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1.
Ischemia/reperfusion (I/R) is at the basis of renal transplantation and acute kidney injury. Molecular mechanisms underlying proximal tubule response to I/R will allow the identification of new therapeutic targets for both clinical settings. microRNAs have emerged as crucial and tight regulators of the cellular response to insults including hypoxia. Here, we have identified several miRNAs involved in the response of the proximal tubule cell to I/R. Microarrays and RT-PCR analysis of proximal tubule cells submitted to I/R mimicking conditions in vitro demonstrated that miR-127 is induced during ischemia and also during reperfusion. miR-127 is also modulated in a rat model of renal I/R. Interference approaches demonstrated that ischemic induction of miR-127 is mediated by Hypoxia Inducible Factor-1alpha (HIF-1α) stabilization. Moreover, miR-127 is involved in cell-matrix and cell-cell adhesion maintenance, since overexpression of miR-127 maintains focal adhesion complex assembly and the integrity of tight junctions. miR-127 also regulates intracellular trafficking since miR-127 interference promotes dextran-FITC uptake. In fact, we have identified the Kinesin Family Member 3B (KIF3B), involved in cell trafficking, as a target of miR-127 in rat proximal tubule cells. In summary, we have described a novel role of miR-127 in cell adhesion and its regulation by HIF-1α. We also identified for the first time KIF3B as a miR-127 target. Both, miR-127 and KIF3B appear as key mediators of proximal epithelial tubule cell response to I/R with potential al application in renal ischemic damage management.  相似文献   

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目的:探讨缺血后处理对高胆固醇血症基础上发生的心肌缺血/再灌注损伤的影响及其可能的机制。方法:建立食源性高胆固醇血症大鼠模型,运用TTC染色、酶活性检测等方法测定缺血/再灌注所致的心肌损伤,用实时定量RT-PCR方法检测心肌组织中低氧诱导因子-1α(HIF-1α)mRNA水平,用Western blot方法检测HIF-1α蛋白水平。结果:高胆固醇血症加重了缺血/再灌注造成的心肌损伤,而缺血后处理显著缩小了高胆固醇血症大鼠缺血/再灌注所致的心梗面积,降低了血清肌酸激酶(CK)的活性,减少了心肌细胞凋亡。同时,缺血后处理提高了高胆固醇血症大鼠缺血心肌组织中HIF-1α的蛋白水平。结论:缺血后处理可以降低高胆固醇血症大鼠心肌对缺血/再灌注损伤的敏感性,其效应与心肌组织中HIF-1α的蛋白水平存在着相关性。  相似文献   

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Gut injury and loss of normal intestinal barrier function are key elements in the paradigm of gut-origin systemic inflammatory response syndrome, acute lung injury, and multiple organ dysfunction syndrome (MODS). As hypoxia-inducible factor (HIF-1) is a critical determinant of the physiological and pathophysiological response to hypoxia and ischemia, we asked whether HIF-1 plays a proximal role in the induction of gut injury and subsequent lung injury. Using partially HIF-1α-deficient mice in an isolated superior mesenteric artery occlusion (SMAO) intestinal ischemia reperfusion (I/R) injury model (45 min SMAO followed by 3 h of reperfusion), we showed a direct relationship between HIF-1 activation and intestinal I/R injury. Specifically, partial HIF-1α deficiency attenuated SMAO-induced increases in intestinal permeability, lipid peroxidation, mucosal caspase-3 activity, and IL-1β mRNA levels. Furthermore, partial HIF-1α deficiency prevented the induction of ileal mucosal inducible nitric oxide synthase (iNOS) protein levels after SMAO and iNOS deficiency ameliorated SMAO-induced villus injury. Resistance to SMAO-induced gut injury was also associated with resistance to lung injury, as reflected by decreased levels of myeloperoxidase, IL-6 and IL-10 in the lungs of HIF-1α(+/-) mice. In contrast, a short duration of SMAO (15 min) followed by 3 h of reperfusion neither induced mucosal HIF-1α protein levels nor caused significant gut and lung injury in wild-type or HIF-1α(+/-) mice. This study indicates that intestinal HIF-1 activation is a proximal regulator of I/R-induced gut mucosal injury and gut-induced lung injury. However, the duration and severity of the gut I/R insult dictate whether HIF-1 plays a gut-protective or deleterious role.  相似文献   

