Role of adhesion molecules and dendritic cells in rat hepatic/renal ischemia-reperfusion injury and anti-adhesive intervention with anti-P-selectin lectin-EGF domain monoclonal antibody

AIM: To investigate the role of P-selectin, intercellular adhesion molecule-1 (ICAM-1) and dendritic cells (DCs)in liver/kidney of rats with hepatic/renal ischemiareperfusion injury and the preventive effect of anti-Pselectin lectin-EGF domain monoclonal antibody (anti-PsLEGFmAb) on the injury.METHODS: Rat models of hepatic and renal ischemiareperfusion were established. The rats were then divided into two groups, one group treated with anti-PsL-EGFmAb(n = 20) and control treated with saline (n = 20). Both groups were subdivided into four groups according to reperfusion time (1, 3, 6 and 24 h). The sham-operated group (n = 5) served as a control group. DCs were observed by the microscopic image method, while P-selectin and ICAM-1 were analyzed by immunohistochemistry.RESULTS: P-selectin increased significantly in hepatic sinusoidal endothelial cells and renal tubular epithelial cells 1 h after ischemia-reperfusion, and the expression of ICAM-1 was up-regulated in hepatic sinusoid and renal vessels after 6 h. CD1a+CD80+DCs gradually increased in hepatic sinusoidal endothelium and renal tubules and interstitium 1 h after ischemia-reperfusion, and there was the most number of DCs in 24-h group. The localization of DCs was associated with rat hepatic/renal function.These changes became less significant in rats treated with anti-PsL-EGFmAb.CONCLUSION: DCs play an important role in immune pathogenesis of hepatic/renal ischemia-reperfusion injury.Anti-PsL-EGFmAb may regulate and inhibit local DC immigration and accumulation in liver/kidney.

Bioinformatics Analysis of Genes and Pathways of CD11b^(+)/Ly6C^(intermediate)Macrophages after Renal Ischemia-Reperfusion Injury

Renal ischemia-reperfusion injury(IRI)is a major cause of acute kidney injury(AKI),which could induce the poor prognosis.The purpose of this study was to characterize the molecular mechanism of the functional changes of CD11 b^(+)/Ly6 C^(intermediate)macrophages after renal IRI.The gene expression profiles of CD11 b^(+)/Ly6 C^(intermediate)macrophages of the sham surgery mice,and the mice 4 h,24 h and 9 days after renal IRI were downloaded from the Gene Expression Omnibus database.Analysis of m RNA expression profiles was conducted to identify differentially expressed genes(DEGs),biological processes and pathways by the series test of cluster.Protein-protein interaction network was constructed and analysed to discover the key genes.A total of 6738 DEGs were identified and assigned to 20 model profiles.DEGs in profile 13 were one of the predominant expression profiles,which are involved in immune cell chemotaxis and proliferation.Signet analysis showed that Atp5 a1,Atp5 o,Cox4 i,Cdc42,Rac2 and Nhp2 were the key genes involved in oxidation-reduction,apoptosis,migration,M1-M2 differentiation,and proliferation of macrophages.RPS18 may be an appreciate reference gene as it was stable in macrophages.The identified DEGs and their enriched pathways investigate factors that may participate in the functional changes of CD11 b^(+)/Ly6 C^(intermediate)macrophages after renal IRI.Moreover,the vital gene Nhp2 may involve the polarization of macrophages,which may be a new target to affect the process of AKI.

Role of P-selectin and anti-P-selectin monoclonal antibody in apoptosis during hepatic/renal ischemia-reperfusion injury

AIM To evaluale the potential role of P-selectinand anti-P-selectin monoclonal antibody(mAb)in apoptosis during hepatic/renal ischemia-reperfusion injury.METHODS Plasma P-selectin level,hepatic/renal P-selectin expression and cell apoptosiswere detected in rat model of hepatic/ renalischemia-reperfusion injury.ELISA,immunohist-ochemistry and TUNEL were used.Someischemia-reperfusion rats were treated with anti-P-selectin mAb.RESULTS Hepatic/renal function insuffic-iency,up-regulated expression of P-selectin inplasma and hepatic/renal tissue,hepatic/renalhistopathological damages and cell apoptosiswere found in rats with hepatic/renal ischemia-reperfusion injury,while these changes becameless conspicuous in animals treated with anti-P-selectin mAb.CONCLUSION P-selectin might mediateneutrophil infiltration and cell apoptosis andcontribute to hepatic/renal ischemia-reperfusioninjury,anti-P-selectin mAb might be an efficientapproach for the prevention and treatment ofhepatic/renal ischemia-reperfusion injury.

