disturbed. Little is known about the effects of supplements such as Red Palm Oil (RPO) on the myocardial NO- cGMP- signalling pathway. RPO consists of saturated (SFAs), mono-unsaturated (MUFAs) and polyunsaturated (PUFAs) fatty acids and is an antioxidant rich in natural B-carotene and vitamin E (tocopherols and tocotrienols). This study determined whether dietary RPO-supplementation protects against the consequences of ischemia and identified a possible mechanism for this protection. Long-Evans rats were fed a control diet or control diet plus 7 g RPO per kg diet for six weeks. Hearts were excised and mounted on a working heart perfusion apparatus. Cardiac function was measured before and after hearts were subjected to 25 minutes of global ischemia. Left ventricular systolic (LVSP) and diastolic pressure (LVDP), coronary flow (CF), heart rate (HR) and aortic output (AO) were measured. To assess NO-cGMP pathway activity, hearts subjected to the same conditions, were freeze-clamped and analysed for tissue cAMP and cGMP levels using a RIA method. Furthermore, composition of myocardial phospholipid fatty acids by gas chromatography and blood samples were collected for serum lipid determinations. The percentage aortic output recovery of hearts supplemented with RPO was 72.9 +/-3.43% vs 55.4 +/-2.48% for controls (P< 0.05). Ten minutes into ischemia the cGMP levels of the RPO-supplementation group were significantly higher than the control group (26.5+/-2.78 pmol/g vs 10.1+/-1.78 pmol/g. Total myocardial PUFA content in hearts supplemented with RPO increased from 54.45+/-1.11% before ischemia to 59.03 +/- 0.30% after ischemia P<0.05). Results demonstrated that RPO-supplementation protected hearts against the consequences of ischemia/reperfusion injury. These findings suggest that dietary RPO protects via the NO-cGMP pathway and/or changes in PUFA composition during ischemia/reperfusion.     

S-allyl cysteine mitigates oxidative damage and improves neurologic deficit in a rat model of focal cerebral ischemia

Oxidative stress and inflammatory damage play an important role in cerebral ischemic pathogenesis and may represent a target for treatment. The present study examined the hypothesis that S-allyl cysteine (SAC), organosulfur compounds found in garlic extract, would reduce oxidative stress–associated brain injury after middle cerebral artery occlusion (MCAO). To test this hypothesis, male Wistar rats were subjected to MCAO for 2 hours and 22-hour reperfusion. S-allyl cysteine was administered (100 mg/kg, b.wt.) intraperitoneally 30 minutes before the onset of ischemia and after the ischemia at the interval of 0, 6, and 12 hours. After 24 hours of reperfusion, rats were tested for neurobehavioral activities and were killed for the infarct volume, estimation of lipid peroxidation, glutathione content, and activity of antioxidant enzymes (glutathione peroxidase, glutathione reductase, catalase, and superoxide dismutase). S-allyl cysteine treatment significantly reduced ischemic lesion volume, improved neurologic deficits, combated oxidative loads, and suppressed neuronal loss. Behavioral and biochemical alterations observed after MCAO were further associated with an increase in glial fibrillary acidic protein and inducible nitric oxide expression and were markedly inhibited by the treatment with SAC. The results suggest that SAC exhibits exuberant neuroprotective potential in rat ischemia/reperfusion model. Thus, this finding of SAC-induced adaptation to ischemic stress and inflammation could suggest a novel avenue for clinical intervention during ischemia and reperfusion.     

Dietary (n-3) long-chain polyunsaturated fatty acids inhibit ischemia and reperfusion arrhythmias and infarction in rat heart not enhanced by ischemic preconditioning