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Administration of propofol at the time of reperfusion has shown to protect the heart from ischemia and reperfusion (I/R) injury. The aim of the present study was to investigate the molecular mechanism underling the cardioprotective effect of propofol against myocardial I/R injury (MIRI) in vivo and in vitro. Rat heart I/R injury was induced by ligation of the left anterior descending (LAD) artery for 30 min followed by 2-hr reperfusion. Propofol pretreatment (0.01 mg/g) was performed 10 min before reperfusion. In vitro MIRI was investigated in cultured cardiomyocytes H9C2 following hypoxia/reoxygenation (H/R) injuries. Propofol pretreatment in vitro was achieved in the medium supplemented with 25 μmol/L propofol before H/R injuries. Propofol pretreatment significantly increased miRNA-451 expression, decreased HMGB1 expression, reduced infarct size, and I/R-induced cardiomyocyte apoptosis in rat hearts undergoing I/R injuries. Knockdown of miRNA-451 48 hr before I/R injury was found to increase HMGB1 expression, infarct size, and I/R-induced cardiomyocyte apoptosis in rat hearts in the presence of propofol pretreatment. These in vivo findings were reproduced in vivo that knockdown of miRNA-451 48 hr before H/R injuries increased HMGB1 expression and H/R-induced apoptosis in cultured H9C2 supplemented with propofol. In addition, luciferase activity assays and gain-of-function studies found that propofol could decrease HMGB1, the target of miRNA-541. Taken together our findings provide a first demonstration that propofol-mediated cardioprotection against MIRI is dependent of microRNA-451/HMGB1. The study provides a novel target to prevent I/R injury during propofol anesthesia.  相似文献   

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Temporal expression of chemokines is a crucial factor in the regulation of renal ischemia/reperfusion (I/R) injury and repair. Beside their role in the migration and activation of inflammatory cells to sites of injury, chemokines are also involved in other processes such as angiogenesis, development and migration of stem cells. In the present study we investigated the role of the chemokine MCP-1 (monocyte chemoattractant protein-1 or CCL2), the main chemoattractant for monocytes, during renal I/R injury. MCP-1 expression peaks several days after inducing renal I/R injury coinciding with macrophage accumulation. However, MCP-1 deficient mice had a significant decreased survival and increased renal damage within the first two days, i.e. the acute inflammatory response, after renal I/R injury with no evidence of altered macrophage accumulation. Kidneys and primary tubular epithelial cells from MCP-1 deficient mice showed increased apoptosis after ischemia. Taken together, MCP-1 protects the kidney during the acute inflammatory response following renal I/R injury.  相似文献   

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AimsRepetitive hypoxic preconditioning (RHP) may provide more efficient protection than single hypoxic preconditioning against renal ischemia/reperfusion-induced injury via hypoxia-induced factor 1α (HIF-1α)-dependent heat shock protein 70 (HSP70) pathways.Main methodsWistar rats were subjected to intermittent hypoxic exposure (15 h/day), whereas controls were kept at sea level. We evaluated renal expression of HIF-1α, HSP70, the endoplasmic reticulum stress protein GRP78, caspase 12, Beclin-1, and poly-(ADP-ribose)-polymerase (PARP) with western blotting. Renal apoptosis determined by terminal transferase dUTP nick end labeling (TUNEL), Beclin-1-dependent autophagy, and monocyte/macrophage (ED-1) infiltration were evaluated by immunocytochemistry. Renal function was determined with blood urea nitrogen (BUN) and plasma creatinine levels. HIF-1α inhibitors and Deoxyribonucleotide (DNA) or Ribonucleotide (RNA) interference of HSP70 were used to evaluate their possible roles in this process.Key findingsRenal HIF-1α and HSP70 expression were enhanced by hypoxic preconditioning and inhibited by the HIF-1α inhibitor, YC-1, as well as phosphatidylinositol 3-kinase (PI3K)/Akt inhibitors. After the return to normoxia, renal HSP70 protein levels were maintained for one week in the RHP group, but they decayed after one day in the single hypoxic preconditioning group. Ischemia/reperfusion significantly increased renal TUNEL-apoptosis, Beclin-1-dependent autophagy, ED-1 infiltration, expression of GRP78, caspase 12, Beclin-1, PARP, and BUN and plasma creatinine levels in control rats. RHP significantly decreased all ischemia/reperfusion-enhanced parameters. Intraperitoneal pretreatment with YC-1 and quercetin (an inhibitor of HSP70 induction) eliminated RHP-induced protection. Anti-sense oligodeoxyribonucleotides or interference RNA targeting HSP70 abrogated the protection against hypoxia/reoxygenation-induced oxidative injury in RHP-treated proximal tubules.SignificanceWe demonstrate that RHP promotes HIF-1α-dependent HSP70 signaling to reduce renal ischemia/reperfusion injury.  相似文献   