Fenofibrate Pre-treatment Suppressed Inflammation by Activating Phosphoinositide 3 Kinase/Protein Kinase B(PI3K/Akt) Signaling in Renal Ischemia-Reperfusion Injury

The aim of this study was to investigate the possible beneficial effects of Fenofibrate on renal ischemia-reperfusion injury（IRI） in mice and its potential mechanism. IRI was induced by bilateral renal ischemia for 60 min followed by reperfusion for 24 h. Eighteen male C57BL/6 mice were randomly divided into three groups： sham-operated group（sham）, IRI＋saline group（IRI group）, IRI＋Fenofibrate（FEN） group. Normal saline or Fenofibrate（3 mg/kg） was intravenously injected 60 min before renal ischemia in IRI group and FEN group, respectively. Blood samples and renal tissues were collected at the end of reperfusion. The renal function, histopathologic changes, and the expression levels of pro-inflammatory cytokines [interleukin-8（IL-8）, tumor necrosis factor alpha（TNF-α） and IL-6] in serum and renal tissue homogenate were assessed. Moreover, the effects of Fenofibrate on activating phosphoinositide 3 kinase/protein kinase B（PI3K/Akt） signaling and peroxisome proliferator-activated receptor-α（PPAR-α） were also measured in renal IRI. The results showed that plasma levels of blood urea nitrogen and creatinine, histopathologic scores and the expression levels of TNF-α, IL-8 and IL-6 were significantly lower in FEN group than in IRI group. Moreover, Fenofibrate pretreatment could further induce PI3K/Akt signal pathway and PPAR-α activation following renal IRI. These findings indicated PPAR-α activation by Fenofibrate exerts protective effects on renal IRI in mice by suppressing inflammation via PI3K/Akt activation. Thus, Fenofibrate could be a novel therapeutic alternative in renal IRI.

Extraction and Identification of Ginsenoside Re and Its Effects and Mechanism of Protecting Acute Renal Ischemia-reperfusion Injury in Rats

This paper studies the extraction and identification of ginsenoside Re from ginseng fruits and investigates the effect and mechanism of ginsenoside Re of protecting acute renal ischemia-reperfusion injury in rats.Having been smashed,the ginseng fruits were ultrasonically extracted twice with 95% ethanol for 30min each.Having been concentrated,the solution was dissolved with distilled water and separated by two-column chromatography,of which one was packed with macroporous resin D4020,and the other was packed with macroporous resin D941.The raw product was dissolved with methanol and was purified by elution on a Si gel column,finally ginsenoside Re was obtained.The structure of the ginsenoside Re was analyzed by the thin-layer chromatography and NMR methods,and HPLC was carried for the content determination.The model of acute renal ischemia-reperfusion injury in rats was established after ischemia for 1 h and reperfusion for 1 h or 24 h,serum SOD（superoxide dismutase）,MDA（malondialdehyde） and plasma TXB2（thromboxane B2） and 6-keto-PGF1α were detected.The results show that it has accurately,fast,convenient merits and so on.Ginsenoside Re has a protective effect on acute renal ischemia-reperfusion injury in rats,the mechanism may be related to improving the imbalance of thromboxane A2（TXA2）/prostacyclin（PGI2） and inhibiting lipid peroxidation reaction.

