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Hypoxic preconditioning could improve the survival of mesenchymal stem cells (MSCs) in ischemic or hypoxic environments, but its exact mechanism remains to be further explored. This study aims to determine the role of lysine crotonylation (Kcr) in regulating the survival and proliferation of peripheral blood mesenchymal stem cells (PBMSCs) in the hypoxic culture. PBMSCs were isolated and cultured from rat peripheral blood mononuclear cells, and their surface markers were identified by flow cytometry. PBMSCs were first subjected to hypoxic/ normoxic preconditioning: hypoxic (1% O
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Objective To investigate the effect of hypoxic pretreatment on the angiogenesis of aged human bone marrow mesenchymal stem cells (hBMSCs), so to provide experimental support for more effective autologous stem cell transplantation therapy in aged patients with ischemic myocardial injury. Methods The aged hBMSCs were cultured in a hypoxic incubator, and then the cell morphology was observed under inverted phase-contrast microscope, the surface markers were detected by flow cytometry, and the differentiation potential was detected by osteogenic and adipogenic differentiation. Subsequently, the conditioned medium (CM) of young hBMSCs under normoxic culture (norCM), the conditioned media of aged hBMSCs under normoxic and hypoxic culture(hypoCM) were collected respectively. They were named as norCM-young, norCM-old and hypoCM-old. The equal volume of medium, which was not treated with stem cells, was set as control group. Human umbilical vein endothelial cells (HUVECs) were treated with 4 conditioned media, the cell survival rate was detected by CCK-8 assay, and the tube formation experiment was used to detect the angiogenesis ability in vitro. The BCA method was used to detect the total protein concentration of the conditioned medium of each group, and the Western blotting was used to detect the expression of hypoxia inducible factor-1α (HIF-1α) in the cells and the conditioned media. Results There was not significant effect of hypoxic pretreatment on the morphology, surface markers and differentiation ability of aged hBMSCs (P > 0. 05. n ≥ 3). Compared with the norCM-old group, hypoCM-old group significantly improved the survival of HUVECs under hypoxia-reoxygenation condition (P < 0. 05, n = 5), and the tube formation ability of it (P<0. 01, n = 5). The total protein concentration of hypoCM-old group was significantly higher than that of norCM-old group (P<0. 05, n = 3). The expression of HIF-1α in hBMSCs of hypo-old group was significantly higher than that of nor-old group (P<0. 05,n = 3), while the content of HIF-1α in conditioned medium of hypoCM-old group was significantly higher than that in norCM-old group (P<0. 01,n = 3). Conclusion The aged hBMSCs pretreated with hypoxia can promote the survival and tube formation of HUVECs through paracrine in vitro, which is HIF-1α-related.
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[Abstract] Objective To investigate the protective effects of hypoxic preconditioning (HPC) on cardiomyocytes after hypoxia/reoxygenation (H/R) by activating AMP-activated protein kinase (AMPK). Methods The primary cardiomyocytes were prepared from neonatal SD rats. The model of H/R of cardiomyocytes was established and randomly divided into control group, H/R group, HPC group, H/R+A-769662 (AMPK agonist) group and HPC+compound C (AMPK inhibitor) group. The survival rate of cardiomyocytes was detected by chromatometry with Cell Counting Kit-8 (CCK-8); the reactive oxygen species (ROS) and ATP contents in the cells were detected respectively by dihydroethidium (DHE) dyeing and ATP Detection Assay Kit measured by fluorescence microplate reader; the phosphorylation level of AMPK and activation level of caspase-3 were detected by Western blotting; the concentration of free Ca2+ in cardiomyocytes was detected by Fluo-3AM dyeing using laser scanning confocal microscopy; the apoptotic rate of cardiomyocytes was detected by TUNEL staining. Results CCK-8 assay showed that compared with H/R group, the survival rate of cardiomyocytes in HPC group and H/R+A-769662 group increased obviously (P0.05); compared with H/ R group, the AMPK phosphorylation levels elevated significantly in HPC group and H/R+A-769662 group respectively (P<0.05, P<0.01). Meanwhile, the activation levels of caspase-3 in H/R group and HPC+compound C group were increased