Protective role of retinoid X receptor in H9c2 cardiomyocytes from hypoxia/reoxygenation injury in rats

BACKGROUND: Retinoid X receptor(RXR) plays a central role in the regulation of intracellular receptor signaling pathways. The activation of RXR has protective effect on H2O2-induced apoptosis of H9c2 ventricular cells in rats. But the protective effect and mechanism of activating RXR in cardiomyocytes against hypoxia/reoxygenation(H/R)-induced oxidative iniury are still unclear.METHODS: The model of H/R injury was established through hypoxia for 2 hours and reoxygenation for 4 hours in H9c2 cardiomyocytes of rats. 9-cis-retinoic acid(9-cis RA) was obtained as an RXR agonist, and HX531 as an RXR antagonist. Cultured cardiomyocytes were randomly divided into four groups: sham group, H/R group, H/R+9-cis RA-pretreated group(100 nmol/L 9-cis RA), and H/R+9-cis RA+HX531-pretreated group(2.5 μmol/L HX531). The cell viability was measured by MTT, apoptosis rate of cardiomyocytes by flow cytometry analysis, and mitochondrial membrane potential(ΔΨm) by JC-1 fluorescent probe, and protein expressions of Bcl-2, Bax and cleaved caspase-9 with Western blotting. All measurement data were expressed as mean±standard deviation, and analyzed using one-way ANOVA and the Dunnett test. Differences were considered signif icant when P was <0.05.RESULTS: Pretreatment with RXR agonist enhanced cell viability, reduced apoptosis ratio, and stabled ΔΨm. Dot blotting experiments showed that under H/R stress conditions, Bcl-2 protein level decreased, while Bax and cleaved caspase-9 were increased. 9-cis RA administration before H/R stress prevented these effects, but the protective effects of activating RXR on cardiomyocytes against H/R induced oxidative injury were abolished when pretreated with RXR pan-antagonist HX531.CONCLUSION: The activation of RXR has protective effects against H/R injury in H9c2 cardiomyocytes of rats through attenuating signaling pathway of mitochondria apoptosis.

Aldehyde dehydrogenase 2 preserves mitochondrial morphology and attenuates hypoxia/reoxygenationinduced cardiomyocyte injury

BACKGROUND:Disturbance of mitochondrial fi ssion and fusion(termed mitochondrial dynamics)is one of the leading causes of ischemia/reperfusion(I/R)-induced myocardial injury.Previous studies showed that mitochondrial aldehyde dehydrogenase 2(ALDH2)conferred cardioprotective effect against myocardial I/R injury and suppressed I/R-induced excessive mitophagy in cardiomyocytes.However,whether ALDH2 participates in the regulation of mitochondrial dynamics during myocardial I/R injury remains unknown.METHODS:In the present study,we investigated the effect of ALDH2 on mitochondrial dynamics and the underlying mechanisms using the H9c2 cells exposed to hypoxia/reoxygenation(H/R)as an in vitro model of myocardial I/R injury.RESULTS:Cardiomyocyte apoptosis was significantly increased after oxygen-glucose deprivation and reoxygenation(OGD/R),and ALDH2 activation largely decreased the cardiomyocyte apoptosis.Additionally,we found that both ALDH2 activation and overexpression significantly inhibited the increased mitochondrial fission after OGD/R.Furthermore,we found that ALDH2 dominantly suppressed dynamin-related protein 1(Drp1)phosphorylation(Ser616)and adenosine monophosphate-activated protein kinase(AMPK)phosphorylation(Thr172)but not interfered with the expression levels of mitochondrial shaping proteins.CONCLUSIONS:We demonstrate the protective effect of ALDH2 against cardiomyocyte H/R injury with a novel mechanism on mitochondrial fission/fusion.

Effects of Crocin on Nox2 Expression and ROS Level of Hypoxia/Reoxygenation-induced Injury of Cardiomyocytes

[Objectives]To explore the protection mechanism of crocin against ischemia-reperfusion injury of myocardial cells.[Methods]Newborn male SD rats were selected,left ventricular cardiomyocytes(CMs)were isolated,and a hypoxia/reoxygenation model of CMs was established to simulate the process of ischemia/reperfusion injury.The cells were randomly divided into four groups:normal cell group(control group),crocin group),hypoxia/reoxygenation group(H/R group),hypoxia/reoxygenation+crocin group(H/R+crocin group).H/R+crocin group selected the concentration of crocin 1,10,and 100μmol/L,and determined the optimal concentration of crocin by detecting the cell proliferation ability.After the cells were pretreated using the optimal concentration of crocin,the levels of superoxide anion,cell proliferation,apoptosis and Nox2 levels in each group of cells were detected.[Results]Compared with the control group,the proliferation ability of CMs after hypoxia-reoxygenation injury was reduced(P<0.05),while cell apoptosis and intracellular superoxide anion levels were significantly increased(P<0.01);the CMs pretreated with crocin can reduce the level of Nox2(P<0.01),increase the cell proliferation ability of CMs,reduce cell apoptosis,and accordingly reduce the level of superoxide anion in the cell(P<0.05).[Conclusions]Crocin protects CMs from hypoxia/reoxygenation injury through down-regulating the level of Nox2 and reducing oxidative stress injury.