Antioxidative effect of peroxiredoxin-3 in the rat myocardium exposed to renal ischemia-reperfusion injury

Background:Peroxiredoxin-3(Prx-3)is known to be involved in the clearance of cellular hydrogen peroxide and plays an important role in protecting the myocardial tissue against damage of oxidative stress.However,the role of Prx-3 in protecting the myocardial tissue against renal ischemia/reperfusion(I/R)-induced myocardial injury(RI/RMI)remains unknown.We aimed to examine the antioxidative effect of Prx-3 using a rat RI/RMI model in an attempt to find a new approach to the prevention and treatment of myocardial injury induced by renal I/R.Methods:A RI/RMI rat model was established to detect the renal histopathology and renal functions by hematoxylin-eosin staining staining and commercially available assay kits.The myocardial antioxidant activity and the expressions of mRNA and protein of Prx-3 in the myocardial tissue were measured by real-time polymerase chain reaction and Western blotting assay,respectively.Results:Compared with the normal and control groups,the serum level of blood urea nitrogen and serum creatinine was significantly increased in the I/R group(P<0.05).Histopathological changes in the kidneys were also more obvious,including glomerular cystic and renal interstitial hemorrhage,renal tubular epithelial cell edema,and tubular type formation.The mRNA and protein expressions of Prx-3 were increased significantly in the RI/MRI rat model as compared with those in the normal and control groups.Conclusion:Oxidative damage occurred in the remote myocardium after renal I/R and Prx-3 was able to enhance the self-regulatory ability of the myocardium against damage from oxidative stress after RI/MRI.

Bioprinted mesenchymal stem cell microfiber-derived extracellular vesicles alleviate unilateral renal ischemia-reperfusion injury and fibrosis by inhibiting tubular epithelial cells ferroptosis

Renal unilateral ischemia-reperfusion injury(UIRI)constitutes a significant global health challenge,with poor recovery leading to chronic kidney disease and subsequent renal fibrosis.Extracellular vesicles(EVs)present substantial potential benefits for renal diseases.However,the limited yield and efficacy of EVs produced through traditional methodologies(2D-EVs)severely restrict their widespread application.Moreover,the efficient and effective strategies for using EVs in UIRI treatment and their mechanisms remain largely unexplored.In this study,we propose an innovative approach by integrating bioprinted mesenchymal stem cell microfiber extracellular vesicles production technology(3D-EVs)with a tail vein injection method,introducing a novel treatment strategy for UIRI.Our comparison of the biological functions of 2D-EVs and 3D-EVs,both in vitro and in vivo,reveals that 3D-EVs significantly outperform 2D-EVs.Specifically,in vitro,3D-EVs demonstrate a superior capacity to enhance the proliferation and migration of NRK-52E cells and mitigate hypoxia/reoxygenation(H/R)-induced injuries by reducing epithelial-mesenchymal transformation,extracellular matrix deposition,and ferroptosis.In vivo,3D-EVs exhibit enhanced therapeutic effects,as evidenced by improved renal function and decreased collagen deposition in UIRI mouse kidneys.We further elucidate the mechanism by which 3D-EVs derived from KLF15 ameliorate UIRI-induced tubular epithelial cells(TECs)ferroptosis through the modulation of SLC7A11 and GPX4 expression.Our findings suggest that bioprinted mesenchymal stem cells microfiberderived EVs significantly ameliorate renal UIRI,opening new avenues for effective and efficient EV-based therapies in UIRI treatment.

Inhibition of the cGAS–STING pathway:contributing to the treatment of cerebral ischemia-reperfusion injury

The cGAS–STING pathway plays an important role in ischemia-reperfusion injury in the heart,liver,brain,and kidney,but its role and mechanisms in cerebral ischemia-reperfusion injury have not been systematically reviewed.Here,we outline the components of the cGAS–STING pathway and then analyze its role in autophagy,ferroptosis,cellular pyroptosis,disequilibrium of calcium homeostasis,inflammatory responses,disruption of the blood–brain barrier,microglia transformation,and complement system activation following cerebral ischemia-reperfusion injury.We further analyze the value of cGAS–STING pathway inhibitors in the treatment of cerebral ischemia-reperfusion injury and conclude that the pathway can regulate cerebral ischemia-reperfusion injury through multiple mechanisms.Inhibition of the cGAS–STING pathway may be helpful in the treatment of cerebral ischemia-reperfusion injury.

