大黄素对骨髓间充质干细胞移植治疗缺血性再灌注肾损伤的影响

BACKGROUND: Studies have shown that emodin protects against intestinal ischemia-reperfusion injury by inhibiting the release of inflammatory factors.     

Priming of mesenchymal stem cells with oxytocin enhances the cardiac repair in ischemia/reperfusion injury

Oxytocin stimulates the cardiomyogenesis of embryonic stem cells and adult cardiac stem cells. We previously reported that oxytocin has a promigratory effect on umbilical cord blood-derived mesenchymal stem cells (UCB-MSCs). In this study, UCB-MSCs were cultured with oxytocin and examined for their therapeutic effect in an infarcted heart. UCB-MSCs were pretreated with 100 nM oxytocin and cardiac markers were assessed by immunofluorescence staining. Next, oxytocin-supplemented USC-MSCs (OT-USCs) were cocultured with hypoxia/reoxygenated neonatal rat cardiomyocytes and cardiac markers and dye transfer were then examined. For the in vivo study, ischemia/reperfusion was induced in rats, and phosphate-buffered saline (group 1), 1-day OT-USCs (group 2), or 7-day OT-USCs (group 3) were injected into the infarcted myocardium. Two weeks after injection, histological changes and cardiac function were examined. UCB-MSCs expressed connexin 43 (Cnx43), cardiac troponin I (cTnI), and α-sarcomeric actin (α-SA) after oxytocin supplementation and coculture with cardiomyocytes. Functional gap junction formation was greater in group 3 than in groups 1 and 2. Cardiac fibrosis and macrophage infiltration were lower in group 3 than in group 2. Restoration of Cnx43 expression was greater in group 3 than in group 2. Cnx43- and cTnI-positive OT-USCs in the peri-infarct zone were observed in group 2 and more frequently in group 3. The ejection fraction (EF) was increased in groups 2 and 3 in 2 weeks. The improved EF was sustained for 4 weeks only in group 3. Our findings suggest that the supplementation of UCB-MSCs with oxytocin can contribute to the cardiogenic potential for cardiac repair.     

Autacoid 14S,21R-dihydroxy-docosahexaenoic acid counteracts diabetic impairment of macrophage prohealing functions

