Effects of normobaric hyperoxia in a rat model of focal cerebral ischemia-reperfusion.

Recent studies suggest that normobaric hyperoxia can be beneficial, if administered during transient stroke. However, increased oxygenation theoretically may increase oxygen free-radical injury, particularly during reperfusion. In the present study, the authors assessed the benefit and risks of hyperoxia during focal cerebral ischemia and reperfusion. Rats were subjected to hyperoxia (Fio2 100%) or normoxia (Fio2 30%) during 2-hour filament occlusion and 1-hour reperfusion of the middle cerebral artery. At 24 hours, the hyperoxia group showed 70% (total) and 92% (cortical) reduction in infarct volumes as compared to the normoxia group. Levels of oxidative stress were evaluated using three indirect methods. First, since oxygen free radicals increase blood-brain barrier (BBB) damage, Evan's blue dye extravasation was quantified to assess BBB damage. Second, the expression of heme oxygenase-1 (HO-1), a heat shock protein inducible by oxidative stress, was assessed using Western blot techniques. Third, an immunoblot technique ("OxyBlot") was used to assess levels of protein carbonyl formation as a marker of oxidative stress-induced protein denaturation. At 24 hours, Evan's blue dye extravasation per average lesion volume was similar between groups. There were no significant differences in HO-1 induction and protein carbonyl formation between groups, in the ipsilateral or contralateral hemispheres, at 6 hours and at 24 hours. These results indicate that hyperoxia treatment during focal cerebral ischemia-reperfusion is neuroprotective, and does not increase oxidative stress.     

二烯丙基硫醚对大鼠脑缺血再灌注损伤后Nrf2、NQ01表达的影响

目的 探讨二烯丙基硫醚对大鼠局灶性脑缺血再灌注损伤后Nrf2、NQ01表达的影响.方法 实验动物随机分为假手术组、缺血再灌注组、200mg/kg二烯丙基硫醚预处理组.采用线栓法制备大鼠大脑中动脉缺血再灌注模型,缺血2h再灌注24h后进行神经行为学评分,测定脑梗死体积及脑组织中SOD、MDA活性,采用免疫荧光和Western Blot测定Nrf2、NQ01蛋白分子的表达.结果 与缺血再灌注组相比,大鼠经二烯丙基硫醚预处理后神经损害症状减轻,脑梗死体积缩小,SOD活性增强,同时MDA活性受到抑制,Nrf2、NQ01I蛋白分子表达上调.结论 二烯丙基硫醚对大鼠脑缺血再灌注损伤具有一定的神经保护作用,可能与其增强大鼠脑组织抗氧化酶活性和激活Nrf2/NQ01通路有关.     

Dietary omega-3 fatty acids and endothelium-dependent responses in porcine cerebral arteries.

PURPOSE: We sought to determine the effect of dietary omega-3 polyunsaturated fatty acids on cerebrovascular endothelium-dependent responses in studies performed on isolated porcine basilar arteries. METHODS: Male Yorkshire pigs (6-8 weeks old) were kept for 4 weeks on a standard diet (control group, n = 12) or on chow supplemented with polyunsaturated fatty acids (eicosapentaenoic acid, 3.5 g/day, or docosahexaenoic acid, 1.5 g/day; treated group, n = 12). Isometric tension recording of the basilar artery was carried out and responses were compared between the two groups. RESULTS: The regimen resulted in a decrease in the plasma arachidonic acid level and an increase in eicosapentaenoic acid. Endothelium-dependent relaxations induced by bradykinin and adenosine diphosphate were augmented in the basilar arteries of the treated group. Incubation with indomethacin (10(-5) M) prevented the augmentation of the relaxations induced by bradykinin, but not those caused by adenosine diphosphate. The indomethacin-sensitive, endothelium-dependent contractions to arachidonic acid remained comparable in the two groups, indicating that the activity of cyclooxygenase was not affected by the diet. CONCLUSIONS: Dietary supplementation with omega-3 polyunsaturated fatty acids enhances endothelium-dependent relaxations in the basilar artery by two mechanisms: 1) replacement of endogenous arachidonic acid and suppression of the concomitant release of vasoconstrictor prostaglandins from the endothelium, and 2) enhancement of the release of endothelium-derived relaxing factor.     

