局灶性脑缺血再灌注损伤后大鼠血脑屏障通透性的研究

【目的】探讨局灶性缺血再灌注损伤后早期大鼠血脑屏障(blood brain barrier,BBB)功能障碍的变化和水肿形成的规律。【方法】应用伊文思蓝法(Evans-Blue,EB)观察再灌注后不同时间点BBB通透性变化,采用干湿重法计算脑含水量评估脑水肿、TTC法评估脑梗死面积。【结果】脑缺血再灌注3 h时,大鼠BBB通透性明显增加(P<0.05),24 h最高(P<0.01);缺血再灌注各组缺血侧大脑半球EB含量与对侧相比差异有显著性(P<0.05)。与假手术组相比EB含量差异均有显著性(P<0.05)。脑含水量变化与BBB通透性改变呈平行关系;但缺血再灌注后各时间点梗死面积差异无显著性。【结论】缺血再灌注损伤早期,大鼠BBB完整性受到破坏,脑水肿加重,因此应将BBB的结构和功能稳定性作为缺血再灌注损伤早期治疗的关注重点。     

牛初乳蛋白对大鼠股骨密度的影响研究

目的探讨牛初乳蛋白对去卵巢大鼠骨密度等指标的影响。方法将60只清洁级雌性SD大鼠随机分为假手术组、去卵巢对照组和喂食牛初乳蛋白的去卵巢低、中、高剂量共5组,其中3个剂量组每天分别给予牛初乳蛋白0.20、1.00和2.00g/kgbw连续灌胃12周。检测体重、股骨长度、股骨重量,股骨近心端、中段和远心端骨密度的变化。结果喂食牛初乳蛋白的各剂量组骨密度、股骨重/骨长、股骨重/体重均显著高于模型对照组。结论每天给予0.20mg/kgbw牛初乳蛋白能显著增加去势大鼠股骨近心端、中段和远心端的骨密度。     

Intake of hot water–extracted apple protects against myocardial injury by inhibiting apoptosis in an ischemia/reperfusion rat model

Intakes of apple and its products are shown to reduce the risk of coronary heart disease by delaying occlusion of coronary arteries. In our previous study, we showed that apple pectin protected against myocardial injury by prohibiting apoptotic cascades in a rat model of ischemia/reperfusion. Thus, we hypothesized that water-extracted apple, into which apple pectin was released from the cell wall, might exhibit the same efficacy as apple pectin. To test this hypothesis, we fed rats either cold water– (400 mg kg⁻¹ d⁻¹) or hot water–extracted apples (HWEA; 40, 100, and 400 mg kg⁻¹ d⁻¹). Three days later, the rats were subjected to myocardial injuries by ligating the left anterior descending coronary artery (30 minutes), and subsequently, the heart (3 hours) reperfused by releasing the ligation. Only the rats that were supplemented with HWEA (400 mg kg⁻¹ d⁻¹) showed significant reductions in infarct size, which was 28.5% smaller than that of the control group. This infarct size reduction could be partly attributed to the prevention of steps leading to apoptosis. These steps are manifested by a higher Bcl-2/Bax ratio, lower procaspase-3 conversion to caspase-3, and inhibition of DNA nick generation, which reflects the extent of apoptosis. The findings indicate that HWEA supplementation reduces myocardial injury by inhibiting apoptosis under ischemia/reperfusion conditions. In conclusion, this study suggests that apple intake, specifically boiled apple, might reduce the risk of coronary heart disease by inhibiting postocclusion steps, such as myocardial injury after artery occlusion, as well as preocclusion steps, such as atherosclerotic plaque formation.     

缬沙坦对大鼠心肌缺血再灌注损伤P-选择素的影响

目的通过结扎冠状动脉制作大鼠心肌缺血再灌注模型,观察血管紧张素Ⅱ-1型受体（AT1）拮抗剂缬沙坦（valsar-tan）对大鼠心肌缺血再灌注损伤（MIRI）P-选择素影响。并初步探讨其作用机制。方法90只Wister大鼠随机分为4组：l组：假手术组（10只）,2组：缺血组（20只）,3组：缺血再灌注组（30只）,4组：缬沙坦组（30只）。其中1,2,3组用生理盐水2ml每天灌胃,4组用缬沙坦20mg／kg每天灌胃。共灌胃4周制作模型。1组只穿线不结扎。2组分别结扎左冠状动脉前降支30和60min各10只。3组结扎冠状动脉前降支30min后分别再灌注60、120和360min各10只。4组结扎冠状动脉前降支30min后分别再灌注60、120和360min各10只。酶联免疫吸附法测定不同时间血清P-选择素浓度。观察缬沙坦对大鼠心肌缺血再灌注心肌的保护作用。结果在缬沙坦组及缺血再灌注组P-选择素逐渐升高（P〈0．05或P〈0．01）。缬沙坦组较缺血再灌注组P-选择素降低（P〈0．01）。缬沙坦可以减少P-选择素的释放。结论缬沙坦可以减轻MIRI,可能通过减少P-选择素的释放,减轻心肌细胞的损伤。     