obviously compared with that in control group (P<0.01), but in HPC group and H/R+A-769662 group were significantly lower than that in H/R group (P<0.01, P<0.05). The results of Fluo-3AM staining showed that compared with control group, the concentrations of intracellular free Ca2+ increased obviously in H/R group and HPC+compound C group (P<0.01); the concentrations of free Ca2+ in cardiomyocytes of HPC group and H/R+A-769662 group were less than that in H/R group (P<0.01), while the concentrations of free Ca2+ in HPC+compound C group much more increased than in HPC group (P<0.01). The results of TUNEL staining showed that compared with H/R group, the apoptotic rate of cardiomyocytes decreased obviously in HPC group and H/R+A-769662 group (P<0.01, P<0.05); while compared with HPC group, the apoptotic rate of cardiomyocytes increased significantly in HPC+compound C group (P<0.05). Conclusions H/R may lead to the increase of ROS production, the decrease of ATP contents, and increase the levels of free Ca2+ in cardiomyocytes, and thus activate caspase-3, lead to apoptosis eventually. While HPC may reduce the production of ROS by activating AMPK to ensure the energy supply of cardiomyocytes after H/R treatment, prevent apoptosis of cardiomyocytes, and then reduce the H/R injury to cardiomyocytes.
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Objective To investigate the effects of hypoxic preconditioning on learning and memory and the possible protective mechanism in mice with cerebral ischemia-reperfusion injury.Methods Healthy adult male Kunming mice were randomly divided into five groups by Random number table:normal group( N group),hypoxic preconditioning group (HPC group),sham operation group (C group),ischemia-reperfusion group(O group),hypoxic preconditioning and ischemia-reperfusion group(HPC+O group).HPC+O group were given hypoxic preconditioning before 24h of ischemia-reperfusion.The escape latency was detected by Morris water maze and the neuron apoptosis of CA 1 area of hippocampal was determined by immunofluores-cence techniqueR.e sults The escape latency in HPC+O group on the second,third and fourth day of MWM was (39.92±4.52)s,(30.98±2.44)s,(19.69±4.27)s,and significantly lower than that in O group((54.35± 3.66)s,(46.31±4.81)s,(36.81±3.86)s).Mice in HPC+O spent longer time in the target quadrant than that in O group((36.44±5.33)%and(24.5±2.59)%,respectively, P<0.05).Immunofluorescence showed that the apoptotic ration of nerve cells in hippocampal CA 1 was significantly lower than that in O group ( 11.7 ± 0.14 and 1.35±0.14, P<0.05).Conclusion Hypoxic preconditioning can increase hippocampal CA1 neurons hypoxia tolerance of ischemia reperfusion injury in mice,and reduce the incidence of neural cell apoptosis.
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AIM: To examined the effects of hypoxic preconditioning ( HPC) on oxygen-glucose deprivation ( OGD)-induced PC12 cells, and to investigate its possible mechanisms of autophagy .METHODS: Cultured PC12 cells were randomly divided into control group , HPC group, 3-methyladenine (3-MA) group, HPC+OGD group, 3-MA+HPC+OGD group and OGD group .CCK-8 assay was used to detect the cell viability .The caspase-3 activity was also tested . TUNEL staining and flow cytometry were used to detect the cell apoptosis .The protein levels of apoptosis-related protein caspase-3 and autophagy-marked protein LC3-2 and beclin-1 were determined by Western blot .RESULTS:Compared with control group, the viability of PC12 cells was significantly reduced , and the activity of caspase-3 was significantly increased in OGD group.Compared with 3-MA+HPC+OGD group and OGD group , the viability of PC12 cells was significantly in-creased, and the activity of caspase-3 was significantly reduced in HPC +OGD group (P<0.05).The PC12 cell injury was apparent after OGD with a great increase in the apoptotic rate (P<0.05).Compared with OGD group, the apoptotic rate significantly decreased in HPC +OGD group ( P<0.05 ) .Compared with control group , the protein level of cleaved caspase-3 was significantly increased in OGD group ( P<0.05) .Compared with OGD group , the protein level of cleaved caspase-3 was significantly decreased , and the levels of LC3-2 and beclin-1 were significantly increased in HPC +OGD group (P<0.05).CONCLUSION:OGD decreases cell survival and induces apoptosis .Activation of cell autophagy may be the mechanism by which hypoxic preconditioning protects the PC 12 cells from OGD induced injury .