Ischemic preconditioning (IPC) and (n-3) PUFA are both cardioprotective. This study compared effects of dietary fish oil, IPC, and their interactions on heart function and injury during myocardial ischemia and reperfusion. Male Wistar rats were fed diets containing 10% wt:wt fat comprising either 7% high-docosahexaenoic acid (DHA) [22:6(n-3)] tuna fish oil + 3% olive oil [(n-3) PUFA]; 5% sunflower seed oil + 5% olive oil [(n-6) PUFA]; or 7% beef tallow + 3% olive oil [saturated fat (SF)] for 6 wk. In control experiments, isolated perfused hearts were subjected to 30-min regional ischemia and reperfused for 120 min. The IPC hearts were subjected to 3 cycles of 5-min global ischemia before the ischemia and reperfusion. Control (n-3) PUFA hearts had significantly lower heart rate, coronary flow, end diastolic pressure, maximum relaxation rate, and ischemic and reperfusion arrhythmias. In reperfusion, they had greater developed pressure and maximum relaxation rate and smaller infarct (10.9 +/- 0.6% ischemic zone, n = 6) than (n-6) PUFA (47.4 +/- 0.3%, n = 6) or SF (50.3 +/- 0.3%, n = 6). Compared with control, IPC significantly improved heart function and reduced infarct in (n-6) PUFA (11.8 +/- 0.4%, n = 6) and SF hearts (13.1 +/- 0.1%, n = 6). Heart function and infarct [(n-3) PUFA 9.6 +/- 0.1%, n = 6] did not differ among dietary IPC groups. Arrhythmias, significantly reduced by IPC in (n-6) PUFA and SF hearts, were significantly lower in (n-3) PUFA IPC hearts. Dietary fish oil induces a form of preconditioning, nutritional preconditioning, limiting ischemic cardiac injury, and myocardial infarction and endows cardioprotection as powerful as IPC, which provides no additional protection in (n-3) PUFA hearts.     

Inhibitory effects of Doenjang,Korean traditional fermented soybean paste,on oxidative stress and inflammation in adipose tissue of mice fed a high-fat diet

BACKGROUND/OBJECTIVES

Doenjang, Korean traditional fermented soybean paste has been reported to have an anti-obesity effect. Because adipose tissue is considered a major source of inflammatory signals, we investigated the protective effects of Doenjang and steamed soybean on oxidative stress and inflammation in adipose tissue of diet-induced obese mice.

MATERIALS/METHODS

Male C57BL/6J mice were fed a low fat diet (LF), a high-fat diet (HF), or a high-fat containing Doenjang diet (DJ) or a high-fat containing steamed soybean diet (SS) for 11 weeks.

RESULTS

Mice fed a DJ diet showed significantly lower body and adipose tissue weights than those in the HF group. Although no significant differences in adipocyte size and number were observed among the HF diet-fed groups, consumption of Doenjang alleviated the incidence of crown-like structures in adipose tissue. Consistently, we observed significantly reduced mRNA levels of oxidative stress markers (heme oxygenase-1 and p40^phox), pro-inflammatory adipokines (tumor necrosis factor alpha and macrophage chemoattractant protein-1), macrophage markers (CD68 and CD11c), and a fibrosis marker (transforming growth factor beta 1) by Doenjang consumption. Gene expression of anti-inflammatory adipokine, adiponectin was significantly induced in the DJ group and the SS group compared to the HF group. The anti-oxidative stress and anti-inflammatory effects observed in mice fed an SS diet were not as effective as those in mice fed a DJ diet, suggesting that the bioactive compounds produced during fermentation and aging may be involved in the observed health-beneficial effects of Doenjang.

CONCLUSIONS

Doenjang alleviated oxidative stress and restored the dysregulated expression of adipokine genes caused by excess adiposity. Therefore, Doenjang may ameliorate systemic inflammation and oxidative stress in obesity via inhibition of inflammatory signals of adipose tissue.     

Green tea polyphenols benefits body composition and improves bone quality in long-term high-fat diet–induced obese rats

This study investigates the effects of green tea polyphenols (GTPs) on body composition and bone properties along with mechanisms in obese female rats. Thirty-six 3-month-old Sprague Dawley female rats were fed either a low-fat (LF) or a high-fat (HF) diet for 4 months. Animals in the LF diet group continued on an LF diet for additional 4 months, whereas those in the HF diet group were divided into 2 groups: with GTP (0.5%) or without in drinking water, in addition to an HF diet for another 4 months. Body composition, femur bone mass and strength, serum endocrine and proinflammatory cytokines, and liver glutathione peroxidase (GPX) protein expression were determined. We hypothesized that supplementation of GTP in drinking water would benefit body composition, enhance bone quality, and suppress obesity-related endocrines in HF diet–induced obese female rats and that such changes are related to an elevation of antioxidant capacity and a reduction of proinflammatory cytokine production. After 8 months, compared with the LF diet, the HF diet increased percentage of fat mass and serum insulin–like growth factor I and leptin levels; reduced percentage of fat-free mass, bone strength, and GPX protein expression; but had no effect on bone mineral density and serum adiponectin levels in the rats. Green tea polyphenol supplementation increased percentage of fat-free mass, bone mineral density and strength, and GPX protein expression and decreased percentage of fat mass, serum insulin–like growth factor I, leptin, adiponectin, and proinflammatory cytokines in the obese rats. This study shows that GTP supplementation benefited body composition and bone properties in obese rats possibly through enhancing antioxidant capacity and suppressing inflammation.     