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NADPH oxidase plays a central role in mediating oxidative stress during heart, liver, and lung ischemia/reperfusion injury, but limited information is available about NADPH oxidase in renal ischemia/reperfusion injury. Our aim was to investigate the activation of NADPH oxidase in a swine model of renal ischemia/reperfusion damage. We induced renal ischemia/reperfusion in 10 pigs, treating 5 of them with human recombinant C1 inhibitor, and we collected kidney biopsies before ischemia and 15, 30, and 60 min after reperfusion. Ischemia/reperfusion induced a significant increase in NADPH oxidase 4 (NOX-4) expression at the tubular level, an upregulation of NOX-2 expression in infiltrating monocytes and myeloid dendritic cells, and 8-oxo-7,8-dihydro-2′-deoxyguanosine synthesis along with a marked upregulation of NADPH-dependent superoxide generation. This burden of oxidative stress was associated with an increase in tubular and interstitial expression of the myofibroblast marker α-smooth muscle actin (α-SMA). Interestingly, NOX-4 and NOX-2 expression and the overall NADPH oxidase activity as well as α-SMA expression and 8-oxo-7,8-dihydro-2′-deoxyguanosine synthesis were strongly reduced in C1-inhibitor-treated animals. In vitro, when we incubated tubular cells with the anaphylotoxin C3a, we observed an enhanced NADPH oxidase activity and α-SMA protein expression, which were both abolished by NOX-4 silencing. In conclusion, our findings suggest that NADPH oxidase is activated during ischemia/reperfusion in a complement-dependent manner and may play a potential role in the pathogenesis of progressive renal damage in this setting.  相似文献   

10.
HS Ding  J Yang  FL Gong  J Yang  JW Ding  S Li  YR Jiang 《Gene》2012,509(1):149-153
This study aimed to explore the role of high mobility box 1 (HMGB1) and its receptor toll like receptor 4 (TLR4) on neutrophils in myocardial ischemia reperfusion (I/R) injury. We constructed TLR4-mutant (C3H/HeJ) and control (C3H/HeN) mouse models of myocardial I/R injury and subjected the mice to 30min of ischemia and 6h of reperfusion. Light microscope was used to observe structural changes in the myocardium. HMGB1 levels were measured using quantitative real-time PCR and immunohistochemistry. Neutrophil accumulation, TNF-a expression and IL-8 levels were analyzed via myeloperoxidase (MPO) biochemical studies, quantitative real-time PCR and ELISA, respectively. The results demonstrated that fewer neutrophils infiltrated in the myocardium of TLR4-mutant mice after myocardial I/R and that TLR4 deficiency markedly decreased the ischemic injury caused by ischemia/reperfusion, and inhibited the expression of HMGB1, TNF-a, and IL-8, all of which were up-regulated by ischemia/reperfusion. These findings suggest that HMGB1 plays a central role in recruiting neutrophils during myocardial I/R leading to worsened myocardial I/R injury. This recruitment mechanism is possibly due to its inflammatory and chemokine functions based on the TLR4-dependent pathway.  相似文献   