HSP110 aggravates ischemia-reperfusion injury after liver transplantation by promoting NF-κB pathway

Background:Ischemia-reperfusion injury(IRI)poses a significant challenge to liver transplantation(LT).The underlying mechanism primarily involves overactivation of the immune system.Heat shock protein 110(HSP110)functions as a molecular chaperone that helps stabilize protein structures.Methods:An IRI model was established by performing LT on Sprague-Dawley rats,and HSP110 was silenced using siRNA.Hematoxylin-eosin staining,TUNEL,immunohistochemistry,ELISA and liver enzyme analysis were performed to assess IRI following LT.Western blotting and quantitative reverse transcription-polymerase chain reaction were conducted to investigate the pertinent molecular changes.Results:Our findings revealed a significant increase in the expression of HSP110 at both the mRNA and protein levels in the rat liver following LT(P<0.05).However,when rats were injected with siRNAHSP110,IRI subsequent to LT was notably reduced(P<0.05).Additionally,the levels of liver enzymes and inflammatory chemokines in rat serum were significantly reduced(P<0.05).Silencing HSP110 with siRNA resulted in a marked decrease in M1-type polarization of Kupffer cells in the liver and downregulated the NF-κB pathway in the liver(P<0.05).Conclusions:HSP110 in the liver promotes IRI after LT in rats by activating the NF-κB pathway and inducing M1-type polarization of Kupffer cells.Targeting HSP110 to prevent IRI after LT may represent a promising new approach for the treatment of LT-associated IRI.

Polydatin ameliorates hepatic ischemia-reperfusion injury by modulating macrophage polarization

Background:Polydatin,a glucoside of resveratrol,has shown protective effects against various diseases.However,little is known about its effect on hepatic ischemia-reperfusion(I/R)injury.This study aimed to elucidate whether polydatin protects liver against I/R-induced injury and to explore the underlying mechanism.Methods:After gavage feeding polydatin once daily for a week,mice underwent a partial hepatic I/R procedure.Serum alanine aminotransferase(ALT)/aspartate aminotransferase(AST),hematoxylin-eosin(H&E)and TdT-mediated dUTP nick-end labeling(TUNEL)staining were used to evaluate liver injury.The severity related to the inflammatory response and reactive oxygen species(ROS)production was also investigated.Furthermore,immunofluorescence and Western blotting were used to detect macrophage polarization and the NF-κB signaling pathway in macrophages.Results:Compared with the I/R group,polydatin pretreatment significantly attenuated I/R-induced liver damage and apoptosis.The oxidative stress marker(dihydroethidium fluorescence,malondialdehyde,superoxide dismutase and glutathione peroxidase)and I/R related inflammatory cytokines(interleukin1β,interleukin-10 and tumor necrosis factor-α)were significantly suppressed after polydatin treatment.In addition,the result of immunofluorescence indicated that polydatin reduced the polarization of macrophages toward M1 macrophages both in vivo and in vitro.Western blotting showed that polydatin inhibited the pro-inflammatory function of RAW264.7 via down-regulating the NF-κB signaling pathway.Conclusions:Polydatin protects the liver from I/R injury by remodeling macrophage polarization via NFκB signaling.

Gamma-aminobutyric acid enhances miR-21-5p loading into adipose-derived stem cell extracellular vesicles to alleviate myocardial ischemia-reperfusion injury via TXNIP regulation