Effects of Cornus Officinal Is Total Glycoside on Cardiomyocyte Apoptosis and Calcium Overload after Hypoxia/Reoxygenation Injury in Rats

Objective: To investigate the mechanism of Cornus officinalis Total Glycosides (COTG) on myocardial protection, by studying effects of COTG on cardiomyocyte apoptosis induced by hypoxia/reoxygenation and calcium concentration in rats. Methods: The myocardial cells of born 1-3d SD rats were isolated by enzyme digestion, cultured for 3 days. Cells were divided into five groups: Control group, H/R group, Cornus officinalis Total Glycosides low-dose group (LDG), Cornus officinalis Total Glycosides middle-dose group (MDG) and Cornus officinalis Total Glycosides high-dose group (HDG). Three drug groups were pretreated with different doses of Cornus officinalis Total Glycosides before hypoxia/reoxygenation treatment. The apoptotic rate was determined by flow cytometry assay, the intracellular free calcium concentration was examined by flow cytometry, and the ultrastructure of myocardial cells was observed under transmission electron microscope. Results: The results revealed that Cornus officinalis Total Glycosides pretreatment decreased apoptosis rate, but the effect of lower dosage is not significant. Furthermore, Cornus officinalis Total Glycosides can attenuate mitochondrial calcium overload, improve mitochondrial morphology and inhibit cardiomyocyte apoptosis caused by H/R. Conclusion: Cornus officinalis Total Glycosides pretreatment can inhibit cardiomyocyte apoptosis and calcium overload during H/R injury. However, the underlying mechanisms require us to further study.

Neocryptotanshinone protects cardiomyocyte hypoxia/reoxygenation-induced H9C2 cell injury through targeting RxRα

OBJECTIVE Neocryptotanshinone(NCTS)is a natural product extracted from traditional Chinese herb Salvia miltiorrhiza Bunge.Previous studies have demonstrated the anti-inflammatory of NCTS in lipopolysaccharide(LPS)-stimulated mouse macrophage(RAW 264.7).However,the protective effect and mechanism of NCTS in cardiomy⁃ocytes are still undefined.This study is to investigate whether NCTS exerts its cardioprotective effect against hypoxia/re⁃oxygenation(H/R)-induced H9C2 cell injury.METHODS The model of H/R injury was established through hypoxia for 8 h and reoxygenation for 12 h in H9C2 cardiomyocytes of rats.Cultured cardiomyocytes were randomly divided into four groups,control group,H/R group,H/R+NCTS pretreated group(1,2,5 and 10μmol·L^-1),and H/R+NCTS+HX531(an RXRαantagonist,2μmol·L^-1)co-treated group.The cell viability was measured by Cell Counting Kit-8,Hoechst33258 staining was used to observe the morphology of apoptotic changes.Mitochondrial membrane potential was detected by JC-1 fluorescent probe,and protein expressions of RXRα,Bcl-2,Bax,caspase-3 and cleaved caspase-3 with Western blotting.RESULTS Compared with control group,the cell viability in model group was decreased(P<0.05).After treated with NCTS in different concentrations,the CCK8 results showed that NCTS in 2μmol·L^-1 had protective effects.Result of Hoechst33258 staining suggested that the apoptosis was notably increased in model group(P<0.05),Meanwhile,the JC-1 results showed that the mitochondrial membrane potential of the model group decreased which was consistent with previous study.impressively,NCTS could restore the mitochondrial membrane potential as well as apoptosis.Fur⁃ther western blot experiments showed that NCTS treat could upregulate Bcl-2 protein,and downregulate the levels of Bax and cleaved caspase-3/caspase-3 ratio.Since RXRαis a critical upstreaming proteins which can directly mediate the apoptosis,we then determined the effect of NCTS on it.Intriguingly,RXRαwas notably activated by NCTS,while the HX531,the antagonist of RXRα,could abolished NCTS'effect when co-treated with NCTS.CONCLUSION NCTS in 2μmol·L^-1 was effective to protect H9C2 cell from H/R-induced cell injury through RXRα-mediated mitochondria apop⁃tosis.Current results provide possible drugs for the treatment of ischemic cardiomyopathy.