白藜芦醇对心肌缺血再灌注损伤的保护作用及机制研究

目的研究白藜芦醇对大鼠心肌缺血再灌注损伤的保护作用,并进一步阐明其机制。方法建立心肌缺血再灌注损伤模型,持续观察标准Ⅱ导联心电图变化,测定乳酸脱氢酶(LDH),丙二醛(MDA)及超氧化物歧化酶(SOD)含量,确定心肌损伤程度。心肌细胞凋亡的检测采用逆转录聚合酶链反应检测bcl-2和bax mRNA的表达;Western blot检测bcl-2和bax蛋白表达。结果白藜芦醇能降低大鼠心肌冠脉结扎后ST段抬高,降低LDH和MDA水平,升高SOD水平,抑制bax而增强bcl-2的表达,减少心肌细胞凋亡。结论白藜芦醇对冠脉结扎诱发的大鼠心肌缺血再灌注损伤有保护作用,其机制可能与上调bcl-2蛋白表达,下调bax蛋白表达抑制心肌细胞凋亡有关。     

NO对器官缺血再灌注损伤保护作用研究进展(综述)

一氧化氮(NO)吸入疗法是90年代才逐渐发展起来的一种新技术。近年研究发现NO不仅可以治疗肺动脉高压而且对器官的缺血再灌注损伤均有一定的保护作用。其中,NO对肺脏的保护作用最显著,研究主要集中在吸入NO的剂量、时间、相关机制及影响因素方面。NO对心肌作用的相关研究越来越多。另外,NO对消化道、肾脏及其他器官的缺血再灌注损伤也有保护作用。但由于NO的应用时间较短,其相关机制尚不清楚。     

Neuroprotective effect of oral choline administration after global brain ischemia in rats

Abstract

Choline – now recognized as an essential nutrient – is the most common polar group found in the outer leaflet of the plasma membrane bilayer. Brain ischemia-reperfusion causes lipid peroxidation triggering multiple cell death pathways involving necrosis and apoptosis. Membrane breakdown is, therefore, a major pathophysiologic event in brain ischemia. The ability to achieve membrane repair is a critical step for survival of ischemic neurons following reperfusion injury. The availability of choline is a rate-limiting factor in phospholipid synthesis and, therefore, may be important for timely membrane repair and cell survival. This work aimed at verifying the effects of 7-day oral administration with different doses of choline on survival of CA1 hippocampal neurons following transient global forebrain ischemia in rats. The administration of 400 mg/kg/day divided into two daily doses for 7 consecutive days significantly improved CA1 pyramidal cell survival, indicating that the local availability of this essential nutrient may limit postischemic neuronal survival.     

实验性家兔缺血预适应对心肌缺血再灌注损伤的保护作用

目的采用家兔心肌缺血再灌注损伤动物模型，观察缺血预适应对心肌缺血再灌注损伤的心肌保护作用。方法将家兔随机分成3组，即假手术组、缺血再灌注组、缺血预适应组，观察血清心肌酶学变化及心肌细胞的超微结构。结果（1）缺血预适应组心肌酶水平与缺血再灌注组相比差异均极为显著（P〈0．01）；（2）缺血预适应可明显改善亚细胞结构损害。结论缺血预适应可以降低心肌酶活性，缩小梗死面积，改善亚细胞结构损害，对心肌缺血再灌注损伤有保护作用。     