Impaired macrophage functions imposed by diabetic complications and the suppressed formation of 14S,21R-dihydroxydocosa-4Z,7Z,10Z,12E,16Z,19Z-hexaenoic acid (14S,21R-diHDHA) in wounds contribute significantly to deficient wound healing in diabetics, but how are macrophage functions and 14S,21R-diHDHA formation associated? We studied 14S,21R-diHDHA generation from macrophages using liquid chromatography/mass spectrometry. The role in macrophage-mediated wound healing functions was determined using a murine splinted excisional wound healing model and in vitro assays. 14S,21R-diHDHA acts as a macrophage-generated autacoid, and its attenuated formation in macrophages of diabetic db/db mice was accompanied by impairment of macrophage prohealing functions. 14S,21R-diHDHA restored db/db macrophage-impaired prohealing functions by promoting wound re-epithelialization, formulation of granulation tissue, and vascularization. Additionally, 12/15-lipoxygenase-deficient macrophages, which are unable to produce 14S,21R-diHDHA, exhibited impaired prohealing functions, which also were restored by 14S,21R-diHDHA treatment. The molecular mechanism for 14S,21R-diHDHA-induced recovery of impaired prohealing functions of db/db macrophages involves enhancing their secretion of vascular endothelial growth factor and platelet-derived growth factor BB, decreasing hyperglycemia-induced generation of reactive oxygen species, and increasing IL-10 expression under inflammatory stimulation. Taken together, these results indicate that deficiency of 14S,21R-diHDHA formation by diabetic macrophages contributes to their impaired prohealing functions. Our findings provide mechanistic insights into wound healing in diabetics and suggest the possibility of using autologous macrophages/monocytes, treated with 14S,21R-diHDHA, or related compounds, to promote diabetes-impaired wound healing.Impaired wound healing associated with diabetes mellitus presents a major unresolved medical challenge. It is predicted that dysregulated cellular and molecular processes are responsible for impairments in wound healing in diabetes,¹ but the mechanisms underlying these processes require further elucidation. Macrophages play critical roles in wound healing: they engulf apoptotic polymorphonuclear leukocytes (PMNs), tissue debris, and infectious microorganisms; they promote wound healing, including accelerating re-epithelialization by promoting keratinocyte migration from the wound edge to decrease the epithelial gap and increasing the formation of granulation tissue by promoting fibroblasts and endothelial cells moving into wounds to cover the wound bed²; and they enhance angiogenesis, to repair damaged blood vessels and thus to supply sufficient oxygen and nutrients during healing.² Macrophage prohealing functions have been confirmed: macrophage transplantation into wounds promotes healing,^3,4 and macrophage depletion results in delayed wound healing.^5,6 The presence of diabetes, however, compromises macrophage functions and so contributes to disrupted wound healing.^1,4,7In addition to amino acid-based cytokines and growth factors, which are known to mediate wound healing and associated angiogenesis, lipid-derived molecules also may be important mediators. Docosahexaenoic acid (DHA), an essential ω-3 fatty acid, is a relatively abundant, endogenous lipid component in blood and in wounded full-thickness skin.⁸ Previous studies showed that DHA can ameliorate diabetes complications, such as cardiovascular disease, by improving endothelial function through anti-inflammatory mechanisms and reduced platelet aggregation, as well as by reducing blood triglyceride levels and increasing high-density lipoprotein cholesterol.^9–11 DHA can also significantly promote wound healing by enhancing angiogenesis.¹² Resolvins, neuroprotectins/protectins, and maresins are lipid mediators generated naturally from DHA during acute inflammation that have potent anti-inflammatory and protective functions.^13,14 Their discovery has opened a new avenue for unraveling the mechanisms behind the beneficial effects of DHA. The DHA-derived lipid mediator neuroprotectin D1 (NPD1; 10R,17S-dihydroxydocosa-4Z,7Z,11E,13E,15Z,19Z-hexaenoic acid) enhances corneal wound healing,¹⁵ and 14S,21R-dihydroxydocosa-4Z,7Z,10Z,12E,16Z,19Z-hexaenoic acid (14S,21R-diHDHA), a novel endogenous DHA-derived lipid mediator, is generated by macrophages and in wounded skin.^8,16 14S,21R-diHDHA is produced by sequential enzymatic actions of 14S-hydroperoxylation-specific leukocyte-12-lipoxygenase (L-12-LOX) and ω-1-hydroxylation-specific P450.⁸ When applied to wounds, 14S,21R-diHDHA potently promotes healing and angiogenesis in wounds.^8,16Diabetes and the accompanying hyperglycemia and oxidative stress damage DNA, proteins, and lipids in various tissues. These conditions cause cellular and enzymatic dysfunction during the formation of cytokines and eicosanoids associated with cell growth, angiogenesis, and/or inflammation,^4,7,17–19 all of which are at least in part responsible for impairment of macrophage functions in diabetes.^18,19 We have observed that 14S,21R-diHDHA formation was significantly halted in diabetic wounds, compared with nondiabetic wounds in mice, which suggests that diabetic complications dysregulate the generation of DHA-derived lipid mediators.¹⁶ In addition, supplementation of 14S,21R-diHDHA into diabetic wounds counteracts diabetes-associated impairment of wound healing,¹⁶ indicating that 14S,21R-diHDHA is an important prohealing lipid mediator. Also, decreased 14S,21R-diHDHA formation in diabetes may affect prohealing functions of cells that participate in wound healing.The findings presented here demonstrate that diabetes-impaired prohealing functions of db/db macrophages are associated with decreased formation of 14S,21R-diHDHA, and could be ameliorated by treating diabetic macrophages with 14S,21R-diHDHA.     