Nonhematopoietic erythropoietin derivative protects cardiomyocytes from hypoxia/reoxygenation-induced apoptosis

Objective：Carbamylated EPO（CEPO） is a derivative of erythropoietin（EPO） by subjecting it to carbamylation. It does not stimulate erythropoiesis, but effectively protects tissue from injury. The present study was to investigate the effect of CEPO treatment using in vitro models of hypoxia/reoxygenation（H/R）. Methods：Cardiomyocytes were exposed to hypoxia（95% N2 and 5% CO2） for 1 hour followed by 4 hours of reoxygenation（95% O2 and 5% CO2）. CEPO was administered after hypoxia, just before reoxygenation. The apoptotic cardiomyocytes were determined by flow cytometry. The level of protein was assessed by western blot analysis. Results： CEPO treatment significantly decreased the apoptotic cardiomyocytes by 54.20% compared with H/R group. Western blot analysis showed that CEPO administration increased the level of Bcl-2（an antiapoptotic protein） by 62.22% compared with H/R group. Conclusion： Acute administration of CEPO protected cardiomyocytes from H/R-induced apoptosis. CEPO protected cardiomyocytes with a concomitant upregulation of Bcl-2 after H/R injury.

Effects of L-THP on Ca^(2+) Overload of Cultured Rat Cardiomyocytes during Hypoxia and Reoxygenation

The effects of L-tetrahydropalmatine (L-THP) on the cultured rat cardiomyocytes during hypoxia and reoxygenation and the mechanism of L-THP treating reperfusion-arrythmias were stud- ied. The concentration of intracellular free calcium ([Ca2+]i) of single cultured ventricular myocyte was determined by using EPC-9 light-electricity measurement system. It was found that L-THP (100μmol/L) could reduce the [Ca2+]i augmentation in single cultured ventricular myocyte during hypoxia and reoxygenation. Verapamil (10 μmol/L ) had the similar effect. It was concluded that L- THP could inhibit the Ca2+ overload of cultured rat cardiomyocytes during hypoxia and reoxygena- tion.

Protective effects of erythropoietin pretreatment on myocardium with hypoxia/reoxygenation injury in rats

Objective: To establish the rat model with myocardial hypoxia/reoxygenation (H/R) injury, and investigate the protective effect of EPO pretreatment on the myocardium. Methods: Sixty male adult Wistar rats were randomly divided into 3 groups: control group, H/R group, and EPO group, 20 in each group. The rats in EPO group accepted injection of 5 000 U/kg recombinant human erythropoietin (RHuEPO) through vein, and the other rats accepted the injection of the same volume of saline. Twenty-four hours after the injection, rats in the EPO and H/R groups were put into the hypoxia environment for 12 h and then returned to the normoxic environment for 2 h, and then the samples of blood and myocardium were collected. Serum myocardial enzyme activity, apoptosis, ultrastructure, myocardial MDA contents, EPO receptor (EPOR) expression in cardiac myocytes and cardiac functions were tested. Results: EPOR expression was positive in cardiac myocytes of adult rat according to the result of immunonistochemitry assaying. Compared to those in H/R group, rats in EPO group presented lighter injury of myocardial ultrastructure, the reduction of serum myocardial enzyme activity, inhibition of apoptosis, the better recovery of cardiac functions, and the less production of oxygen-derived free radicals. Conclusion: Adult rat cardiac myocytes could express EPOR, and EPO pretreatment produced protective effects on myocardium with H/R injury.

Propofol postconditioning ameliorates hypoxia/reoxygenation induced H9c2 cell apoptosis and autophagy via upregulating forkhead transcription factors under hyperglycemia

Background:Administration of propofol,an intravenous anesthetic with antioxidant property,immediately at the onset of post-ischemic reperfusion(propofol postconditioning,P-PostC) has been shown to confer cardioprotection against ischemia–reperfusion(I/R) injury,while the underlying mechanism remains incompletely understood.The forkhead box O(FoxO) transcription factors are reported to play critical roles in activating cardiomyocyte survival signaling throughout the process of cellular injuries induced by oxidative stress and are also involved in hypoxic postconditioning mediated neuroprotection,however,the role of FoxO in postconditioning mediated protection in the heart and in particular in high glucose condition is unknown.Methods:Rat heart-derived H9c2 cells were exposed to high glucose(HG) for 48 h,then subjected to hypoxia/reoxygenation(H/R,composed of 8 h of hypoxia followed by 12 h of reoxygenation) in the absence or presence of postconditioning with various concentrations of propofol(P-PostC) at the onset of reoxygenation.After having identified the optical concentration of propofol,H9c2 cells were subjected to H/R and P-PostC in the absence or presence of FoxO1 or FoxO3a gene silencing to explore their roles in P-PostC mediated protection against apoptotic and autophagic cell deaths under hyperglycemia.Results:The results showed that HG with or without H/R decreased cell viability,increased lactate dehydrogenase(LDH) leakage and the production of reactive oxygen species(ROS) in H9c2 cells,all of which were significantly reversed by propofol(P-PostC),especially at the concentration of 25 μmol/L(P25)(P<0.05,NC vs.HG;HG vs.HG+HR;HG+HR+P12.5 or HG+HR+P25 or HG+HR+P50 vs.HG+HR).Moreover,we found that propofol(P25) decreased H9c2 cells apoptosis and autophagy that were concomitant with increased FoxO1 and FoxO3a expression(P<0.05,HG+HR+P25 vs.HG+HR).The protective effects of propofol(P25) against H/R injury were reversed by silencing FoxO1 or FoxO3a(P<0.05,HG+HR+P25 vs.HG+HR+P25+siRNA-1 or HG+HR+P25+siRNA-5).Conclusions:It is concluded that propofol postconditioning attenuated H9c2 cardiac cells apoptosis and autophagy induced by H/R injury through upregulating FoxO1 and FoxO3a under hyperglycemia.