局灶性脑缺血再灌注损伤模型大鼠与促红细胞生成素的神经保护作用

背景：近年来动物实验和体外细胞培养研究证实促红细胞生成素对脑缺血具有神经保护作用,有关促红细胞生成素脑保护的作用机制目前尚未阐明。目的：通过观察缺血损伤区域脑组织细胞学形态,检测脑组织超氧化物歧化酶、丙二醛浓度,探讨促红细胞生成素对脑缺血再灌注损伤的保护作用。方法：采用线栓法建立Wistar大鼠局灶性缺血再灌注损伤模型,分别于缺血后2 h腹腔注射生理盐水3 000 U/kg、促红细胞生成素3 000,1 000 U/kg,并设假手术组。缺血再灌注损伤24 h后,应用苏木精-伊红染色法检测大鼠脑组织病理学变化,应用黄嘌呤氧化酶法和硫代巴比妥酸法分别测定超氧化物歧化酶活性和丙二醛浓度。结果与结论：形态学结果显示促红细胞生成素高剂量组较生理盐水组皮质神经细胞存活数量增多,损伤程度减轻;促红细胞生成素高、低剂量组超氧化物歧化酶活性均明显高于假手术组和生理盐水组(P < 0.05),丙二醛浓度明显低于假手术组和生理盐水组(P < 0.05);促红细胞生成素高剂量组超氧化物歧化酶活性明显高于促红细胞生成素低剂量组,丙二醛含量明显低于促红细胞生成素低剂量组(P < 0.05)。提示经腹腔注射促红细胞生成素,可使大鼠脑缺血再灌注损伤区神经细胞存活数量明显增加,可显著改善组织的病理学改变,其保护作用可能是通过促红细胞生成素清除自由基,拮抗过氧化损伤实现的。     

The effect of omega-3 fatty acids on aggression: A meta-analysis

Evidence suggests that omega-3 fatty acids are important for a variety of mental health outcomes and have been shown to improve both mood and behaviors. However, there is little consensus on whether omega-3 fatty acids are beneficial for reducing aggressive behaviors. The current study assesses the relationship between omega-3 fatty acids and aggression. A total of 73 effect sizes were calculated among 40 studies involving 7173 participants from both intervention and observational research designs. Effect sizes were separately meta-analyzed for two-group comparison studies (SMD = 0.20), pre-post contrast studies (ES_sg = 0.62), and associational studies (r = −0.06), in the fixed-effect model. Results from the random-effects model also suggest a range of effects of omega-3 fatty acids on reducing aggression (SMD = 0.24; ES_sg = 0.82; r = −0.09). Patterns in the relationship between omega–3s and aggression were additionally observed. Moderator analyses indicated that the effect of omega–3s on aggression is conditioned by how aggressive behaviors are measured, such as through self-report or parent/teacher surveys.     

三七三醇皂苷对大鼠脑缺血/再灌注脑损伤保护作用的实验研究

目的观察三七三醇皂苷（PTS）对大鼠脑缺血／再灌注损伤的脑保护作用，并初步探讨其作用机制。方法采用Longa改良的线栓法制备大脑中动脉阻塞（MACO）2h、再灌注6h、24h、72h的大鼠短暂局灶性脑缺血／再灌注模型，动物随机分假手术组、生理盐水对照组、三七三醇皂苷组。免疫组化法检测IL-1-β和ICAM-1。流式细胞仪检测细胞凋亡，同时利用TTC染色法测脑梗死体积。结果三七三醇皂苷组大鼠再灌注72h时脑梗死体积显著减小，6h、24h、72h各时间点IL-1β和ICAM-1阳性细胞数及凋亡细胞数亦明显减少。结论三七三醇皂苷可抑制脑缺血／再灌注后炎症因子分泌及细胞凋亡，从而起到脑保护作用。     