干细胞因子和粒细胞集落刺激因子动员自身骨髓干细胞治疗缺血再灌注肾损伤

背景：骨髓干细胞可分化为肾脏组织固有细胞、修复损伤肾组织。正常情况下,外周血干细胞数目较少,骨髓干细胞动员剂可提高外周血干细胞数目。 目的：观察动员自身骨髓干细胞对缺血再灌注损伤肾脏修复作用及对缺氧诱导因子1α系统的影响,分析骨髓干细胞修复损伤肾脏的机制。 方法：SD大鼠随机分为4组。对照组不作处置;模型组制备肾缺血再灌注模型;治疗组给予缺血再灌注模型大鼠皮下注射骨髓干细胞动员剂干细胞因子200 μg/(kg•d)及粒细胞集落刺激因子50 μg/(kg•d),治疗对照组给予正常大鼠皮下注射与治疗组相同的药物,连续5 d。于术后5,10,17,24,31 d观察大鼠肾脏病理改变、骨髓干细胞表面抗原标记CD34⁺细胞表达以及缺氧诱导因子1α、血管内皮生长因子、血红素加氧酶1的表达变化。 结果与结论：①联合应用骨髓干细胞动员剂能明显增加损伤肾组织骨髓干细胞的数量,减轻肾组织损伤程度。②骨髓干细胞能促进肾组织缺氧诱导因子1α系统的表达,缺氧诱导因子1α系统及其靶基因产物血管内皮生长因子、血红素加氧酶1表达增加是骨髓干细胞促进急性肾损伤修复的可能机制之一。③骨髓干细胞动员剂对缺氧诱导因子1α系统的表达有一定的增强作用。     

骨髓间充质干细胞治疗肾缺血再灌注损伤的旁分泌机制

背景：骨髓间充质干细胞已用于肾缺血再灌注损伤修复的实验动物研究。 目的：探讨骨髓间充质干细胞治疗肾缺血再灌注损伤的旁分泌机制。 方法：体外培养、纯化并体外DAPI标记大鼠骨髓间充质干细胞,经下腔静脉移植入肾缺血再灌注损伤模型大鼠体内,观察骨髓间充质干细胞对肾缺血再灌注损伤肾功能的保护作用以及在受体鼠体内的迁移情况,并应用免疫组织化学法检测骨髓间充质干细胞治疗后第2天缺血肾脏组织中血管内皮生长因子、肿瘤坏死因子α细胞因子的表达。 结果与结论：与注射生理盐水的对照组比较,细胞移植组大鼠血清肌酐和尿素氮水平在移植后第1、2天明显降低(P < 0.05),但细胞移植组移植后第1、2天肾组织中均未见DAPI阳性细胞;第3、4天则逐渐可见DAPI阳性细胞。免疫组织化学染色结果显示,与对照组相比,移植后第2天肾组织中可见较多血管内皮生长因子阳性细胞,而肾组织中肿瘤坏死因子α阳性细胞明显减少。结果显示旁分泌机制参与了骨髓间充质干细胞治疗肾缺血再灌注损伤。     

Inhibition of myocardial ischemia/reperfusion injury by exosomes secreted from mesenchymal stem cells

Exosomes secreted by mesenchymal stem cells have shown great therapeutic potential in regenerative medicine. In this study,we performed meta-analysis to assess the clinical effectiveness of using exosomes in ischemia / reperfusion injury based on the reports published between January 2000 and September 2015 and indexed in the Pub Med and Web of Science databases. The effect of exosomes on heart function was evaluated according to the following parameters: the area at risk as a percentage of the left ventricle,infarct size as a percentage of the area at risk,infarct size as a percentage of the left ventricle,left ventricular ejection fraction,left ventricular fraction shortening,end-diastolic volume,and end-systolic volume. Our analysis indicated that the currently available evidence confirmed the therapeutic potential of mesenchymal stem cell-secreted exosomes in the improvement of heart function. However,further mechanistic studies,therapeutic safety and clinical trials are required for optimization and validation of this approach to cardiac regeneration after ischemia / reperfusion injury.     