Effect of hypoxia/reoxygenation on the viability expression of ROS and MAPKs in myocardial cells

Objective:To investigate to the expression effect of hypoxia and hypoxia/reoxygenation on ROS,MAPKs and cell apoptosis in H9c2 cardiomyocytes.Methods:H9c2 cells were treated with cobalt chloride(CoCl2)to establish the chemical hypoxia and hypoxia/reoxygenation-induced cardiomyocyte injury model.CoCl2 was used to process cells at different concentrations from 150-2400μmol/L and different time from4-24 h;H9c2 cells viability was detected by MTT,and the intracellular ROS level was measured by 2’,7’-dichlorflμoresceindiacetate(DCFH-DA)and dihydroethidiμm(DHE)staining and photoflurography.The active expression level of mitogen-activated protein kinases(MAPKs)(including JNK,ERK and p38)and caspase-3.Results:At the concentration from 300 to 1200μmol/L,CoCl2 does/time-dependently inhibited the cell viability in H9c2 cells(P<0.01).Compared with control group,the ROS levels in hypoxia group were significantly increased(P<0.05).In hypoxia group,the active expression levels of p-JNK,p-p38 and caspase-3 was higher than those in control group(P<0.05).However,the expression of p-ERK wasn’t significant differernce.Furthermore,all the expression levels of ROS,p-JNK,p-ERK,p-p38 and caspase-3 in H/R group were significantly raised compared with hypoxia group(P<0.01).Conclusions:Reoxygenation further aggravate chemical hypoxia induced cardiomyocyte oxidative stress injury by activating ROS/MAPKs signals,suggesting the role of myocardial ischemia/reperfusion injury in the pathogenesis of ischemic heart disease.

Salvianolic Acid A Protects Neonatal Cardiomyocytes against Hypoxia/Reoxygenation-Induced Injury by Preserving Mitochondrial Function and Activating Akt/GSK-3β Signals

Objective: To investigate the effects of salvianolic acid A(SAA) on cardiomyocyte apoptosis and mitochondrial dysfunction in response to hypoxia/reoxygenation(H/R) injury and to determine whether the Akt signaling pathway might play a role. Methods: An in vitro model of H/R injury was used to study outcomes on primary cultured neonatal rat cardiomyocytes. The cardiomyocytes were treated with 12.5, 25, 50 μg/m L SAA at the beginning of hypoxia and reoxygenation, respectively. Adenosine triphospate(ATP) and reactive oxygen species(ROS) levels were assayed. Cell apoptosis was evaluated by flow cytometry and the expression of cleavedcaspase 3, Bax and Bcl-2 were detected by Western blotting. The effects of SAA on mitochondrial dysfunction were examined by determining the mitochondrial membrane potential(△Ψm) and mitochondrial permeability transition pore(m PTP), followed by the phosphorylation of Akt(p-Akt) and GSK-3β(p-GSK-3β), which were measured by Western blotting. Results: SAA significantly preserved ATP levels and reduced ROS production. Importantly, SAA markedly reduced the number of apoptotic cel s and decreased cleaved-caspase 3 expression levels, while also reducing the ratio of Bax/Bcl-2. Furthermore, SAA prevented the loss of △Ψm and inhibited the activation of m PTP. Western blotting experiments further revealed that SAA significantly increased the expression of p-Akt and p-GSK-3β, and the increase in p-GSK-3β expression was attenuated after inhibition of the Akt signaling pathway with LY294002. Conclusion: SAA has a protective effect on cardiomyocyte H/R injury; the underlying mechanism may be related to the preservation of mitochondrial function and the activation of the Akt/GSK-3β signaling pathway.