硒对家兔心肌缺血再灌注损伤膜磷脂保护作用

目的观察硒对家兔心肌缺血再灌注损伤(IRI)膜磷脂的保护作用。方法 24只家兔,雌雄各半,随机分成假手术组、缺血再灌注组、硒组,分别检测心肌组织中总磷脂(PL)、总胆固醇(Ch)、磷脂酰乙醇胺(PE)、心磷脂(CL)含量。结果缺血再灌注组与假手术组比较,缺血再灌注组PL、PE、CL含量(41.21±9.71、415.30±31.25、200.56±29.41)明显降低(P<0.05),Ch含量(88.75±14.03)明显升高(P<0.05)。硒组与缺血再灌注组比较,硒组PL、PE、CL含量(58.73±11.12、764.34±51.87、325.79±31.14)明显升高(P<0.05),硒组Ch含量(62.41±12.11)明显降低(P<0.05)。结论硒对家兔心肌缺血再灌注损伤膜磷脂有保护作用。     

氟伐他汀预防兔心肌缺血再灌注损伤的实验研究

目的研究不同剂量氟伐他汀的短期预处理对兔心缺血再灌注损伤的保护作用及其机制。方法大耳白兔35只随机分为5组(n=7):⑴假手术对照组(Sham组),⑵缺血再灌注组(IR组),⑶氟伐他汀干预组(F组)分为氟伐他汀小剂量F1(2mg/kg)、中剂量F2(5 mg/kg)、大剂量F3(20 mg/kg)3组。实验中持续监测左室收缩压(LVSP)、左室舒张末压(LVEDP)、左室内收缩压最大上升速率和下降速率(±dp/dtm ax)的变化,再灌注结束后用伊文氏蓝和TTC染色法确定缺血和梗死心肌范围,进行心肌组织一氧化氮(NO)含量及一氧化氮合酶(NOS)活性的测定。结果F组中的F2组和F3组中心功能各项指标较IR组明显改善;心肌组织NO水平较IR组显著增高;心肌梗死面积较IR组明显减小,F1组无明显变化。结论适当剂量的氟伐他汀短期预处理对兔心肌缺血再灌注损伤有明显的保护作用,其机制之一可能与NO有关。     

天麻素对局灶脑缺血再灌注海马中BDNF及TrkB的影响

目的 探讨天麻素对局灶性脑缺血再灌注损伤的海马脑源性神经营养因子及其受体TrkB含量变化的影响.方法 120只SD大鼠体重200～2209,随机分为三组:假手术组(n=40),局灶脑缺血再灌注组(n=40)和天麻素治疗组(n=40).线栓法制备大脑中动脉梗阻(MCAO)模型,药物组在脑缺血再灌注即刻和12h腹腔注射天麻素,模型组和假手术组均注射等量生理盐水.分别在缺血再灌注2h、4h、6h、12h和24h处死动物,运用RT-PCR技术检测缺血侧海马组织内BDNF和TrkB的mRNA的表达变化.结果 再灌注损伤后,损伤侧海马组织内BDNF和TrkB的mRNA表达均增高.在天麻素治疗组中BDNF和TrkB的mRNA于再灌注2h上升,4h达高峰.结论 脑缺血后损伤侧海马神经元内BDNF和TrkB的mRNA含量增多,可能有利于受损神经元的修复.     

Tea polyphenols may attenuate the neurocognitive impairment caused by global cerebral ischemia/reperfusion injury via anti-apoptosis

Background/aims: Global cerebral ischemia/reperfusion (GCIR) may incur neurocognitive impairment. Tea polyphenols (TP) have strong anti-oxidant capacity. This study planned to investigate the protective effect of TP against the neurocognitive impairment caused by GCIR and its mechanism.

Methods: One-stage anterior approach for cerebral four-vessel occlusion (4VO) was used to construct the GCIR model. Sprague Dawley rats were randomly classified into Sham group, GCIR group, and TP group (n = 50 per group). Besides receiving the same 4VO, the rats in TP group were treated with TP (6.4%) injection from the tail vein 30 minutes before cerebral ischemia. Morris water-maze test was used to evaluate the changes in space recognition and memory and open field activity test to assess the activity and motor function of rats. The cell apoptotic study in hippocampal CA1 region at specified time points (12, 24, 48, and 72 hours after surgery) was carried out by the flow cytometry, histology (hematoxylin and eosin staining), and immunohistochemical (terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling staining) examinations. One-way analysis of variance and least significant difference t-test were used and statistical significance considered at P < 0.05.

Results: Compared with the GCIR group, the TP group was significantly attenuated in the impairment of space recognition and memory caused by GCIR and so was the neuronal apoptosis in the hippocampal CA1 region (P < 0.05).