11.
Angiogenic factor with G patch and FHA domains 1 (AGGF1) is a newly identified proangiogenic protein, which plays an important role in vascular disease and angiogenesis. However, its role in myocardial ischemia/reperfusion (I/R) injury remains unknown. This study investigated whether AGGF1 is involved in the pathogenesis of mouse myocardial I/R injury and the underlying mechanisms. Wild-type (WT) C57BL/6 J mice were treated at 30 min prior to I/R injury with anti-AGGF1 neutralizing antibody (3 mg/kg) or recombinant human AGGF1 (rhAGGF1, 0.25 mg/kg). After I/R injury, the infarct size, the number of TUNEL-positive cardiomyocytes, Bax/Bcl2 ratio, inflammatory cytokine expression and angiogenesis were markedly increased as compared with sham control. Treatment of WT mice with anti-AGGF1 neutralizing antibody resulted in exaggeration of myocardial I/R injury but reducing angiogenesis. In contrast, administration of rhAGGF1 markedly reversed these effects. Furthermore, anti-AGGF1- or rhAGGF1-mediated effects on I/R-induced cardiac apoptosis, inflammation and angiogenesis were dose dependent. In addition, the protective effects of AGGF1 on cardiomyocyte apoptosis and inflammation were confirmed in cultured cardiomyocytes after I/R. Finally, these effects were associated with activation of ERK1/2, Stat3 and HIF-1α/VEGF pathways and inhibition of activation of NF-κB, p53 and JNK1/2 pathways. In conclusion, we report the first in vivo and in vitro evidence that AGGF1 reduces myocardial apoptosis and inflammation and enhances angiogenesis, leading to decreased infarct size after I/R injury. These results may provide a novel therapeutic approach for ischemic heart diseases.  相似文献   

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Acidic microenvironment is commonly observed in ischaemic tissue. In the kidney, extracellular pH dropped from 7.4 to 6.5 within 10 minutes initiation of ischaemia. Acid‐sensing ion channels (ASICs) can be activated by pH drops from 7.4 to 7.0 or lower and permeates to Ca2+entrance. Thus, activation of ASIC1a can mediate the intracellular Ca2+ accumulation and play crucial roles in apoptosis of cells. However, the role of ASICs in renal ischaemic injury is unclear. The aim of the present study was to test the hypothesis that ischaemia increases renal epithelia cell apoptosis through ASIC1a‐mediated calcium entry. The results show that ASIC1a distributed in the proximal tubule with higher level in the renal tubule ischaemic injury both in vivo and in vitro. In vivo, Injection of ASIC1a inhibitor PcTx‐1 previous to ischaemia/reperfusion (I/R) operation attenuated renal ischaemic injury. In vitro, HK‐2 cells were pre‐treated with PcTx‐1 before hypoxia, the intracellular concentration of Ca2+, mitochondrial transmembrane potential (?ψm) and apoptosis was measured. Blocking ASIC1a attenuated I/R induced Ca2+ overflow, loss of ?ψm and apoptosis in HK‐2 cells. The results revealed that ASIC1a localized in the proximal tubular and contributed to I/R induced kidney injury. Consequently, targeting the ASIC1a may prove to be a novel strategy for AKI patients.  相似文献   

13.
Liu A  Fang H  Dirsch O  Jin H  Dahmen U 《Cytokine》2012,57(1):150-157
Macrophage migration inhibitory factor (MIF) is an important mediator of ischemia/reperfusion (I/R) injury in heart, brain and intestine. We previously demonstrated that MIF was released during warm/cold ischemia in vitro. However, the role of MIF in liver I/R injury remains unclear. We aimed to test the hypothesis that MIF acts as an early proinflammatory cytokine and could mediate the inflammatory injury in liver I/R. Rats (n = 6 per group) were subjected to 90 min warm ischemia followed by 0.5 h, 6 h and 24 h reperfusion, respectively to liver transplantation (LTx) after 6 h of cold ischemia followed by 24 h of reperfusion. The expression of MIF, its receptor (cluster of differentiation 74 (CD74)) and the downstream inflammatory cytokines (tumor necrosis factor-alpha (TNF-α) and interleukin-1 beta (IL-1β)) were analyzed. Peritoneal macrophages were cultured for 6 h alone or in the presence of effluent from cold-preserved livers or effluent depleted of MIF. Warm I/R increased hepatic MIF-mRNA and protein expression. MIF-protein was released into peripheral circulation in vivo with a maximum at 0.5 h after reperfusion. Induction of MIF-expression was associated with the expression of proinflammatory cytokines and its receptor in both models. MIF released by isolated cold preserved livers, induced TNF-α and IL-1β production by cultured peritoneal macrophages. Intrahepatic upregulation of MIF, release into systemic circulation and the associated upregulation of the proinflammatory mediators suggest a role of MIF in mediating the inflammatory response to I/R injury. Blocking experiments will help to elucidate its role as potential molecular target for preventing hepatic I/R injury.  相似文献   

14.