New C_(21)steroidal glycosides from the roots of Cynanchum stauntonii and their protective effects on hypoxia/reoxygenation induced cardiomyocyte injury

Phytochemical investigations from the roots of Cynanchum stauntonii led to obtain four new C_（21） steroidal glycosides（1–4） and one known compound stauntoside F（5）. Their chemical structures were characterized by sophisticated analyses of IR, HRESI-TOF-MS, 1D, and 2D-NMR data, together with chemical methods, which showed interesting 13,14：14,15-disecopregnane-type skeleton or 14,15-secopregnane-type skeleton C_（21） steroidal glycosides. Among them, compound 1 was determined to be glaucogenin C 3-O-b-D-glucopyranosyl-（1 → 4）-b-D-cymaropyranosyl-（1 → 4）-b-D-digitoxopyranosyl-（1 → 4）-b-D-thevetopyranoside. Compound 2 was characterized to be hirundigenin 3-O-a-L-diginopyranosyl-（1 → 4）-b-D-cymaropyranosyl-（1 → 4）-b-D-digitoxopyranosyl-（1 → 4）-b-D-30-demethyl-thevetopyranoside. Compound 3 was identified to be（14S,16 S,20R）-14,16-14,20-15,20-triepoxy-14,15-secopregn-5-en-3-ol-3-O-a-L-cymaropyranosyl-（1 → 4）-b-D-digitoxopyranosyl-（1 → 4）-b-D-oleandropyranoside.Compound 4 was identified to be（14S,16 S,20R）-14,16-14,20-15,20-triepoxy-14,15-secopregn-5-en-3-ol-3-O-a-L-cymaropyranosyl-（1 → 4）-b-D-cymaropyranosyl-（1 → 4）-b-D-digitoxopyranosyl-（1 → 4）-b-Dthevetopyranoside. Among them, compound 2 was hirundigenin type C21 steroidal glycoside that existed in nature as epimers due to the presence of 14-hemiketal hydroxyl group in its structure. In addition, the anti-inflammatory and cardiomyocyte protective effects of compounds 1–4 were evaluated. We found that they exhibited significant protective effects on hypoxia/reoxygenation induced cardiomyocyte injury, but did not showed obvious anti-inflammatory function.

Relation or Influence of RVOTO in the Inflammatory Response to Reoxygenation in Patients with Tetralogy of Fallot

Background:This study evaluated differential inflammatory response to cardiopulmonary bypass reoxygenation in tetralogy of Fallot repair.Methods:We performed a retrospective study at a cardiovascular center from 2012 to 2018,including 500 patients aged 1 week–18 years who received complete repair of tetralogy of Fallot.Patients were grouped according to tertiles of preoperative RVOT gradient on echocardiography into mild,moderate,and severe stenosis.We measured the highest perfusate oxygenation(PpO_(2))during aortic occlusion as independent variable.Primary outcome was systemic inflammatory response syndrome(SIRS)within 7 days postoperatively or the time of death or discharge.Results:Overall,rate of SIRS was 24.2% without significant differences among three groups(P>0.05).Older age,male,and smaller indexed left ventricular end-diastolic volume is independent risk factor of SIRS.There were significant interactions between RVOT stenosis and PpO2 on SIRS(P interaction=0.011):higher PpO_(2) was associated with a greater SIRS risk among combined moderate and severe stenotic children(OR 1.46395%CI[1.080,1.981]per-SD increase,P=0.014)but not among mild stenotic children(OR 0.900[0.608,1.333]per-SD increase;P=0.600),independent of covariates.Conclusion:The association of PpO_(2) with SIRS was modified by RVOT obstruction severity in tetralogy of Fallot repair.