Conclusion: TP may attenuate the impairment of space recognition and memory caused by GCIR via anti-apoptosis.     

肠道缺血再灌注损伤对血浆游离氨基酸水平的影响

目的研究肠道缺血再灌注损伤时肠道黏膜损伤和血浆游离氨基酸的变化。方法24只健康雄性SD大鼠随机分为3组（每组8只）：空白组、假手术组和肠道缺血再灌注（I/R）组。测定所有大鼠空肠和回肠黏膜的厚度和绒毛高度,进行下腔静脉取血,血浆沉淀蛋白质后测定游离氨基酸水平。结果I/R组与空白组和假手术组比较,空、回肠的黏膜厚度和绒毛高度明显下降［空肠黏膜厚度：(401.50±117.79)、(529.22±54.73)、(499.54±64.48)μm,F=31.869,P=0.000;空肠绒毛高度：(271.37±84.29)、(365.26±46.98)、(349.67±56.11)μm,F=30.472,P=0.000;回肠黏膜厚度：(254.20±43.56)、(324.70±30.56)、(298.26±58.46)μm,F=30.442,P=0.000;回肠绒毛高度：(169.37±37.25)、(221.62±37.26)、(193.25±38.39)μm,F=24.145,P=0.000］,假手术组和I/R组的血浆总游离氨基酸(F=5.075,P=0.016)、8种必需氨基酸(F=11.216,P=0.000)、谷氨酰胺(F=4.326,P=0.027)和支链氨基酸（BCAA）(F=10.662,P=0.001)较空白组降低,差异均有统计学意义（P均<0.05）,且I/R组的必需氨基酸和支链氨基酸水平明显低于假手术组（P均<0.05）。芳香族氨基酸在3组中的含量差异无统计学意义(F=0.578,P=0.570)。假手术组和I/R组的支链氨基酸/芳香族氨基酸比值显著低于空白组［(2.4±0.6)、(1.9±0.4)、(3.1±0.7),F=5.215,P=0.014］,I/R组低于假手术组,但差异无统计学意义（P>0.05）。假手术组和I/R组磷酸乙醇胺(F=5.897,P=0.009)、牛磺酸(F=10.702,P=0.001)、瓜氨酸(F=6.360,P=0.007)、胱氨酸(F=15.344,P=0.000)和磷酸丝氨酸(F=4.878,P=0.018)水平较空白组均有所降低,且I/R组的牛磺酸和胱氨酸与假手术组相比明显减少（P均<0.05）。I/R组血浆鸟氨酸(F=4.961,P=0.017)、精氨酸(F=13.940,P=0.000)浓度低于空白组和假手术组,差异均有统计学意义（P均<0.05）。I/R和假手术组色氨酸(F=5.429,P=0.031)和谷氨酸(F=15.241,P=0.000)浓度较空白组增高,且I/R组谷氨酸浓度明显高于假手术组（P<0.05）。结论大鼠肠道缺血再灌注损伤引起肠道黏膜损伤和血浆游离氨基酸变化,肠道屏障损伤可能与谷氨酰胺浓度下降、蛋白分解增加相关。     

Preoperative fasting induced protection against renal ischemia/reperfusion injury is independent of ghrelin in mice

One of the factors negatively influencing the outcome after kidney transplantation is ischemia-reperfusion (I/R) injury. Preoperative fasting is able to confer protection against I/R injury. We hypothesized that the protection imposed by preoperative fasting is mediated by increased levels of acylated ghrelin. Male C57BL/6 mice, 10 to 12 weeks old, were fasted for 1, 2, or 3 days, after which, acylated ghrelin levels were determined. Ad libitum fed mice were injected with acylated ghrelin or phosphate-buffered saline before renal I/R injury. Furthermore, mice were fasted for 3 days during which they were injected with a growth hormone secretagogue receptor antagonist, to block the effects of ghrelin, or a vehiculum. Bilateral renal I/R injury was induced by clamping the artery and vein of the left and right kidney simultaneously for 37 minutes. Kidney function was assessed by means of serum urea values determined at 24 and 48 hours after reperfusion. Fasting significantly increased acylated ghrelin serum levels. Ghrelin suppletion in ad libitum fed animals or ghrelin receptor blockade in fasted animals did not affect renal function after I/R injury. Our data suggest that the increased levels of acylated ghrelin induced by fasting do not mediate its protection against renal I/R injury.     