基于动物实验系统评价干细胞治疗肾脏缺血再灌注损伤的可行性

文题释义：干细胞：是一类具有自我复制能力的多潜能细胞,可来源于骨髓、脐带、脂肪组织等;在一定条件下,它可以分化成多种功能细胞。根据干细胞所处的发育阶段分为胚胎干细胞和成体干细胞。根据干细胞的发育潜能分为3类：全能干细胞、多能干细胞和单能干细胞。系统评价：运用减少偏倚的策略,严格评价和综合针对某一具体问题的所有相关研究。Meta分析可能但不一定是这个过程的一部分。系统评价制作过程严谨、科学,具有良好的重复性,可为某一领域和专业提供大量新信息和新知识,在循证医学证据分级体系中被认为是临床研究证据中最高级别的证据。  摘要背景：随着干细胞研究的不断深入和对肾脏缺血再灌注损伤机制的逐渐明晰,干细胞治疗肾脏缺血再灌注损伤已在动物实验中广泛开展并取得了较大进展。因此,有必要开展系统评价以探究干细胞治疗肾脏缺血再灌注损伤的具体疗效。 目的：基于动物实验系统评估干细胞对缺血再灌注损伤肾功能、结构和机体免疫功能的影响及其向临床转化的可行性。 方法：计算机检索PubMed、Web of science、Embase、CNKI、维普和万方数据库,检索时间截止2019年5月。由2名研究者独立筛选文献、提取资料,采用SYRCLE动物实验偏倚风险评估工具评价纳入研究的方法学质量,并根据CERQual工具对证据质量进行评估。结果与结论：最终纳入17篇动物实验,但各研究间存在较大的临床异质性,故进行定性描述。相比于安慰剂组,干细胞治疗组动物的肾功能(血清肌酐和血尿素氮水平)均有改善,机体的免疫状况及肾脏的组织损伤也有所好转,但6个结局指标的证据质量均为“低”,同时纳入研究存在一定的偏倚风险。由于纳入研究存在实验设计、证据质量等方面的问题,尚不能确定干细胞的确切疗效以及是否能够或有必要开展进一步临床研究。因此,在开展临床试验之前,有必要进行高质量的临床前研究进一步评估干细胞治疗肾脏缺血再灌注损伤的疗效及向临床转化的可行性,以降低其向临床转化时的风险。ORCID: 0000-0002-3496-097X(尚志忠) 中国组织工程研究杂志出版内容重点：干细胞;骨髓干细胞;造血干细胞;脂肪干细胞;肿瘤干细胞;胚胎干细胞;脐带脐血干细胞;干细胞诱导;干细胞分化;组织工程     

肾缺血再灌注模型细胞凋亡与吡咯烷二硫代氨基甲酸的干预

背景：肾缺血/再灌注诱导产生大量活性氧,导致核因子κB的活化。激活的核因子κB通过调节诱导型一氧化氮合酶的生成,进而导致一氧化氮的大量产生和触发细胞凋亡。 目的：观察吡咯烷二硫代氨基甲酸对肾缺血再灌注后肾脏组织中核因子κB、诱导型一氧化氮合酶、一氧化氮、caspase-3和细胞凋亡指数的作用。 方法：将健康雄性Wistar大鼠随机分为3组：缺血再灌注组和吡咯烷二硫代氨基甲酸组通过右侧肾切除+左肾动脉夹闭 45 min建立肾缺血/再灌注模型,吡咯烷二硫代氨基甲酸组于实验前30 min尾静脉注射吡咯烷二硫代氨基甲酸 (100 mg/kg)。假手术组不给予缺血再灌注处理。 结果与结论：与假手术组相比,缺血再灌注组大鼠再灌注后肾组织核因子κB表达水平、血肌酐水平、尿素氮水平、诱导型一氧化氮合酶活性、一氧化氮表达水平、caspase-3表达水平和细胞凋亡水平增加(P < 0.05);而与缺血再灌注组相比,吡咯烷二硫代氨基甲酸组大鼠再灌注后以上指标均好转。说明肾缺血/再灌注损伤可引起肾组织结构损伤和细胞凋亡,且与核因子κB引起的一氧化氮高表达有关;应用核因子κB抑制剂吡咯烷二硫代氨基甲酸可对缺血再灌注肾损伤发挥明显的保护作用。     