BACKGROUND Myocardial ischemia-reperfusion injury(MIRI)poses a prevalent challenge in current reperfusion therapies,with an absence of efficacious interventions to address the underlying causes.AIM To investigate whether the extracellular vesicles(EVs)secreted by adipose mesenchymal stem cells(ADSCs)derived from subcutaneous inguinal adipose tissue(IAT)underγ-aminobutyric acid(GABA)induction(GABA-EVs^(IAT))demonstrate a more pronounced inhibitory effect on mitochondrial oxidative stress and elucidate the underlying mechanisms.METHODS We investigated the potential protective effects of EVs derived from mouse ADSCs pretreated with GABA.We assessed cardiomyocyte injury using terminal deoxynucleotidyl transferase dUTP nick end-labeling and Annexin V/propidium iodide assays.The integrity of cardiomyocyte mitochondria morphology was assessed using electron microscopy across various intervention backgrounds.To explore the functional RNA diversity between EVs^(IAT)and GABA-EVs^(IAT),we employed microRNA(miR)sequencing.Through a dual-luciferase reporter assay,we confirmed the molecular mechanism by which EVs mediate thioredoxin-interacting protein(TXNIP).Western blotting and immunofluorescence were conducted to determine how TXNIP is involved in mediation of oxidative stress and mitochondrial dysfunction.RESULTS Our study demonstrates that,under the influence of GABA,ADSCs exhibit an increased capacity to encapsulate a higher abundance of miR-21-5p within EVs.Consequently,this leads to a more pronounced inhibitory effect on mitochondrial oxidative stress compared to EVs from ADSCs without GABA intervention,ultimately resulting in myocardial protection.On a molecular mechanism level,EVs regulate the expression of TXNIP and mitigating excessive oxidative stress in mitochondria during MIRI process to rescue cardiomyocytes.CONCLUSION Administration of GABA leads to the specific loading of miR-21-5p into EVs by ADSCs,thereby regulating the expression of TXNIP.The EVs derived from ADSCs treated with GABA effectively ameliorates mitochondrial oxidative stress and mitigates cardiomyocytes damage in the pathological process of MIRI.

Network pharmacology investigation of the mechanism underlying the therapeutic action of Shikang granules in retinal ischemia-reperfusion injuries

Background:Retinal ischemia/reperfusion(I/R)injury often results in vision loss,and effective clinical management options are currently lacking.Shikang granules(SKG)are traditional Chinese medicine-based preparations commonly used in clinical practice for treating optic atrophy.Methods:Despite decades of clinical use,the precise mechanism of action(MoA)of SKG remains elusive.Here,we employ a network pharmacological approach to elucidate its MoA by identifying active ingredients and relevant targets using the Traditional Chinese Medicine System Pharmacology Database and Analytical Platform.Targets associated with retinal I/R injury were sourced from GeneCards,Online Mendelian Inheritance in Man,and DisGeNET.Venny software facilitated the identification of intersecting targets,which were then subjected to gene ontology functional analysis and Kyoto Encyclopedia of Genes and Genomes pathway analysis.To validate the protective effect and explore the MoA of SKG in retinal I/R injuries,we conducted experiments using rat models.Results:Our animal experiments demonstrated that SKG mitigated apoptosis following retinal I/R injury by upregulating the expression of the anti-apoptotic protein Bcl-2 and downregulating the expression of BAX,Caspase-9,Caspase-3,PARP,and cytochrome C.Additionally,SKG was found to increase the expression of PI3K and AKT.Conclusions:SKG may exert its protective effects by inhibiting apoptosis through modulation of pro-apoptotic and anti-apoptotic protein expression,as well as activation of the PI3K/AKT pathway.

Preliminary study on the protective effect of electroacupuncture Neiguan acupoint pretreatment on rats with myocardial ischemia-reperfusion injury:role of the miR-214-3p/NCX1 axis