大鼠局灶脑缺血后AC133抗原表达的初探

目的探讨AC133抗原在脑缺血再灌注脑组织中是否表达.方法采用大鼠大脑中动脉缺血再灌注线栓法模型,将成年SD雄性大鼠随机分为(1)正常组,(2)假手术组,(3)动物模型组,分别取缺血再灌注2、3、4、7 d作为观察点,每个观察点6只大鼠,共36只大鼠,根据神经功能评分纳入实验,并采用免疫组化染色法检测脑组织AC133抗原表达.结果大脑缺血再灌注后4 d AC133蛋白在大脑半球梗死区周围的部分中、小血管内皮细胞胞浆染色阳性,而再灌注后2、3、7 d无阳性表达.结论大鼠脑缺血再灌注4 d脑梗死边缘区域部分血管内皮细胞AC133抗原表达阳性.AC133抗原可能参与大脑局灶缺血后的血管内皮功能.     

局灶性脑低温处理对大鼠创伤性脑损伤模型的保护作用

目的探讨局灶性低温处理对SD大鼠创伤性脑损伤（TBI）模型的保护作用并探讨其相关机制。 方法将15只雄性SD大鼠随机平均分成假手术组（sham）,非冷却组（non-cooling）和冷却组（cooling）。Non-cooling组和cooling组制作TBI模型,3组实验同步进行,创伤后低温处理3 h,复温3 h,过程中检测大鼠血气、皮层脑电。复温结束处死大鼠后,对脑组织进行TTC和HE染色以评价脑死亡和脑水肿情况,Western blot检测相关机制蛋白表达情况。 结果Sham组和non-cooling组受外部刺激脑组织代谢升高,cooling组较其他组脑组织代谢低,TTC和HE染色显示cooling组脑死亡的面积和细胞死亡数量均少于non-cooling组,差异均具有统计学意义（P<0.05）。大鼠TBI后局灶性低温处理能显著降低大脑皮层的癫痫样棘波,在回温时这种不完全抑制持续存在,且低温处理降低了GABA_B1R蛋白的表达,差异均具有统计学意义（P<0.05）。Cooling组的脑水肿情况较non-cooling组轻,且cooling组AQP4蛋白表达降低,差异均具有统计学意义（P<0.05）。 结论局灶性低温处理对TBI大鼠具有保护作用,能显著减轻TBI引起的脑水肿,抑制大脑皮层的癫痫样棘波,具体机制可能分别与GABA_B1R和AQP4相关。为临床治疗TBI提供了一种更加安全、简单有效的方法。     

Endogenous conversion of omega-6 into omega-3 fatty acids improves neuropathology in an animal model of Alzheimer's disease

Dietary supplementation with n-3 polyunsaturated fatty acids (n-3 PUFA) reduces amyloid-β (Aβ) and tau pathology and improves cognitive performance in animal models of Alzheimer's disease (AD). To exclude confounding variables associated with the diet, we crossed 3 × Tg-AD mice (modeling AD neuropathology) with transgenic Fat-1 mice that express the fat-1 gene encoding a PUFA desaturase, which endogenously produces n-3 PUFA from n-6 PUFA. The expression of fat-1 shifted the n-3:n-6 PUFA ratio upward in the brain (+11%, p < 0.001), including docosahexaenoic acid (DHA; +5%, p < 0.001) in 20 month-old mice. The expression of fat-1 decreased the levels of soluble Aβ?? (-41%, p < 0.01) at 20 months without reducing the level of insoluble forms of Aβ?? and Aβ?? in the brain of 3 × Tg-AD mice. The 3 × Tg-AD/Fat-1 mice exhibited lower cortical levels of both soluble (-25%, p < 0.05) and insoluble phosphorylated tau (-55%, p < 0.05) compared to 3 × Tg-AD mice, but only in 20 month-old animals. Whereas a decrease of calcium/calmodulin-dependent protein kinase II was observed in 3 × Tg-AD/Fat-1 mice (-039%, p < 0.05), altered tau phosphorylation could not be related to changes in glycogen synthase kinase 3β, cyclin-dependent kinase 5, or protein phosphatase type 2A enzymatic activity. In addition, the expression of the fat-1 transgene prevented the increase of glial fibrillary acidic protein (-37%, p < 0.01) observed in 20 month-old 3 × Tg-AD mice. In conclusion, the expression of fat-1 in 3 × Tg-AD mice increases brain DHA and induces biomarker changes that are consistent with a beneficial effect against an AD-like neuropathology.     