Independent pathways of P-selectin and complement-mediated renal ischemia/reperfusion injury

Evidence from in vitro studies indicates that complement activation regulates the expression of P-selectin on endothelial cells. This suggests that in disorders such as ischemia/reperfusion injury, in which both complement and P-selectin have been shown to play a role, complement activation is a primary event and the effects of P-selectin are secondary. To test this hypothesis in vivo, we examined a mouse kidney model of ischemia/reperfusion injury. Surprisingly, the time course and extent of expression of P-selectin was unaltered in C3-deficient mice compared with wild-type mice, in which there was rapid but transient up-regulation of P-selectin on capillary walls and slower accumulation of complement split product on the tubular epithelium. In addition, treatment with anti-P-selectin antibody to reduce the neutrophil-mediated reperfusion damage was equally effective in the absence of C3. These data imply that complement and P-selectin-mediated pathways of renal reperfusion injury are mutually independent, a conclusion that is possibly explained by the differences in the location and time kinetics of complement activation and P-selectin expression. We conclude that in vivo interaction between complement and P-selectin is limited because of time and spatial considerations. Consequently, complement and P-selectin pose distinct targets for therapy.     

山莨菪碱预处置对大鼠肾脏缺血/再灌注损伤的影响

目的：观察山莨菪碱（654－2）对大鼠肾脏缺血－再灌注（I／R）损伤的影响及与IL－6和TNF－α的关系。方法：采用大鼠肾脏I／R损伤＋654－2预处置模型，分别观测再灌注不同时期SUN、Scr、肾系数变化及IL－6和TNF－α的含量。结果：用654－2预处理后再灌注4h（R4h）组的SUN、Scr和肾系数均高于未处置组（P＜0．01或P＜0．05），再灌注24h(R24h）组的Scr低于其对照组；654－2同时使R4h组血液和肾组织中的IL－6含量也高于其对照组（P＜0．01），使R24h组肾组织中IL－6高于其对照组。结论：654－2预处理加重早期肾I／R损伤，这种作用可能与IL－6增加有关；再灌注24h后才显示其治疗作用。     

他克莫司对大鼠肾缺血再灌注损伤的影响及其机制的研究

目的: 探讨他克莫司对大鼠肾缺血再灌注(I/R)损伤的保护作用及机制。方法: 将60只健康雄性Wistar大鼠随机分为3组:假手术组、I/R组和他克莫司处理组,每组各4个时点( 0.5 h、2 h、6 h、24 h)。建立肾I/R损伤模型;检测各组大鼠血清肌酐(Cr)、肿瘤坏死因子(TNF-α)、丙二醛(MDA)含量及超氧化物歧化酶(SOD)活性;用光学显微镜观察各组大鼠肾组织病理变化;用免疫组化法检测Fas和caspase-3蛋白的表达。结果: 在相应再灌注各时点,他克莫司处理组血清Cr、TNF-α和MDA水平均低于I/R组(P<0.05),而他克莫司处理组血清SOD活性高于I/R组(P<0.05)。他克莫司处理组肾组织损伤程度明显轻于I/R组。与假手术组比较,I/R组凋亡蛋白Fas和caspase-3表达水平显著增加(P<0.05),而他克莫司处理组凋亡蛋白Fas和caspase-3表达水平则低于I/R组(P<0.05)。结论: 他克莫司能有效抑制I/R引起的自由基产生、肾小管上皮细胞凋亡以及TNF-α水平降低,表明他克莫司对大鼠肾I/R损伤具有保护作用。     