Anti-inflammatory and antioxidant effects of infliximab in a rat model of intestinal ischemia/reperfusion injury

The aim of this study was to investigate the possible protective effects of infliximab on oxidative stress, cell proliferation and apoptosis in the rat intestinal mucosa after ischemia/reperfusion (I/R). A total of 30 male Wistar albino rats were divided into three groups: sham, I/R and I/R+ infliximab; each group comprised 10 animals. Sham group animals underwent laparotomy without I/R injury. I/R groups after undergoing laparotomy, 1 hour of superior mesenteric artery ligation occurred, which was followed by 1 hour of reperfusion. In the infliximab group, 3 days before I/R, infliximab (3?mg/kg) was administered intravenously. All animals were killed at the end of reperfusion and intestinal tissues samples were obtained for biochemical and histopathological investigation in all groups. To date, no biochemical and histopathological changes have been reported regarding intestinal I/R injury in rats due to infliximab treatment. Infliximab treatment significantly decreased the elevated tissue malondialdehyde levels and increased reduced superoxide dismutase and glutathione peroxidase enzyme activities in intestinal tissues samples. I/R caused severe histopathological injury including mucosal erosions, inflammatory cell infiltration, necrosis, hemorrhage, and villous congestion. Infliximab treatment significantly attenuated the severity of intestinal I/R injury, inhibiting I/R-induced apoptosis, and cell proliferation. Because of its anti-inflammatory and antioxidant effects, infliximab pretreatment may have protective effects on the experimental intestinal I/R model of rats.     

川芎嗪预处理对沙鼠脑缺血再灌注损伤影响

目的 探讨川芎嗪预处理对沙鼠前脑缺血再灌注损伤的保护作用及机制。方法 雄性沙鼠随机分为对照、脑缺血再灌注、缺血预处理、川芎嗪预处理组,参照Kirino法制备脑缺血再灌注模型,Kitagawa法制备脑缺血预处理模型,HE染色法观察海马区神经细胞形态变化,免疫组织化学法检测神经胶质纤维酸性蛋白(GFAP)表达,原位缺口末端标记法(TUNEL)检测神经细胞凋亡情况,4-pellet taking test(4-PTT)旱路迷宫法测试动物学习记忆功能。结果 与脑缺血再灌注组比较,缺血预处理和川芎嗪预处理组中存活神经元密度(12.93±3.17,18.74±4.21)增加;GFAP(8.50±1.25,12.72±1.38)表达增加,凋亡神经细胞数量(16.50±5.25,9.72±3.38)下降;参照记忆指数和工作记忆指数得到改善(P均<0.05)。结论 川芎嗪预处理可改善脑缺血再灌注沙鼠的学习记忆功能,其机制与增强星形胶质细胞活性、减少神经细胞凋亡有关。     

Effects of creatine in a rat intestinal model of ischemia/reperfusion injury

Purpose  

Creatine belongs to a buffering system of cellular ATP level and has been reported to display direct antioxidant activity. Aim of this work was to investigate whether creatine treatment could ameliorate the antioxidant response of intestinal cells and limit the oxidative injury induced by anoxia and subsequent reoxygenation.     

多ADP-核糖聚合酶在大鼠心脏缺血／再灌注损伤中的作用

目的探讨多ADP-核糖聚合酶[Poly（ADP-ribose）polymerase,PARP]在大鼠心脏缺血／再灌注（ischemiaandreperfusion,I／R）损伤中的作用。方法将48只大鼠按随机数字法分为I／R组、I／R＋DPQ（PARP抑制剂）组、I／R＋DMSO（二甲基亚枫）组和对照组,建立大鼠心脏I／R模型,检测各组大鼠心肌中PARP的表达、心功能和心肌细胞凋亡的变化。结果在大鼠心脏I／R损伤中PARP表达增加,应用DPQ后,PARP表达显著减少（5．04±1．25VS2．334-0．65,t=1．35,P〈0．05）;抑制PARP的活性能使大鼠心脏左心室内压（LVDP）、室内压最大上升速率（＋dp／dt）和室内压最大下降速率（-dp／dt）显著增加,改善心脏功能。抑制PARP的活性能使大鼠心肌细胞凋亡率从（34±6．2）％显著降低至（23±3．8）％（t=2．25,P〈0．05）。结论在大鼠心脏I／R过程中,PARP的表达明显增加,并加重心脏损伤。应用药物抑制PARP的表达可以减少心脏损伤,具有心脏保护作用。