Glutamine restores myocardial cytochrome C oxidase activity and improves cardiac function during experimental sepsis

Background: Cardiac dysfunction occurs commonly in sepsis. Impaired mitochondrial function is a potential cause of sepsis‐associated myocardial depression. Cytochrome oxidase (COX), the terminal oxidase of the electron transport chain, is inhibited in the septic heart. Glutamine (GLN) increases Krebs cycle intermediates and supports oxidative phosphorylation. Exogenous GLN has been shown to restore myocardial adenosine triphosphate levels and cardiac function following ischemia–reperfusion injury. The authors hypothesize that exogenous GLN will abrogate sepsis‐induced myocardial COX inhibition and improve sepsis‐associated myocardial depression. Methods: Under general anesthesia, male Sprague‐Dawley rats underwent cecal ligation and double puncture (CLP) or sham operation. At the time of operation, rats underwent intraperitoneal injection of either GLN (0.75 g/kg) or an equal volume of saline. Twenty‐four hours after the procedure, animals were killed, cardiac ventricles harvested, and mitochondria isolated. Steady‐state COX kinetic activity was measured and normalized to citrate synthase activity. Steady‐state levels of COX subunit I protein were determined with immunoblot analysis. Cardiac function was assessed using an isolated rat heart preparation. Five animals per group were evaluated. Significance was determined with analysis of variance and post hoc Tukey test. Results: CLP significantly decreased myocardial COX activity, oxygen consumption, left ventricular pressure (LVP), and pressure developed during isovolumic contraction (+dP/dt) and relaxation (?dP/dt). GLN restored COX activity to sham levels, significantly increased myocardial oxygen extraction and consumption, increased LVP toward sham values, and increased ±dP/dt by >30% following CLP. Conclusion: The beneficial effects of GLN therapy during sepsis may be in part due to restoration of oxidative phosphorylation and abrogation of sepsis‐associated myocardial depression.     

内源性神经激肽和降钙素基因相关肽在大鼠心肌缺血后适应对心肌超氧化物歧化酶的作用

目的：研究神经激肽1（NK1）、降钙素基因相关肽（CGRP）在大鼠缺血后适应对心肌超氧化物歧化酶（SOD）的作用。方法：随机将SD雄性大鼠（350~400g）分为5组：sham组（只穿线不结扎冠状动脉）、I/R组（结扎冠状动脉左前降支30min,再灌注120min）、ipost组（结扎冠状动脉左前降支30min,再灌注10s夹闭10s,如此反复3次后持续再灌注120min）、CGRP8-37＋ipost组（结扎冠状动脉左前降支25min,按1μg/kg剂量从尾静脉给药CGRP8-37,5min行后处理再灌注同ipost组）、D-SP＋ipost组（结扎冠状动脉左前降支25min,按1μg/kg剂量从尾静脉给药D-SP,5min行后处理再灌注同ipost组）;快速液氮冷冻各组缺血心肌组织并提取心肌总蛋白,行总蛋白定量,用酶联免疫吸附技术检测心肌SOD的表达,分光光度法检测Caspase-3活性。结果：（1）与sham组比较,I/R组Caspase-3、SOD均增多（P〈0.01）;（2）与I/R组比较,ipost组SOD增多（P〉0.05）,Caspase-3减少（P〈0.01）;（3）与ipost组比较：CGRP8-37＋ipost组SOD降低（P〈0.01）,Caspase-3增多（P〉0.05）,D-SP＋ipost组SOD降低（P〈0.01）,Caspase-3增多（P〉0.05）。结论：神经激肽1降钙素基因相关肽（CGRP）通过上调缺血心肌SOD表达对缺血后适应心肌起保护作用。     