Therapeutic use of omega-3 fatty acids in bipolar disorder

Bipolar disorder (BD) is a severe, chronic affective disorder, associated with significant disability, morbidity and premature mortality. Omega-3 polyunsaturated fatty acids (PUFAs) play several important roles in brain development and functioning. Evidence from animal models of dietary omega-3 (n-3) PUFA deficiency suggest that these fatty acids are relevant to promote brain development and to regulate behavioral and neurochemical aspects related to mood disorders, such as stress responses, depression and aggression, as well as dopaminergic content and function. Preclinical and clinical evidence suggests roles for PUFAs in BD. n-3 PUFAs seem to be an effective adjunctive treatment for unipolar and bipolar depression, but further large-scale, well-controlled trials are needed to examine its clinical utility in BD. The use of n-3 as a mood stabilizer among BD patients is discussed here. This article summarizes the molecular pathways related to the role of n-3 as a neuroprotective and neurogenic agent, with a specific focus on BDNF. It is proposed that the n-3-BDNF association is involved in the pathophysiology of BD and represents a promising target for developing a novel class of rationally devised therapies.     

局灶性脑缺血再灌注致大鼠多器官功能障碍综合征模型的建立

目的建立大鼠局灶性脑缺血再灌注致多器官功能障碍综合征(MODS)模型，为探讨急性脑血管病(ACVD)致MODS的发病机制奠定基础。方法70只雄性WiStar大鼠随机分为正常对照组、假手术组及手术组(2h、12h、24h、48h、72h、5d6个时相点)，手术组又分为脑缺血0．5h再灌注组(I 0.5／R组)和脑缺血2h再灌注组(I2／R组)，采用线栓法制成大鼠大脑中动脉闭塞(MCAO)模型。观察并检测大鼠生命体征、血生化及主要器官病理形态学改变。依据全身炎症反应综合征(SIRS)和MODS的实验诊断标准判断SIRS和MODS的发生率。结果(1)I2／R组大鼠的体温升高，呼吸、心率增快，血生化各项指标明显增高，与正常对照组、假手术组及I 0.5／R组相比有显著性差异；(2)正常对照组各脏器组织细胞超微结构正常假手术组病理学改变轻微，随着脑缺血时间的处长，各脏器组织的病理改变亦随之加重；I 0.5／R组主要表现为功能障碍器官以炎症为主的非特异性改变；(3)I 0.5／R组SIRS的发生率为100％MODS的发生率为63．33％。结论(1)采用大脑中动脉线栓法可成功制作局灶性脑缺血再灌注致MODS模型。(2)脑缺血2h再灌注组100％发生SIRS，SIRS是ACVD致MODS的重要发病机制。     

Docosahexanoic acid and omega-3 fatty acids in depression.

Geographic areas where consumption of DHA is high are associated with decreased rates of depression. DHA deficiency states, such as alcoholism and the postpartum period, also are linked with depression. Individuals with major depression have marked depletions in omega-3 FAs (especially DHA) in erythrocyte phospholipids compared with controls. These data suggest that DHA may be associated with depression, and the limited data available on supplementation with DHA or other omega-3 FAs seem to support the hypothesis that DHA may have psychotropic effects. Overall, the use of EFAs is promising, particularly in view of the many illnesses potentially treatable with these substances; however, larger, carefully designed studies are needed to establish whether DHA is an effective and safe antidepressant, mood stabilizer, or antipsychotic. A few preliminary trials of DHA are in progress, but no studies comparing DHA against placebo or against an established antidepressant have been carried out. Studies to address this issue are being developed at the Massachusetts General Hospital. Studies likely will require escalating doses of DHA, eventually reaching high levels so as to ensure that patients will avoid a potentially ineffective subclinical dose. Careful monitoring of dietary intake among subjects also will necessary because a high intake of omega-3-rich foods may confound results. Finally, large-scale, placebo-controlled, double-blind trials comparing the efficacy and safety of DHA against standard antidepressants are required before psychiatrists can recommend DHA therapy as effective and safe for the treatment of depression and other mood disorders. Given the popularity of self-medication by patients who already are taking marketed antidepressants, studies examining the use of DHA as an augmentor to standard antidepressants may answer whether DHA can occupy a niche as an augmenting agent for patients who have made a partial response or have not responded to conventional antidepressants. Considering that natural medications generally seem best for treating mild to moderate illness, the role of DHA as a therapy for minor and subsyndromal depression also should be considered. It is hoped that studies of these types will help to clarify some of the knowledge gaps outlined in this article.     