〗雌激素调节Th17/Treg细胞免疫平衡抑制肾脏缺血再灌注损伤

目的：探讨雌激素（Estrogen,E2）对肾脏缺血再灌注损伤的作用及机制。方法：24只雌性SD大鼠随机分为4组：对照组（Control group）、去卵巢组（OVX group）、去卵巢后缺血再灌注损伤组（OVX+IRI group）和雌激素干预组（OE+IRI group）。各组大鼠分别于再灌注后6 h收集血液标本和肾脏组织标本,运用全自动生化分析仪检测肾功能;采用苏木素-伊红（HE）染色和Paller评分量化肾脏损害程度;应用流式细胞和ELISA技术检测外周血中CD3+CD4+T淋巴细胞的阳性表达率及细胞因子IL-17、IL-10的血清学水平。结果：在肾脏IRI早期,大鼠血尿素氮（BUN）、血肌酐（SCr）水平和肾脏组织损害程度均高于OVX组（P<0.01）,而经E2补充治疗后上述指标明显降低（P<0.05）;与OVX组比较,OVX+IRI组中CD3+CD4+T细胞阳性表达率和Th17细胞分泌的IL-17的浓度均明显升高（P<0.01）,Tregs分泌的IL-10的浓度减少（P<0.05）;而在OE+IRI组中,CD3+CD4+T细胞阳性表达率和IL-17的浓度降低（P<0.01）,IL-10的浓度升高（P<0.05）;此外,相关性分析显示细胞因子IL-17与BUN、SCr和肾脏Paller评分呈正相关性,而细胞因子IL-10与上述指标呈负相关性。结论：Th17/Treg的平衡破坏可能是肾脏IRI早期炎症反应的主要致病因素;E2可减轻肾脏IRI,其机制可能是通过调节Th17/Treg的平衡从而抑制由IRI诱发的炎症反应。     

An Angiotensin-converting enzyme inhibitor, zofenopril, prevents renal ischemia/reperfusion injury in rats

Zofenopril ameliorates experimental cardiac ischemia/reperfusion (IR) injury in animal models and exhibits beneficial cardiovascular effects in patients with myocardial infarction. The objective of the present research was to investigate whether zofenopril can protect against renal IR injury. Rats were divided into 4 experimental groups: (a) control, (b) IR (60 min of ischemia followed by 24 hr of reperfusion), (c) zofenopril (15 mg/kg/day for 2 days), and (d) zofenopril+IR. All of the rats underwent right nephrectomy, and the rats in the IR and zofenopril+IR groups also underwent IR.then the left kidneys were removed for biochemical analyses and microscopic examination. There were no abnormalities in the biochemical and microscopic findings in the preoperative right kidneys. The lipid peroxidation, protein oxidation, and nitric oxide levels as well as xanthine oxidase and myeloperoxidase activities were increased and the catalase and superoxide dismutase activities were decreased in the IR group; zofenopril treatment prevented these changes (p <0.05). In the IR group, the kidney sections showed severe acute tubular damage including brush border loss, nuclear condensation, cytoplasmic swelling, and loss of nuclei; in the zofenopril+IR group, the normal glomerular morphology was preserved and there was slight edema of the tubular cells. The renal damage score was significantly reduced in the zofenopril+IR group vs the IR group (p <0.05).In conclusion, IR injury caused oxidative damage in renal tissue and zofenopril prevented this IR injury.     

异丙酚和氯胺酮减轻大鼠肾缺血再灌注损伤

目的:观察异丙酚(propofol)或氯胺酮(ketamine)对缺血再灌注肾损伤(IR)大鼠肾组织病理变化的影响。方法:48只成年Wistar大鼠随机均分成6组,每组8只,分别为假手术组(S组)、缺血再灌注模型组(R组)、小剂量异丙酚(5mg/kg)组(P1组)、大剂量异丙酚(10mg/kg)组(P2组)、小剂量氯胺酮(10mg/kg)组(K1组)、大剂量氯胺酮(20mg/kg)组(K2组)。输液后72h处死所有大鼠,在实验开始及处死大鼠前取4mL静脉血放入低温冰箱中保存待测。处死大鼠后取部分肾脏组织置于甲醛及戊二醛溶液,用于石蜡切片,光镜及电镜观察肾脏组织结构的变化。另取一部分肾组织制作成肾组织匀浆待测。待测指标包括血肌酐(Scr)、血尿素氮(BUN)、丙二醛(MDA)、超氧化物歧化酶(SOD)。结果:与缺血再灌注模型组相比,异丙酚和氯胺酮能显著降低缺血再灌注肾损伤大鼠肾组织中MDA含量(P0.05),增强SOD活性(P0.05),使缺血再灌注肾损伤大鼠肾功能及组织学改变得到明显改善。结论:异丙酚或氯胺酮对肾缺血再灌注损伤有明显拮抗作用,其作用机制可能与药物抗氧化及抗炎作用有关。     