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Objective To explore the impact and significance of hypoxia preconditioning on the expression of cytochrome C and caspase 3 protein in rats after hepatic resection.Methods A hepatectomy model was used to study the ischemia reperfusion injury in hepatic resection.Sprague-Dawley rats were randomly divided into the following three groups:normal control (NC) group,hepatic resection(HR) group,and hypoxia preconditioning (HP) group,there were twenty four rats in each group.HP Group was given an 10％ oxygen-mixed gas for 90 minutes before the operation.At 1,6,12 and 24 hours after the operation,the rats were killed and the following tests were conducted:(1) Liver tissue was sampled to observe the expression of cytochrome C and caspase 3 protein; (2) blood was drawn to conduct a chemical examination; (3) Liver tissue and morphology was observed by transmission electron microscopy.Results The serum levels of ALT and AST in HP group were significantly lower than that of HR group (P＜0.05) at 1,6,12 and 24 hours after the hepatic resection.In each time,liver function of the HP group was significantly better than the HR group; The expression of cytochrome C and caspase 3 protein was decreased significantly in HP group at each measurement point.Hepatic cells in HR group showed typical apoptosis signs under transmission electron microscopy (TEM),but no apoptosis was found in HP group.Conclusion HP has marked inhibition to apoptosis by down-regulating the expression of Cyt C and Caspase-3protein and protection to chondrosomes after a hepatic resection.
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Objective To investigate the effects of intermittent hypoxic preconditioning on residual liver regeneration after parital hepatectomy in rats.Methods Fifty-four Sprague-Dawley rats were randomly divided into 3 groups (each group contained eighteen animals):sham operation group (SO group),parital hepatectomy group (PH group)and intermittent hypoxic preconditioning group (IHP group).The rats in PH group underwent the left and middle lobectomy of liver(70％ hepatectomy).The rats in IHP group were exposed to hypoxic environment of 10％ oxygen for 1 h/d.And after a week,the rats underwent parital hepatectomy.Six rats in each group were sacrificed respectively on postoperative day 1,3 and 5 (POD 1,3 and 5).The resected liver and the regenerated liver were weighed to calculate liver regeneration degree and regeneration index.The values of alaninea minotransferase (ALT) and aspartate aminotransferase (AST) in the inferior vena venous blood were examined by automatic biochemical analyzer.The positive ratio of hepatocellular proliferating cell nuclear antigen (PCNA) in the residual liver was investigated immunohistochemically.Results The degree and index of liver regeneration in IHP group were respectively higher than those in PH group on POD 1 and 3(P ＜0.05),but there were no statistical differences between the two groups on POD 5.The levels of ALT and AST in PH and IHP group began to decline after surgery,but they remined higher than those in SO group.Moreover,the ALT and AST levels in IHP group were significantly lower than those in PH group on POD 1 (P ＜0.05).The positive ratios of hepatocellular PCNA were respectively higher than those in SO and PH group on POD 1,3 and 5 (P ＜ 0.05).Conclusions To some extent,preoperative intermittent hypoxic preconditioning could prevent hepatocellular damage after parital hepatectomy,what is more,it also could promote the remnant liver regeneration.But the mechanism still needs to be studied furter.