利多卡因通过降低微小RNA-181a表达抑制缺氧/复氧诱导的心肌细胞损伤

目的 探讨利多卡因通过调控微小RNA-181a(miR-181a)对缺氧/复氧(H/R)诱导的心肌细胞H9C2损伤的影响。方法 培养H9C2细胞,建立H/R模型,作为H/R组;正常培养的细胞作为对照(Con)组。使用1.0、2.5、5.0、10.0、20.0μmol/L利多卡因处理H/R诱导的H9C2细胞,并分别设为1.0μmol/L组、2.5μmol/L组、5.0μmol/L组、10.0μmol/L组和20.0μmol/L组。将anti-miR-NC、anti-miR-181a分别转染至H/R诱导的H9C2细胞,记为H/R+anti-miR-NC组、H/R+anti-miR-181a组。将miR-NC、miR-181a分别转染至H/R诱导的H9C2细胞,再用20.0μmol/L利多卡因处理,分别记为H/R+miR-NC+20.0μmol/L组、H/R+miR-181a+20.0μmol/L组。采用MTT实验检测细胞活性;采用流式细胞术检测细胞凋亡;采用蛋白质印迹(Western blot)检测细胞半胱氨酸天冬氨酸蛋白酶-3(Caspase-3)蛋白表达;采用实时荧光定量聚合酶链反应(RT-qPCR)检测miR-181a表达;检测丙二醛(MDA)含量及乳酸脱氢酶(LDH)、超氧化物歧化酶(SOD)活性;采用酶联免疫吸附实验(ELISA)检测炎性因子[肿瘤坏死因子-α(TNF-α)、白细胞介素-1β(IL-1β)、白细胞介素-6(IL-6)]的水平。结果 与Con组相比,H/R组细胞活性降低,差异有统计学意义(P<0.05)。与H/R组相比,5.0μmol/L组、10.0μmol/L组和20.0μmol/L组的细胞活性提高,差异有统计学意义(P<0.05)。因此,后续以20.0μmol/L利多卡因进行实验。与Con组相比,H/R组细胞凋亡率、Caspase-3蛋白表达升高,差异有统计学意义(P<0.05)。与H/R组相比,20.0μmol/L组细胞凋亡率、Caspase-3蛋白表达降低,差异有统计学意义(P<0.05)。与Con组相比,H/R组MDA含量、LDH活性以及炎症因子水平提高,SOD活性降低,差异有统计学意义(P<0.05);与H/R组相比,20.0μmol/L组MDA含量、LDH活性以及炎性因子水平降低,SOD活性提高,差异有统计学意义(P<0.05)。与H/R+anti-miR-NC组相比,H/R+anti-miR-181a组细胞miR-181a表达、凋亡率和Caspase-3蛋白表达降低,差异有统计学意义(P<0.05)。与H/R+anti-miR-NC组相比,H/R+anti-miR-181a组MDA含量、LDH活性以及炎性因子水平降低,SOD活性升高,差异有统计学意义(P<0.05)。与H/R+miR-NC+20.0μmol/L组相比,H/R+miR-181a+20.0μmol/L组细胞凋亡率、Caspase-3蛋白和MDA含量、LDH活性以及炎性因子水平升高,SOD活性降低,差异有统计学意义(P<0.05)。结论 利多卡因通过干扰miR-181a表达,抑制H/R诱导的心肌细胞H9C2损伤。

三叶青黄酮通过TLR4/NF-κB通路调控NLRP3小体激活改善大鼠心肌细胞缺氧再复氧损伤的作用及机制

目的探究三叶青黄酮(RTHF)对大鼠心肌细胞缺氧再复氧(H/R)损伤的作用及其可能机制。方法以大鼠心肌细胞H9C2为研究对象,分为对照组、H/R组、H/R+低浓度RTHF(L-RTHF)组(25μg/mL)、H/R+中浓度RTHF(M-RTHF)组(50μg/mL)和H/R+高浓度RTHF(H-RTHF)组(100μg/mL)。通过CCK-8法检测各组细胞活力;试剂盒检测各组细胞上清液中乳酸脱氢酶(LDH)和超氧化物歧化酶(SOD)含量;DCFH-DA探针法检测细胞内活性氧(ROS)水平;实时荧光定量聚合酶链反应(qRT-PCR)和Western blot检测各组细胞中NOD样受体热蛋白结构域相关蛋白3(NLRP3)、半胱氨酸蛋白酶-1(Caspase-1)、凋亡相关斑点样蛋白(ASC)、消皮素D的N端切割产物(GSDMD-N)、Toll样受体4(TLR4)、磷酸化核因子κB p65(p-NF-κB p65)、核因子κB p65(NF-κB p65)的表达水平。结果与对照组比较,H/R组H9C2细胞活力[(71.33±1.70)%比(100.00±2.94)%,P<0.01]、SOD水平[(15.54±0.36)U/mg prot比(34.54±0.87)U/mg prot,P<0.01]降低,ROS相对DCF强度[(3.72±0.12)比(1.00±0.10),P<0.01]和LDH水平[(387.57±9.37)U/L比(182.80±11.53)U/L,P<0.01]升高,NLRP3[(2.75±0.04)比(1.00±0.02)、(4.71±0.18)比(1.00±0.11),P<0.01]、Caspase-1[(3.02±0.11)比(1.00±0.06)、(3.33±0.09)比(1.00±0.12),P<0.01]、ASC[(3.32±0.12)比(1.00±0.09)、(5.30±0.15)比(1.00±0.10),P<0.01]、GSDMD-N[(3.69±0.14)比(1.00±0.13)、(3.23±0.08)比(1.00±0.06),P<0.01]、TLR4[(4.00±0.12)比(1.00±0.09)、(5.68±0.20)比(1.00±0.10),P<0.01]、p-NF-κB p65[(6.81±0.16)比(1.00±0.10)、(3.25±0.07)比(1.00±0.05),P<0.01]相对mRNA和蛋白水平升高;与H/R组比较,H/R+M-RTHF组和H/R+H-RTHF组的细胞活力[(77.00±2.16)%、(82.00±2.16)%比(71.33±1.70)%,P<0.05或P<0.01]、SOD水平[(23.43±1.50)U/mg prot、(28.66±1.22)U/mg prot比(15.54±0.36)U/mg prot,P<0.05或P<0.01]升高,ROS[(3.24±0.05)、(2.57±0.04)比(3.72±0.12),P<0.05或P<0.01]、LDH[(332.77±5.76)U/L、(253.36±9.43)U/L比(387.57±9.37)U/L,P<0.05或P<0.01]水平降低,NLRP3[(1.86±0.06)、(1.56±0.09)比(2.75±0.04),(2.97±0.11)、(1.86±0.06)比(4.71±0.18),P<0.05或P<0.01]、Caspase-1[(2.06±0.13)、(1.27±0.06)比(3.02±0.11),(2.12±0.15)、(1.42±0.09)比(3.33±0.09),P<0.05或P<0.01]、ASC[(2.40±0.25)、(2.19±0.14)比(3.32±0.12),(2.46±0.08)、(1.28±0.05)比(5.30±0.15),P<0.05或P<0.01]、GSDMD-N[(2.43±0.07)、(2.19±0.13)比(3.69±0.14),(1.91±0.07)、(1.46±0.07)比(3.23±0.08),P<0.05或P<0.01]、TLR4[(3.52±0.09)、(1.88±0.11)比(4.00±0.12),(4.04±0.32)、(2.07±0.07)比(5.68±0.20),P<0.05或P<0.01]、p-NF-κB p65[(4.09±0.12)、(3.03±0.20)比(6.81±0.16),(1.93±0.31)、(1.39±0.12)比(3.25±0.07),P<0.05或P<0.01]相对mRNA和蛋白水平降低,且这种变化呈现RTHF剂量依赖性。结论在H/R诱导的大鼠心肌细胞中,RTHF可能通过抑制ROS和TLR4/NF-κB通路调控NLRP3小体激活,进而抑制细胞焦亡。