香草乙酮对大鼠心肌再灌注损伤的保护作用

目的为明确烟酰胺腺嘌呤二核苷酸磷酸(NADPH)氧化酶在心肌再灌注损伤中的作用,并探索治疗再灌注损伤的新途径,使用香草乙酮(apocynin)这一特异的NADPH氧化酶抑制剂对心肌再灌注损伤进行干预,并对其效果和机制进行了观察分析。方法使用在体大鼠心脏缺血再灌注模型,给予30 min左前降支结扎造成缺血,随后松扎进行3 h再灌注。Apocynin干预组于再灌注前10 min给予不同剂量的apocynin,观察其剂量与心脏保护效应关系,并测定心功能、梗死面积、心肌细胞凋亡、NADPH氧化酶活性和自由基生成等指标。结果再灌注后心肌NADPH氧化酶活性明显升高,自由基生成也显著增加。给予apocynin可剂量依赖性地减轻心肌再灌注引起的细胞凋亡和自由基生成,apocynin 10 mg/kg剂量可以改善再灌注后的心脏功能,缩小梗死面积,减少心肌凋亡的发生,抑制NADPH氧化酶的活化,从而减少超氧阴离子和过氧化亚硝酸盐自由基的生成及其损伤,但对一氧化氮的生成无明显影响。结论NADPH氧化酶在心肌再灌注损伤中发挥重要作用,apocynin可以对再灌注大鼠心肌发挥保护作用,这种保护与其抑制NADPH氧化酶的活性,减少其介导的超氧阴离子和过氧化亚硝酸盐自由基生成有关。     

大鼠心肌缺血再灌注损伤与HSP70的关系及三七总皂甙对其保护作用的机理研究

目的通过检测HSP70在心肌中的表达,探讨心肌缺血再灌注与HSP70之间的关系以及三七总皂甙对缺血再灌注心肌保护作用的机制。方法Wistar大鼠60只,随机分为4组空白组、缺血再灌注组、PNS组(三七总皂甙组)和热处理组。PNS组(n=15)腹辣腔注射PNS150mg/kg,每日一次,连续7d;热处理组(n=15)给予热休克预处理,然后除空白组外,均采用在体缺血再灌注模型造模。缺血40min再灌注120min后检测血清CK和心肌HSP70表达水平,并同时作心肌组织病理切片和免疫组化观察。结果缺血再灌注组、PNS组和热处理组心肌HSP70表达均明显升高,PNS组和热处理组血清CK水平显著低于缺血再灌注组,病理切片亦显示相同趋势。结论HSP70在缺血再灌注心肌中呈高诱导表达,可能可以作为衡量心肌缺血再灌注损伤程度的重要指标,PNS和热休克预处理均对缺血再灌注心肌有良好的保护作用,PNS的保护作用可能与HSP70表达有关。     

Ischemic preconditioning: protection against myocardial necrosis and apoptosis

The phenomenon of ischemic preconditioning has been recognized as one of the most potent mechanisms to protect against myocardial ischemic injury. In experimental animals and humans, a brief period of ischemia has been shown to protect the heart from more prolonged episodes of ischemia, reducing infarct size, attenuating the incidence, and severity of reperfusion-induced arrhythmias, and preventing endothelial cell dysfunction. Although the exact mechanism of ischemic preconditioning remains obscure, several reports indicate that this phenomenon may be a form of receptor-mediated cardiac protection and that the underlying intracellular signal transduction pathways involve activation of a number of protein kinases, including protein kinase C, and mitochondrial K(ATP) channels. Apoptosis, a genetically programmed form of cell death, has been associated with cardiomyocyte cell loss in a variety of cardiac pathologies, including cardiac failure and those related to ischemia/reperfusion injury. While ischemic preconditioning significantly reduces DNA fragmentation and apoptotic myocyte death associated with ischemia-reperfusion, the potential mechanisms underlying this effect have not been fully clarified. A comprehensive understanding of these mechanisms and application to clinical scenarios will provide new directions in research and translate this information into new treatment approaches for reducing the extent of ischemia/reperfusion injury.     