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AIM:To elucidate whether ZFP580 is involved in the cardioprotective effects of hypoxic precondi-tioning (HPC) against hypoxia-reoxygenation (H/R) injury in H9c2 myocardial cells.METHODS: Rat heart-derived H9c2 cells were cultured in DMEM .H/R was induced by incubation under ischemic hypoxia for 3 h and reoxygenation for 2 h.HPC was induced by exposing the H 9c2 cells to 10 min of hypoxia and 20 min of reoxygenation for 3 cycles before H/R treatment.MTT staining and LDH leakage detection were used to evaluate the effects of HPC .Western blotting was used to detect the protein levels of ZFP580, phosphorylated ERK1/2 and cleaved caspased-3.The effects of ZFP580 overexpre-ssion or knockdown on H/R induced apoptosis were determined .RESULTS:The results of MTT staining and LDH leakage detection showed evidence of HPC cytoprotection against H /R-induced cell death in H9c2 cells.ZFP580 protein level and ERK1/2 phosphorylation were significantly increased in the HPC group compared with control group and H /R group. PD98059, an inhibitor of ERK1/2 phosphorylation , significantly suppressed the HPC-induced up-regulation of ZFP580 pro-tein expression.ZFP580 overexpression significantly inhibited apoptosis and caspase-3 activation in H9c2 cells.CON-CLUSION:HPC exhibits cytoprotection against H/R and leads to high level of ZFP 580 protein in H9c2 cells.ZFP580 is regulated by ERK1/2 activation and mediates the anti-apoptotic effect of the ERK1/2 signaling pathway in HPC cytoprotec-tion.
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INTRODUCCION: El estrés oxidativo (EO) es importante en la génesis de diversas patologías. Su rol en patología cardiovascular es reconocido, particularmente en isquemia-reperfusión, fenómeno asociado al uso de circulación extracorpórea (CEC) en cardiocirugía. Complicación frecuente es la fibrilación auricular post-operatoria(FAPO), que ha demostrado participación del EO. Estrategias que lo atenúen podrían reducir incidencia de FAPO. Este trabajo busca determinar efectos de un esquema de suplementación para prevenir el EO y FAPO. METODOLOGIA: Ensayo clínico, doble ciego, aleatorizado. A 80 pacientes programados para cardiocirugía con CEC se administró placebo (n=40) o suplementación(n=40), consistiendo desde 7 días antes de la cirugía ácidos grasos poli-insaturados omega-3 (n-3) (2 g/día), y 2 días pre-cirugía se agrega vitamina C (1 g/día) y E (400 UI/día), todo hasta el alta. Se obtuvieron muestras sanguíneas (al ingreso, en suplementación, en cirugía, en postoperatorio y al alta) y auriculares durante cirugía. El estado antioxidante fue medido por la habilidad plasmática para reducir hierro férrico (FRAP) y el índice GSH/GSSG. Se midió actividad de enzimas catalasa, superóxido-dismutasa y glutatión-peroxidasa. Lipoperoxidación fue medida por niveles de malondialdehído. Para variables paramétricas se usó t de student, entre grupos se usó ANOVA-Bonferroni. Significancia fue p<0.05. RESULTADOS: Suplementación con n-3 disminuyó índice GSH/GSSG en 25 por ciento. En postoperatorio hubo 21 por ciento menos de lipoperoxidación y niveles de FRAP 30 por ciento mayores. Actividad de enzimas mostró incremento significativo. Además disminuyó FAPO desde 25 por ciento a 7,5 por ciento. CONCLUSION: Suplementar con n-3 y vitaminas antioxidantes disminuye ocurrencia de FAPO evitando daño miocárdico bioquímico y funcional por EO.