Background:Ischemia-reperfusion can worsen myocardial damage and increase the risk of death.Studies have revealed that ischemic preconditioning provides the best endogenous protection against myocardial ischemia-reperfusion injury(MIRI),and the principle of electroacupuncture(EA)preconditioning is comparable to that of myocardial ischemic preconditioning adaption.Our earlier research demonstrated that EA pretreatment inhibits the expression of calmodulin-dependent protein kinase IIδ(CaMKIIδ),sodium/calcium exchanger 1(NCX1),and cyclophilin D,hence providing protection against MIRI.However,the exact mechanism is still unknown.The expression of NCX1 mRNA is directly regulated by microRNA-214(miR-214).Moreover,it suppresses the levels of CaMKIIδand cyclophilin D.Whether these variables contribute to EA preconditioning to improve MIRI needs to be investigated,though.This study aimed to preliminarily determine whether EA pretreatment ameliorates MIRI by modulating the miR-214-3p/NCX1 axis.Methods:We used a rat MIRI model to investigate the effect of EA pretreatment on MIRI and the expression of miR-214-3p.In addition,adenovirus injection inhibited miR-214-3p expression in the rat MIRI model,and the influence of EA pretreatment towards MIRI was observed in the context of blocked miR-214-3p expression.Both the myocardial histological abnormalities and the alterations in the ST segment of the rat electrocardiogram were analyzed.NCX1 mRNA,cyclophilin D,and CaMKIIδexpression levels were also analyzed.Results:EA pretreatment improved MIRI.In rats with MIRI,EA administration increased miR-214-3p expression while decreasing NCX1 mRNA,cyclophilin D,and CaMKIIδproteins in cardiac tissues.The beneficial effect of EA pretreatment against MIRI was reversed,coupled with elevated levels of NCX1 mRNA,cyclophilin D,and CaMKIIδprotein expression,when an adenovirus injection disrupted the expression of miR-214-3p.Conclusions:Our findings preliminarily show that EA pretreatment inhibits the expression of NCX1 mRNA,cyclophilin D,and CaMKIIδproteins via miR-214-3p,hence exerting MIRI protection.

The mechanisms that regulate neuronal pyroptosis in cerebral ischemia-reperfusion injury:current theories and recent advances

Early or ultra-early pharmacological thrombolysis together with mechanical thrombectomy are key treatments for ischemic stroke,and both are aimed at vascular recanalization and improved collateral circulation.While these methods enhance tissue perfusion in the ischemic penumbra,they also trigger complex neurotoxic reactions,including apoptosis,acidosis,ion imbalance,oxidative stress,and pyroptosis,exacerbating cerebral ischemia-reperfusion injury(CIRI).Pyroptosis,a recently discovered form of programmed cell death driven by inflammation,plays a significant role in neuronal death during CIRI.This study reviews the regulatory mechanisms of pyroptosis in CIRI.

Protective Effects and Mechanisms of Shenhua Tablet(肾华片)on Toll-Like Receptors in Rat Model of Renal Ischemia-Reperfusion Injury

Objective: To investigate the protective effects and potential mechanisms of Shenhua Tablet(肾华片, SHT) on the toll-like receptors(TLRs)-mediated signaling pathways in a rat model of kidney ischemia-reperfusion injury(IRI). Methods: Sixty male Wistar rats were randomly divided into 5 groups: sham surgery, model control, astragaloside(150 mg·kg^(-1)·d^(-1)), low-and high-dose SHT(1.5 and 3.0 g·kg^(-1)·d^(-1), repectively) groups. One week after drug treatment, rats underwent surgery to establish the IRI models. At 24 h and 72 h after the modeling, serum creatinine(Scr) and blood urea nitrogen(BUN) were analyzed; pathological damage were scored after periodic acid-Schiff staining. TLR2, TLR4 and myeloid differentiation factor 88(My D88) protein and m RNA expressions were detected by inmmunohistochemistry, Western blot and qPCR. Tumor necrosis factor α(TNF-α) and interleukin-6(IL-6) protein expressions were detected by enzyme linked immunosorbent assay. Results: Compared with the sham group, the model group exhibited severe change in renal function(Scr: 189.42±21.50, P<0.05), pathological damage(damage score: 4.50±0.55, P<0.05), and the expression levels of TLR2, TLR4, MyD88, TNF-α, IL-6 were significantly higher than other groups. Meanwhile, the levels of TLRs in model group showed upward tendency from 24 to 72 h, unparalleled with pathological and functional changes. The aforementioned parameters were alleviated to a certain extent, and, in addition to TLRs, presented the obvious downward trending from the 24 to 72 h after the intervention in the SHT and astragaloside groups relative to the model(P<0.05); in particular, the most significant mitigation of these changes was observed in the SHT-H group(P<0.05). Conclusions: TLRs may be an important spot to treat and research in acute kidney injury. SHT could effectively mitigate renal injuries and promote recovery of IRI injuries through suppression of degeneration induced by up-regulation of TLR2 and TLR4 expression levels in the My D88-dependent signaling pathway and exhibit some dose dependence.