缺氧后处理通过piRNA-005854调控衰老心肌细胞自噬发挥保护心肌作用

背景:缺血后处理是减轻缺血再灌注损伤的有效方式之一,近年来被越来越广泛地应用于临床实践,但其具体分子机制还有待研究。目的:探讨piRNA-005854在衰老心肌细胞缺氧后处理中的作用及机制。方法:体外给予心肌细胞8 mg/mL D-半乳糖9 d诱导其衰老,β-半乳糖苷酶染色观察心肌细胞的衰老情况;衰老后细胞给予缺氧/复氧处理和缺氧后处理,ELISA检测心肌损伤标志物肌酸激酶同工酶MB以及乳酸脱氢酶水平;Western blot检测衰老心肌细胞中自噬相关蛋白LC3Ⅱ、p62和ULK1及其磷酸化ULK1的表达;qRT-PCR检测piRNA-005854的表达水平;进一步用piRNA-005854 inhibitor及piRNA-005854 mimics转染衰老心肌细胞并进行缺氧后处理,Western blot检测LC3Ⅱ、p62和ULK1及其磷酸化ULK1的表达。结果与结论:①D-半乳糖诱导9 d后心肌细胞出现明显衰老;②与正常氧组比较,缺氧/复氧组肌酸激酶同工酶MB以及乳酸脱氢酶水平增加(P<0.01);LC3Ⅱ/Ⅰ表达升高、p62表达降低、ULK1磷酸化水平升高、piRNA-005854表达升高(P<0.01);③与缺氧/复氧组比较,缺氧后处理组肌酸激酶同工酶MB以及乳酸脱氢酶水平明显减少(P<0.01);LC3Ⅱ/Ⅰ表达明显降低(P<0.05)、p62表达升高(P<0.01)、ULK1磷酸化水平降低(P<0.05)、piRNA-005854表达降低(P<0.01);④转染piRNA-005854 inhibitor后,LC3Ⅱ/Ⅰ表达降低(P<0.01),p62表达明显升高(P<0.05),ULK1磷酸化水平明显降低(P<0.01);转染piRNA-005854 mimics后,LC3Ⅱ/Ⅰ表达显著升高,p62表达降低,ULK1磷酸化水平明显增加(P<0.01);⑤结果表明,piRNA-005854介导的ULK1依赖性自噬水平降低是衰老心肌细胞缺氧后处理发挥保护作用的可能机制。