Synthesis and biological evaluation of 5-membered spiro heterocycle-benzopyran derivatives against myocardial ischemia

The activation of ATP-sensitive potassium channels (K_ATP), play a key role in an endogenous “self-defence” mechanism, known as ischemic preconditioning (IPC), which is fundamentally involved in the protection of the heart against the ischemia/reperfusion injury. Presently, it is widely accepted that IPC is mainly (albeit not exclusively) mediated by the activation of K_ATP channels expressed in the mitochondrial inner membrane (mito-K_ATP) rather than the sarcoplasmatic ones (sarc-K_ATP). Consistently, exogenous activation of K_ATP channels by pharmacological tools can be viewed as one of the most promising strategies for the therapy of myocardial ischemia. As part of our research program devoted to the synthesis and the evaluation of new cardioprotective agents, we extensively studied several six-membered spiro-heterocycle-benzopyran compounds endowed of a significant anti-ischemic activity. The positive results obtained, prompted us to further explore the influence on the biopharmacological effects, of the spiro-substitution at C4 benzopyran nucleus by replacing the six-membered spirocycle of the most active compounds with 5-membered-one.The preliminary evaluation of the new compounds on cultured H9c2 cardiomyoblasts exposed to anoxia/reperfusion and on Langendorff-perfused rat hearts submitted to ischemia/reperfusion cycles, showed that some of them can exert a cardioprotective effect. This anti-ischemic activity was antagonized by 5-hydroxydecanoic acid, a selective blocker of mito-K_ATP channels, confirming the involvement of this channel in the cardioprotective activity.     

Phycocyanin prevents hypertension and low serum adiponectin level in a rat model of metabolic syndrome

Endothelial dysfunction is associated with hypertension, atherosclerosis, and metabolic syndrome. Phycocyanin is a pigment found in the blue-green algae, Spirulina, which possesses antihypertensive effect. In this study, we hypothesized that phycocyanin derived from Spirulina exerts antihypertensive actions by improving endothelial dysfunction in metabolic syndrome. Spontaneously hypertensive/NIH-corpulent (SHR/NDmcr-cp) rats were divided into 4 groups then fed a normal diet with or without phycocyanin (2500-, 5000-, or 10?000-mg/kg diet) for 25 weeks. At 34 weeks of age, although systolic blood pressure was not significantly different among groups, phycocyanin-fed groups exhibited a dose-dependent decrease in blood pressure. Serum levels of adiponectin and messenger RNA levels of adiponectin and CCAAT/enhancer-binding protein α in the adipose tissue of rats fed diets containing phycocyanin tended to be higher than those of rats fed a normal diet, but the differences were not statistically significant. Immunohistochemistry analysis showed a significant and positive correlation between aortic endothelial nitric oxide synthase (eNOS) expression levels, a downstream target of the adiponectin receptor, and serum adiponectin levels, although there were no significant differences in eNOS expression among groups. There was also no significant correlation between eNOS expression levels and systolic blood pressure. These results suggest that long-term administration of phycocyanin may ameliorate systemic blood pressure by enhancing eNOS expression in aorta that is stimulated by adiponectin. Phycocyanin may be beneficial for preventing endothelial dysfunction-related diseases in metabolic syndrome.     

Effects of cranberry powder on biomarkers of oxidative stress and glucose control in db/db mice

Increased oxidative stress in obese diabetes may have causal effects on diabetic complications, including dyslipidemia. Lipopolysccharides (LPS) along with an atherogenic diet have been found to increase oxidative stress and insulin resistance. Cranberry has been recognized as having beneficial effects on diseases related to oxidative stress. Therefore, we employed obese diabetic animals treated with an atherogenic diet and LPS, with the aim of examining the effects of cranberry powder (CP) on diabetic related metabolic conditions, including lipid profiles, serum insulin and glucose, and biomarkers of oxidative stress. Forty C57BL/KsJ-db/db mice were divided into the following five groups: normal diet + saline, atherogenic diet + saline, atherogenic diet + LPS, atherogenic diet + 5% CP + LPS, and atherogenic diet + 10% CP + LPS. Consumption of an atherogenic diet resulted in elevation of serum total cholesterol and atherogenic index (AI) and reduction of high density lipoprotein (HDL)-cholesterol. However, with 10% CP, the increase in mean HDL-cholesterol level was close to that of the group with a normal diet, whereas AI was maintained at a higher level than that of the group with a normal diet. LPS induced elevated serum insulin level was lowered by greater than 60% with CP (P < 0.05), and mean serum glucose level was reduced by approximately 19% with 5% CP (P > 0.05). Mean activity of liver cytosolic glutathione peroxidase was significantly increased by LPS injection, however it was reduced back to the value without LPS when the diet was fortified with 10% CP (P < 0.05). In groups with CP, a reduction in mean levels of serum protein carbonyl tended to occur in a dose dependent manner. Particularly with 10% CP, a reduction of approximately 89% was observed (P > 0.05). Overall results suggest that fortification of the atherogenic diet with CP may have potential health benefits for obese diabetes with high oxidative stress, by modulation of physical conditions, including some biomarkers of oxidative stress.     