α-亚麻酸减轻糖尿病大鼠心肌缺血/再灌注损伤

 目的 研究摄食?-亚麻酸（ALA）对糖尿病大鼠心肌缺血/再灌注（MI/R）损伤的影响。方法 构建高脂饲料-链脲霉素诱导的2型糖尿病大鼠模型（HFD-STZ）,每日灌胃给予正常或HFD-STZ大鼠ALA处理（500 μg/kg）,4周后行心肌缺血（30 min）/再灌注（4或6 h）,并检测心肌梗死范围、血清肌酸激酶（CK）、乳酸脱氢酶（LDH）活性、细胞凋亡,用Western blot检测PI3K、Akt等。结果 HFD-STZ大鼠MI/R损伤加重,虽摄食ALA 4周对正常动物MI/R损伤无影响,但可将HFD-STZ大鼠的心梗面积减小至37.7% ± 5.4%,显著低于对照组的45.6% ± 8.5%（P < 0.05）,且血清CK、LDH活性及细胞凋亡减少;还可增加HFD-STZ大鼠心肌PI3K表达及Akt磷酸化。结论 长期摄食ALA有效减轻糖尿病大鼠MI/R损伤,可能与激活PI3K-Akt信号有关。     

Annexin 1 mimetic peptide protects against renal ischemia/reperfusion injury in rats

Inflammation is currently recognized as a key mechanism in the pathogenesis of renal ischemia–reperfusion (I/R) injury. The importance of infiltrating neutrophil, lymphocytes, and macrophage in this kind of injury has been assessed with conflicting results. Annexin 1 is a protein with potent neutrophil anti-migratory activity. In order to evaluate the effects of annexin A1 on renal I/R injury, uninephrectomized rats received annexin A1 mimetic peptide Ac2-26 (100 μg) or vehicle before 30 min of renal artery clamping and were compared to sham surgery animals. Annexin A1 mimetic peptide granted a remarkable protection against I/R injury, preventing glomerular filtration rate and urinary osmolality decreases and acute tubular necrosis development. Annexin A1 infusion aborted neutrophil extravasation and attenuated macrophage infiltration but did not prevent tissue lymphocyte traffic. I/R increased annexin A1 expression (assessed by transmission electron microscopy) in renal epithelial cells, which was attenuated by exogenous annexin A1 infusion. Additionally, annexin A1 reduced I/R injury in isolated proximal tubules suspension. Annexin A1 protein afforded striking functional and structural protection against renal I/R. These results point to an important role of annexin A1 in the epithelial cells defense against I/R injury and indicate that neutrophils are key mediators for the development of tissue injury after renal I/R. If these results were confirmed in clinical studies, annexin A1 might emerge as an important tool to protect against I/R injury in renal transplantation and in vascular surgery.     

BALB/c小鼠肾缺血再灌注损伤模型的建立与评价

背景：对于一些药物研究,小鼠是理想的造模工具,但由于小鼠耐受性相对较差,肾脏及肾蒂小且难于寻找,容易增加实验误差,导致造模失败。 目的：探讨BALB/c小鼠肾缺血再灌注损伤模型的建立方法,评价肾脏缺血时间对肾缺血再灌注损伤的影响。 方法：采用微型动脉夹夹闭小鼠双侧肾蒂的方法建立雄性BALB/c小鼠肾缺血再灌注损伤模型,根据肾缺血时间不同分为    0 min组(对照组)、30 min组、35 min组、45 min组,肾再灌注后24 h观察肾功能和肾脏病理组织学的变化,比较不同的肾脏缺血时间对上述指标的影响;观察45 min组小鼠肾缺血再灌注损伤后的生存率。 结果与结论：模型成功率95.9%,与对照组相比,肾缺血30 min组、35 min组和45 min组再灌注后24 h血清肌酐、尿素氮和肾脏病理组织学评分均升高,肾缺血45 min组生存率明显下降,差异均有显著性意义(P < 0.05)。结果提示,应用微型动脉夹夹闭小鼠双侧肾蒂的方法可制备稳定肾缺血再灌注损伤模型,雄性小鼠肾缺血35~45 min是造模较为理想的肾缺血时间,所得模型效果满意。     