Critical hubs of renal ischemia-reperfusion injury:endoplasmic reticulum-mitochondria tethering complexes

Mitochondrial injury and endoplasmic reticulum(ER)stress are considered to be the key mechanisms of renal ischemia-reperfusion(I/R)injury.Mitochondria are membrane-bound organelles that form close physical contact with a specific domain of the ER,known as mitochondrial-associated membranes.The close physical contact between them is mainly restrained by ER-mitochondria tethering complexes,which can play an important role in mitochondrial damage,ER stress,lipid homeostasis,and cell death.Several ER-mitochondria tethering complex components are involved in the process of renal I/R injury.A better understanding of the physical and functional interaction between ER and mitochondria is helpful to further clarify the mechanism of renal I/R injury and provide potential therapeutic targets.In this review,we aim to describe the structure of the tethering complex and elucidate its pivotal role in renal I/R injury by summarizing its role in many important mechanisms,such as mitophagy,mitochondrial fission,mitochondrial fusion,apoptosis and necrosis,ER stress,mitochondrial substance transport,and lipid metabolism.

Protective effect of indomethacin in renal ischemia-reperfusion injury in mice

Objective： To evaluate the renoprotection effects of non-steroidal anti-inflammatory drugs （NSAIDs） in renal ischemia-reperfusion injury （IRI） and the cyclooxygenase （COX）-1/2 blockade association by indomethacin （IMT） in the mice model. Methods： After the left renal pedicle of mice was clamped, IMT was administrated by intraperitoneal injection with four doses： 1, 3, 5, and 7 mg/kg. Blood and kidney samples were collected 24 h after IRI. The renal functions were assayed by the cytokines and serum creatinine （SCr） using enzyme-linked immunosorbent assay （ELISA） kits. Kidney samples were analyzed by hematoxylin and eosin （H＆E） and immunohistochemistry stainings. Results： The mice administered with 5 mg/kg IMT had a marked reduction in SCr and significantly less tubular damage The tumor necrosis factor a （TNF-α） activity in renal homogenates and interleukin 6 （IL-6） activity in serum had a marked reduction at doses of 5 and 7 mg/kg IMT. The administration of 3 and 5 mg/kg IMT had a marked reduction in the ratio of thromboxane B2 to 6-keto-prostaglandin F1α. COX-1 and COX-2 stainings were weaker in 5 mg/kg IMT groups than that in the other groups. Conclusions： There was a dose response in the IMT function of renal IRI in mice, and IMT had a protective effect in a certain dose range. The effect of IMT on mice IRI was related to COX-1/2 blockades.

Heat shock pretreatment improves stem cell repair following ischemia-reperfusion injury via autophagy