Acute exposure to high-fat diets increases hepatic expression of genes related to cell repair and remodeling in female rats

High-fat diets (HFD) promote the development of both obesity and fatty liver disease through the up-regulation of hepatic lipogenesis. Insulin resistance, a hallmark of both conditions, causes dysfunctional fuel partitioning and increases in lipogenesis. Recent work has demonstrated that systemic insulin resistance occurs in as little as the first 72 hours of an HFD, suggesting the potential for hepatic disruption with HFD at this time point. The current study sought to determine differences in expression of lipogenic genes between sexes in 3-month-old male and female Long-Evans rats after 72 hours of a 40% HFD or a 17% fat (chow) diet. Owing to the response of estrogen on hepatic signaling, we hypothesized that a sexual dimorphic response would occur in the expression of lipogenic enzymes, inflammatory cytokines, apoptotic, and cell repair and remodeling genes. Both sexes consumed more energy when fed an HFD compared with their low fat–fed controls. However, only the males fed the HFD had a significant increase in body fat. Regardless of sex, HFD caused down-regulation of lipogenic and inflammatory genes. Interestingly, females fed an HFD had up-regulated expression of apoptotic and cell repair–related genes compared with the males. This may suggest that females are more responsive to the acute hepatic injury effects caused by HFDs. In summary, neither male nor female rats displayed disrupted hepatic metabolic pathways after 72 hours of the HFD treatment. In addition, female rats appear to have protection from increases in fat deposition, possibly due to increased caloric expenditure; male rats fed an HFD were less active, as demonstrated by distance traveled in their home cage.     

肢体缺血预处理对婴幼儿心脏手术后心肌保护研究

目的探讨婴幼儿肢体缺血预处理（RIPC）的安全性及其对心脏的保护作用。方法以60例体重7Kg以下的室间隔缺损婴幼儿为研究对象,处理组（30例）手术前2次上肢RIPC,体外循环围手术期多个时间点监测乳酸脱氢酶（LDH）、肌酸激酶（CK）及其同工酶（CK—MB）、血清肌钙蛋白I（TnI）多个心肌酶学指标、冠脉丙二醛（MDA）、超氧化物歧化酶（soD）及心肌热休克蛋白（HSP70）含量,观察预处理后肢体疼痛及感觉障碍等。结果肢体RIPC后无疼痛、活动及感觉障碍等异常情况;处理组术前LDH、CK及TnI高于对照组,各酶学指标术后较对照组均有不同程度的降低,且部分时间点有统计学意义;处理组冠脉MDA低于对照组,SOD高于对照组;处理组心肌HSP70表达增高。结论婴幼儿肢体RIPC安全可行,并能减少心肌缺血再灌注后心肌酶的释放、氧自由基生成。上调HSP表达,对缺血再灌注心肌存在一定程度的保护作用。     

Tetrahydrocurcumin Upregulates the Adiponectin-AdipoR Pathway and Improves Insulin Signaling and Pancreatic β-Cell Function in High-Fat Diet/Streptozotocin-Induced Diabetic Obese Mice

Impairment of adiponectin production and function is closely associated with insulin resistance and type 2 diabetes, which are linked to obesity. Studies in animal models have documented the anti-diabetic effects of tetrahydrocurcumin (THC). Although several possible mechanisms have been proposed, the contribution of adiponectin signaling on THC-mediated antihyperglycemic effects remains unknown. Here, we report that adiposity, steatosis, and hyperglycemia were potently attenuated in high-fat diet/streptozotocin-induced diabetic obese mice after they received 20 and 100 mg/kg THC for 14 weeks. THC upregulated UCP-1 in adipose tissue and elevated adiponectin levels in the circulation. THC upregulated the AdipoR1/R2-APPL1-mediated pathway in the liver and skeletal muscle, which contributes to improved insulin signaling, glucose utilization, and lipid metabolism. Furthermore, THC treatment significantly (p < 0.05) preserved islet mass, reduced apoptosis, and restored defective insulin expression in the pancreatic β-cells of diabetic obese mice, which was accompanied by an elevation of AdipoR1 and APPL1. These results demonstrated a potential mechanism underlying the beneficial effects of THC against hyperglycemia via the adiponectin-AdipoR pathway, and thus, may lead to a novel therapeutic use for type 2 diabetes.