3D-confocal structural analysis of bone marrow-derived renal tubular cells during renal ischemia/reperfusion injury

Bone marrow cells (BMC) have been shown to migrate into injured sites for parenchymal repair. However, the extent of BMC involvement is controversial. To determine whether and to what extent BMC contribute to renal parenchymal repair, we employed three-dimensional (3D) fluorescent confocal microscopy/video in renal warm and cold ischemia/reperfusion (I/R) injury using enhanced green fluorescent protein transgenic rats and their radiation chimeras. After induction of renal warm I/R injury in chimeras, BM-derived renal tubular cells were found in 2D microscopy as isolated single cells or clusters of 2-3 cells. Likewise, cold I/R injury resulted in host-derived tubular cells with frequencies approximately 0.2%. However, stringent confocal microscopic analysis and 3D image construction revealed that BM-derived tubules identified in 2D images were frequently artifacts of overlapping cells separately stained with different markers. The actual frequency in 3D analysis was approximately one-fourth of that seen in 2D analysis. 3D confocal imaging precisely detected BM-derived tubular epithelial cells and could be useful to study BMC contribution to tissue repair.     

Focal adhesion kinase signaling mediates acute renal injury induced by ischemia/reperfusion

Renal ischemia/reperfusion (I/R) injury is associated with cell matrix and focal adhesion remodeling. Focal adhesion kinase (FAK) is a nonreceptor protein tyrosine kinase that localizes at focal adhesions and regulates their turnover. Here, we investigated the role of FAK in renal I/R injury, using a novel conditional proximal tubule-specific fak-deletion mouse model. Tamoxifen treatment of FAK(loxP/loxP)//γGT-Cre-ER(T2) mice caused renal-specific fak recombination (FAK(ΔloxP/ΔloxP)) and reduction of FAK expression in proximal tubules. In FAK(ΔloxP/ΔloxP) mice compared with FAK(loxP/loxP) controls, unilateral renal ischemia followed by reperfusion resulted in less tubular damage with reduced tubular cell proliferation and lower expression of kidney injury molecule-1, which was independent from the postischemic inflammatory response. Oxidative stress is involved in the pathophysiology of I/R injury. Primary cultured mouse renal cells were used to study the role of FAK deficiency for oxidative stress in vitro. The conditional fak deletion did not affect cell survival after hydrogen peroxide-induced cellular stress, whereas it impaired the recovery of focal adhesions that were disrupted by hydrogen peroxide. This was associated with reduced c-Jun N-terminal kinase-dependent phosphorylation of paxillin at serine 178 in FAK-deficient cells, which is required for focal adhesion turnover. Our findings support a role for FAK as a novel factor in the initiation of c-Jun N-terminal kinase-mediated cellular stress response during renal I/R injury and suggest FAK as a target in renal injury protection.     

缺血再灌流损伤对肾毛细血管内皮细胞的影响──细胞化学观察

应用常规电镜及过氧化氢细胞化学技术，观察了缺血再灌流对鼠肾毛细血管内皮细胞的损伤情况。缺血６０ｍｉｎ，可致毛细血管内皮细胞明显肿胀，过氧化氢细胞化学表现为在内皮细胞表面有少量电子致密物沉积。缺血６０ｍｉｎ复流１０ｍｉｎ，毛细血管内皮细胞表面有大量电子致密物沉积。缺血６０ｍｉｎ复流３０ｍｉｎ及６０ｍｉｎ，内皮细胞损伤加重，毛细血管内皮细胞与基底层之间裂开、翻起，甚至剥脱。毛细血管内皮细胞与肾小管上皮细胞之间有电子致密物沉积，甚至肾小管上皮细胞基底部也有致密物沉积。