Background

Hypoxia-inducible factor-1α (HIF-1α) is overexpressed in many human tumors and their metastases, and is closely associated with a more aggressive tumor phenotype. The aim of the present study was to investigate the effect of resveratrol (RES) on the expression of ischemic-induced HIF-1α and vascular endothelial growth factor (VEGF) in rat liver.

Methods

Twenty-four rats were randomized into Sham, ischemia/reperfusion (I/R), and RES preconditioning groups. I/R was induced by portal pedicle clamping for 60 minutes followed by reperfusion for 60 minutes. The rats in RES group underwent the same surgical procedure as I/R group, and received 20 mg/kg resveratrol intravenously 30 min prior to ischemia. Blood and liver tissue samples were collected and subjected to biochemical assays, RT-PCR, and Western blot assays.

Results

I/R resulted in a significant (P<0.05) increase in liver HIF-1α and VEGF at both mRNA and protein levels 60 minutes after reperfusion. The mRNA and protein expressions of HIF-1α and VEGF decreased significantly in RES group when compared to I/R group (P<0.05).

Conclusion

The inhibiting effect of RES on the expressions of HIF-1α and VEGF induced by I/R in rat liver suggested that HIF-1α/VEGF could be a promising drug target for RES in the development of an effective anticancer therapy for the prevention of hepatic tumor growth and metastasis.  相似文献   

15.
Zhang ZY  Liu XH  Guo XS  Liu FY 《生理学报》2007,59(5):643-650
本实验分别在整体和细胞水平观察缺血后处理(ischemic postconditioning,I-postC)对骨骼肌缺血/再灌注(ischemia/reperfusion,I/R)损伤的影响,并探讨钙网蛋白(calreticulin,CRT)介导的信号转导机制。(1)整体实验:健康雄性Wistar大鼠48只,无创动脉夹夹闭右侧股动脉4h,松夹再灌注12h或24h建立大鼠右后肢I/R损伤模型,随机分为I/R组、缺血预处理(ischemic preconditioning,IPC)组(5min缺血/5min再灌,3个循环)和I-postC组(1min再灌/1min缺血,3个循环)(n=16),大鼠左后肢做对照处理。再灌注结束时测定血浆乳酸脱氢酶(1actate dehydrogenase,LDH)活性、骨骼肌湿干重比值(wet/dryweightratio,W/D);电镜观察骨骼肌超微结构变化:Westernblot检测骨骼肌CRT、钙调神经磷酸酶(calcineurin,CaN)的表达。(2)细胞培养实验:原代培养Sprague-Dawley乳鼠骨骼肌细胞,随机分为6组:正常对照组、缺氧/复氧(hypoxia/reoxygenation,H/R)组、缺氧预处理(hypoxic preconditioning,HPC)组、缺氧后处理(hypoxic postconditioning,H-postC)组、CaN抑制剂环孢素A(cyclosporine,CsA)+H/R组和CsA+H-postC组。台盼蓝排斥实验、流式细胞仪检测细胞损伤情况:Westernblot检测骨骼肌细胞CRT和CaN的表达。结果显示:(1)在整体动物实验中,I-postC可显著降低血浆LDH活性和组织水肿,骨骼肌超微结构损伤减轻,无细胞核凋亡现象,与IPC组相比无显著差异。I-postC再灌注12h和24hCRT表达分别较I/R12h和24h组高4.39倍和1.02倍(P〈0.05),CaN表达分别增高1.96倍和0.63倍(尸〈0.05)。相关分析显示CRT表达与CaN表达呈正相关(r-0.865,P〈0.01)。(2)在细胞培养实验中,H-postC可减轻H/R诱导的骨骼肌细胞凋亡,增加细胞存活率,与HPC组相比无显著差异,CsA可抑制H-postC的保护作用;H-postC可上调CRT和CaN的表达,分别较H/R组增加31.8%(P〈0.05)和6.02%,加入CsA后CaN表达降低44.02%(P〈0.05vsH-postC)。上述整体实验和细胞培养实验结果提示,I-postC与IPC保护作用相似,可显著减轻I/R损伤;CRT上调介导的CaN表达增加可能参与了I-postC的保护作用,抑制CaN表达可降低I-postC的保护作用。  相似文献   