虾青素通过调控氧化应激和炎症反应修复压力性损伤

目的探究虾青素对小鼠压力性损伤创面的修复作用。方法体外实验:用不同浓度虾青素处理成纤维细胞,通过CCK-8实验检测细胞的增殖活性。随后通过缺氧/复氧诱导成纤维细胞损伤,给予最适浓度虾青素,用DHE荧光探针检测细胞内活性氧水平,RT-qPCR检测细胞内TNF-α、IL-1β、IL-6、IL-10、TGF-β的mRNA表达。体内实验:将两块圆形磁铁对称吸附于小鼠皮肤两侧,5 h后移除磁铁,以构建压力性损伤模型。随后分组灌胃等量的生理盐水、低剂量虾青素(10 mg/kg)与高剂量虾青素(20 mg/kg),定期采集创面图像。治疗7 d后,统计创面愈合率,并采集创面组织进行组织病理学染色。结果体外:应用虾青素后,缺氧/复氧损伤成纤维细胞内DHE荧光强度显著降低,TNF-α、IL-1β、IL-6 mRNA表达水平明显下调,TGF-β、IL-10 mRNA表达显著上调(P<0.05)。体内:高剂量虾青素组创面愈合率显著提高,DHE荧光强度显著降低,创面组织TNF-α、IL-6明显减少,TGF-β、IL-10明显增多(P<0.05)。结论虾青素可显著改善氧化应激,减轻炎症反应,对压力性损伤创面具有保护作用。

虫草素调控受体相互作用蛋白激酶1介导的凋亡改善缺氧/复氧诱导的人肾小管上皮细胞损伤

目的基于基因表达综合(gene expression omnibus,GEO)数据库中的基因芯片、网络药理学、分子对接和体外实验探讨虫草素治疗急性肾损伤(acute kidney injury,AKI)的作用机制。方法从GEO(GSE87025)、GeneCards 2个数据库获得AKI的疾病靶点。从TargetNet、BATMAN和GeneCards 3个数据库获得虫草素相关靶点。对AKI和虫草素相关靶点取并集,筛选出共同靶基因。进行基因本体论(gene ontology,GO)注释和京都基因与基因组百科全书(kyoto encyclopedia of genes and genomes,KEGG)通路富集分析后对虫草素及关键靶点进行分子对接。细胞实验设计对照组、缺氧/复氧组、缺氧/复氧+虫草素组对相关靶点进行实验验证。结果AKI和虫草素共同靶基因共12个,GO功能注释结果表明主要参与凋亡信号通路的负调控、坏死性凋亡过程等生物学过程,KEGG富集分析结果表明主要参与Toll样受体信号通路、坏死性凋亡、核苷酸结合寡聚化结构域(nucleotide-binding oligomerization domain,NOD)样受体信号通路、核因子κB(nuclear factor-κB,NF-κB)信号通路、肿瘤坏死因子(tumor necrosis factor,TNF)信号通路和细胞凋亡等常见信号通路。虫草素和受体相互作用蛋白激酶1(receptor-interacting protein kinase 1,RIPK1)分子对接的最优结合能为-7.1,表明两者有较强的结合活性。蛋白免疫印迹结果表明虫草素可下调RIPK1、Bcl-2相关X蛋白、凋亡指标胱天蛋白酶表达、上调B细胞淋巴瘤/白血病-2的表达,细胞免疫荧光结果表明虫草素可下调RIPK1表达。结论虫草素可通过调控RIPK1介导的凋亡缓解缺氧/复氧诱导的人肾小管上皮细胞损伤,以达到治疗AKI的效果。

丹酚酸B通过调控AMPK介导的铁死亡保护缺氧/复氧诱导的肾小管上皮细胞的损伤

目的:探究丹酚酸B(Salvianolic acid B,Sal B)对于缺氧/复氧(hypoxia/reoxygenation,H/R)所致肾小管上皮细胞损伤的保护作用及其机制。方法:体外实验细胞分组为正常对照(Con)组,Sal B+Con组、H/R组、Sal B+H/R组,以及Con组、H/R组、Sal B+H/R组、H/R+CC(Compound c,AMPK抑制剂)组、H/R+Sal B+CC组两部分。体外实验用CCK‑8法检测HK‑2细胞活性;细胞震碎,取上清,用酶标仪检测GSH和MDA的含量;Western blot检测p‑AMPK、GPX4、ACSL4和FSP1蛋白的表达情况;细胞免疫荧光检测铁死亡指标GPX4、ACSL4蛋白的表达情况;流式细胞术检测线粒体膜电位和细胞凋亡。结果:体外实验结果显示,Sal B在20~160μmol/L对正常HK‑2细胞活性无明显毒性(P>0.05);与模型组相比,20、40、80μmol/L的Sal B呈剂量依赖性提高HK‑2细胞的活性(P<0.01)。与模型组相比,H/R+Sal B组细胞MDA含量降低,GSH含量升高,p‑AMPK、GPX4和FSP1蛋白的表达水平升高,ACSL4蛋白的表达降低,细胞线粒体膜电位显著升高,细胞凋亡率显著下降(P<0.05);H/R+AMPK组较H/R+Sal B组FSP1和GPX4蛋白表达水平降低,ACSL4蛋白的表达水平升高(P<0.05),细胞线粒体膜电位显著降低(P<0.05),加入Sal B可以逆转这一情况(P<0.05)。结论:Sal B可减轻H/R的肾小管上皮细胞的损伤,其机制可能与激活AMPK通路减轻肾小管上皮细胞铁死亡有关。