通心络对大鼠脑缺血-再灌模型脑保护作用的研究

目的探讨通心络胶囊对脑缺血再灌注损伤的保护作用机制。方法用Zea Longa方法制作大鼠大脑中动脉缺血-再灌模型,观察不同剂量的通心络对缺血-再灌脑损伤大鼠脑组织形态学、脑脊液、行为学等的影响。结果通心络不同剂量均能降低脑缺血-再灌损伤大鼠神经功能评分,减轻脑水肿、缩小脑梗死面积、降低脑脊液中兴奋性氨基酸及乳酸含量。结论通心络对脑缺血再灌注损伤有保护作用。     

The protective effect of fish n-3 fatty acids on cerebral ischemia in rat prefrontal cortex

This study presents neuroprotective effects of fish n-3 EFA on the prefrontal cortex after cerebral ischemia and reperfusion. Eighteen rats divided into three groups. Group A rats were used as control. Cerebral ischemia and reperfusion was produced in rats either on a standard diet (Group B) or a standard diet plus fish n-3 EFA for 14 days (Group C). The malondialdehyde (MDA) levels and activities of superoxide dismutase (SOD) and catalase (CAT) were measured and the number of apoptotic neurons was counted. The levels of MDA and activities of SOD increased in Group B rats as compared to Group A rats, and decreased in Group C rats as compared to Group B rats. The activities of CAT increased in Group C as compared to Group B rats. The number of apoptotic neurons in the prefrontal cortex was lower in Group C as compared to Group B rats.     

毛蕊异黄酮对大鼠脑缺血再灌注损伤的保护作用

目的探讨毛蕊异黄酮对大鼠脑缺血再灌注损伤的保护作用及机制。方法采用大脑中动脉阻塞(MCAO)制备局灶性脑缺血模型,将SD大鼠随机分为MCAO组、溶剂对照组(vehicle组)以及毛蕊异黄酮处理组(calycosin组),缺血再灌注48 h后观察各组神经功能学评分和脑梗死容积大小。术前、术后6 h、24 h、48 h取脑组织样本,分别检测其超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、谷胱甘肽过氧化物酶(GSH-PX)、丙二醛(MDA)的变化。结果 calycosin组神经功能评分优于MCAO组和vehicle组(P<0.05);calycosin组脑梗死容积小于MCAO组和vehicle组(P<0.05);与MCAO组相比,calycosin组的脑组织SOD、CAT、GSH-PX活力升高,MDA的含量下降,差异均具有显著性(P<0.05)。结论毛蕊异黄酮对大鼠局灶性脑缺血再灌注损伤有一定的神经保护作用,其保护作用与毛蕊异黄酮能降低脑内氧自由基水平、控制脂质过氧化程度有关。     

Enhancing effect of dietary supplementation with omega-3 fatty acids on plasma fibrinolysis in normal subjects

A supplement of MaxEPA oil containing 5 g of omega-3 polyunsaturated fatty acids was given for two weeks to nine normal volunteers. The vascular plasminogen activator (VPA) level increased and there was a fall in the levels of inhibitors of vascular plasminogen activator (IPA) and of plasmin, alpha 2-antiplasmin (alpha 2-AP). No significant changes occur in serum cholesterol, triglycerides, HDL or LDL levels.