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Whether ischemic postconditioning (IPC) can significantly alleviate ischemic injury hinges on the appropriate measure. In this study, the expression RGMa and IL-1β, IL-6 are investigated to estimate the therapeutic benefits of various postconditioning strategies after cerebral ischemia/reperfusion. The study consists of the sham-operated group and five treatment groups: ischemia/reperfusion (I/R), two proximate ischemic postconditioning (IPC-S and IPC-M), remote postconditioning (RIPC) and delayed postconditioning (DIPC) groups. We find that rats in IPC and RIPC groups exhibit significantly less neural deficit and lower infarct volume than that in I/R and DIPC groups after ischemia/reperfusion. Moreover, in ischemic cortex and hippocampus, the mRNA level of RGMa is much lower in IPC and RIPC groups. Immunohistochemical analysis indicates that the expression of RGMa, IL-1β and IL-6 are reduced in IPC and RIPC groups (especially in IPC-S group). Furthermore, neurofilament staining reveals that the rats in IPC and RIPC groups have less axonal injury than that in I/R and DIPC groups. Our studies suggest that the optimal strategy to attenuate cerebral ischemia/reperfusion is achieved by early, short-term, and multiple cycles of proximal IPC. The cerebral protective effect of IPC may be associated with the decreased expression of RGMa and inflammation mediators.  相似文献   

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Renal organic cation transporters are downregulated by nitric oxide (NO) in rat endotoxemia. NO generated by inducible NO synthase (iNOS) is substantially increased in the renal cortex after renal ischemia-reperfusion (I/R) injury. Therefore, we investigated the effects of iNOS-specific NO inhibition on the expression of the organic cation transporters rOct1 and rOct2 (Slc22a1 and Slc22a2, respectively) after I/R injury both in vivo and in vitro. In vivo, N(6)-(1-iminoethyl)-L-lysine (L-NIL) completely inhibited NO generation after I/R injury. Moreover, L-NIL abolished the ischemia-induced downregulation of rOct1 and rOct2 as determined by qPCR and Western blotting. Functional evidence was obtained by measuring the fractional excretion (FE) of the endogenous organic cation serotonin. Concordant with the expression of the rate-limiting organic cation transporter, the FE of serotonin decreased after I/R injury and was totally abolished by L-NIL. In vitro, ischemia downregulated both rOct1 and rOct2, which were also abolished by L-NIL; the same was true for the uptake of the organic cation MPP. We showed that renal I/R injury downregulates rOct1 and rOct2, which is most probably mediated via NO. In principle, this may be an autocrine effect of proximal tubular epithelial cells. We conclude that rOct1, or rOct1 and rOct2 limit the rate of the renal excretion of serotonin.  相似文献   

20.
Renal ischaemia/reperfusion (I/R) injury may induce kidney damage and dysfunction, in which oxidative stress and apoptosis play important roles. Long noncoding RNAs (lncRNAs) and microRNAs (miRNAs) are reported to be closely related to renal I/R, but the specific molecular mechanism is still unclear. The purpose of this research was to explore the regulatory effect of lncRNA TUG1 on oxidative stress and apoptosis in renal I/R injury. This research revealed that in renal I/R injury and hypoxia/reperfusion (H/R) injury in vitro, the expression level of lncRNA TUG1 was upregulated, and oxidative stress levels and apoptosis levels were negatively correlated with the expression level of lncRNA TUG1. Using bioinformatics databases such as TargetScan and microRNA.org, microRNA-144-3p (miR-144-3p) was predicted to be involved in the association between lncRNA TUG1 and Nrf2. This study confirmed that the level of miR-144-3p was significantly reduced following renal I/R injury and H/R injury in vitro, and miR-144-3p was determined to target Nrf2 and inhibit its expression. In addition, lncRNA TUG1 can reduce the inhibitory effect of miR-144-3p on Nrf2 by sponging miR-144-3p. In summary, our research shows that lncRNA TUG1 regulates oxidative stress and apoptosis during renal I/R injury through the miR-144-3p/Nrf2 axis, which may be a new treatment target for renal I/R injury.  相似文献   

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