AIM: To investigate whether heat shock pretreatment(HSP) improves mesenchymal stem cell(MSC) repair via autophagy following hepatic ischemia-reperfusion injury(HIRI).METHODS: Apoptosis of MSCs was induced by 250 m M hydrogen peroxide(H2O2) for 6 h. HSP was carried out using a 42 ℃ water bath for 1, 2 or 3 h. Apoptosis of MSCs was analyzed by flow cytometry, and Western blot was used to detect Bcl-2, Bax and cytochrome C expression. Autophagy of MSCs was analyzed by flow cytometry and transmission electron microscopy, and the expression of beclin Ⅰ?and LC3-Ⅱ was detected by Western blot. MSCs were labeled in vivo with the fluorescent dye, CM-Dil, and subsequently transplanted into the portal veins of rats that had undergone HIRI. Liver levels of proliferating cell nuclear antigen(PCNA) were quantified by fluorescent microscopy. Serum aminotransferase activity and the extent of HIRI were also assessed at each time point.RESULTS: HSP for 2 h reduced apoptosis of MSCs induced by H2O2 as seen by a decrease in apoptotic rate, a decrease in Bax and cytochrome C expression and an increase in Bcl-2 expression(P < 0.001). In addition, HSP for 2 h induced autophagy of MSCs exposed to H2O2 as shown by an increase in acidic vesicular organelle-positive cells, beclin 1 and LC3-Ⅱ expression, and autophagosome formation(P < 0.05). Treatment with 3-methyladenine attenuated HSPinduced autophagy and abolished the protective effects of HSP on the apoptosis of MSCs. Rapamycin failed to have additional effects on either autophagy or apoptosis compared with HSP alone. The phosphorylation of p38 MAPK was significantly elevated and the phosphorylation of m TOR was downregulated in heat shock pretreated MSCs. Treatment with the p38 MAPK inhibitor, SB203580, reduced HSP-induced autophagy in MSCs. In vivo studies showed that the transplantation of HSP-MSCs resulted in lower serum aminotransferase levels, lower Suzuki scores, improved histopathology and an increase in PCNA-positive cells(P < 0.05).CONCLUSION: HSP effectively induces autophagy following exposure to H2O2 via the p38MAPK/m TOR pathway, which leads to enhanced MSC survival and improved MSC repair following HIRI in rats.

The role and modulation of autophagy in experimental models of myocardial ischemia-reperfusion injury

A physiological sequence called autophagy qualitatively determines cellular viability by removing protein aggregates and damaged cyto-plasmic constituents, and contributes significantly to the degree of myocardial ischemia-reperfusion （I/R） injury. This tightly orchestrated cata-bolic cellular‘housekeeping’ process provides cells with a new source of energy to adapt to stressful conditions. This process was first described as a pro-survival mechanism, but increasing evidence suggests that it can also lead to the demise of the cell. Autophagy has been implicated in the pathogenesis of multiple cardiac conditions including myocardial I/R injury. However, a debate persists as to whether autophagy acts as a protec-tive mechanism or contributes to the injurious effects of I/R injury in the heart. This controversy may stem from several factors including the va-riability in the experimental models and species, and the methodology used to assess autophagy. This review provides updated knowledge on the modulation and role of autophagy in isolated cardiac cells subjected to I/R, and the growing interest towards manipulating autophagy to increase the survival of cardiac myocytes under conditions of stress-most notably being I/R injury. Perturbation of this evolutionarily conserved intracellular cleansing autophagy mechanism, by targeted modulation through, among others, mammalian target of rapamycin （mTOR） inhibitors, adenosine monophosphate-activated protein kinase （AMPK） modulators, calcium lowering agents, resveratrol, longevinex, sirtuin activators, the proapoptotic gene Bnip3, IP3 and lysosome inhibitors, may confer resistance to heart cells against I/R induced cell death. Thus, therapeutic ma-nipulation of autophagy in the challenged myocardium may benefit post-infarction cardiac healing and remodeling.

Mechanisms of hepatic ischemia-reperfusion injury and protective effects of nitric oxide

Hepatic ischemia-reperfusion injury(IRI) is a patho-physiological event post liver surgery or transplantation and significantly influences the prognosis of liver func-tion. The mechanisms of IRI remain unclear, and effec-tive methods are lacking for the prevention and therapy of IRI. Several factors/pathways have been implicated in the hepatic IRI process, including anaerobic metabo-lism, mitochondria, oxidative stress, intracellular cal-cium overload, liver Kupffer cells and neutrophils, and cytokines and chemokines. The role of nitric oxide(NO)in protecting against liver IRI has recently been report-ed. NO has been found to attenuate liver IRI through various mechanisms including reducing hepatocellular apoptosis, decreasing oxidative stress and leukocyte adhesion, increasing microcirculatory flow, and enhanc-ing mitochondrial function. The purpose of this review is to provide insights into the mechanisms of liver IRI, indicating the potential protective factors/pathways that may help to improve therapeutic regimens for control-ling hepatic IRI during liver surgery, and the potential therapeutic role of NO in liver IRI.