INTRODUCTION: Oxidative stress is important in the genesis of several diseases. Their role in cardiovascular disease is recognized, particularly in ischemia-reperfusion, a phenomenon associated with the use of cardiopulmonary bypass (CPB) in cardiac surgery. Common complication is postoperative atrial fibrillation (FOAP), which has demonstrated participation of oxidative stress, strategies to mitigate what could reduce the occurrence of FOAP. This paper tries to determine the effect of a supplementation scheme to prevent oxidative stress and its consequences. MATERIALS AND METHODS: Randomized, double-blind, controlled trial. Eighty patients scheduled for CCEC received placebo (n = 40) or supplementation (n = 40). Inclusion criteria: Age 30-80 years, sinus rhythm. Exclusion criteria: previous cardiosurgery, paroxysmal atrial fibrillation, congenital heart disease, chronic diseases. The supplementation consisting of n-3 (2 g / day), vitamins C (1 g /day) and E (400 IU / day) from 7, 2 and 2 days before surgery, respectively, until discharge. In atrial tissue and blood samples the plasma ferric reducing ability (FRAP), index GSH/GSSG, activity of catalase, superoxide dismutase and glutathione-peroxidase, and malondialdehyde levels were measured. Protein carbonylationwas measured in atrial tissue. Parametric variables expressed as mean and standard error were analyzed with students t-test, groups were compared using ANOVA-Bonferroni. Significance was p <0.05. RESULTS: The supplementation reduced the incidence of FOAP, lipid peroxidation and protein carbonylation in 73, 21 and 19 percent (p <0.05), respectively, and increased the FRAP (30 percent) and activity of antioxidant enzymes (p <0.05). CONCLUSIONS: Antioxidant supplementation decreases FOAP probably avoiding damage by oxidative stress.
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Humans , Male , Female , Adult , Middle Aged , Aged, 80 and over , /administration & dosage , Antioxidants/administration & dosage , Extracorporeal Circulation , Atrial Fibrillation/prevention & control , Ischemic Preconditioning, Myocardial/methods , Cardiac Surgical Procedures/adverse effects , Analysis of Variance , Ascorbic Acid/administration & dosage , Double-Blind Method , Atrial Fibrillation/etiology , Lipid Peroxidation , Oxidative Stress , Protein Carbonylation , Time Factors , Vitamin E/administration & dosageABSTRACT
Objective To explore the effect of hypoxic preconditioning on the activity and gene expressions of glu-cose transporters in the cultured rat hippocampal neurons and astrocytes under anoxic condition. Methods The cultured rat hippocampal neurons and astrocytes were treated for 6 days by intermittently exposing to hypoxic gas mixture (1% O_2, 10% CO_2, 89% N_2) for20 min each day. 24 h after the last hypoxic exposure, the cells were exposed to anoxic gas mixture (10% CO_2, 90% N_2) for 6 h, and the uptake rate of [~3H]-2-deoxyglucose (2-DG), the levels of glucose transporter GLUT1 and GLUT3 mRNAs and the cell survival rate were examined im-mediately after anoxic exposure. Results Neurons and astrocytes preconditioned with hypoxia showed higher 2-DG uptake rates and increased expressions of GLUT 1 mRNA in the astrocytes and GLUT 1 and GLUT 3 mRNA in the neurons. The preconditioned neurons also showed an increased tolerance to anoxia. Conclusion Hypoxic precon-ditioning up-regulates the activity and gene expressions of glucose transporters of hippocampal neurons and astro-cytes under anoxic condition.
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Objective To investigate whether conventional protein kinase C (cPKC ) βⅡ-interacting collapsin response mediator protein-2 (CRMP-2) provides neuroprotection against cerebral ischemic (I) injuries. Methods Male BALB/c mice were randomly divided into normoxic control (Nor) , HPC, Nor + Sham, HPC + Sham, Nor + I and HPC + I groups (n = 6 per group). Using our HPC and MCAO mouse models, we applied immunoprecipita-tion, two-dimensional electrophoresis and mass spectrometry to characterize cPKCβⅡ-interacting proteins and combined with SDS-PAGE and Western blot to quantitatively analyze CRMP-2 phosphorylation and degradation levels in the brain of mice after HPC and MCAO. Results The expression level of 10 cPKCβⅡ-interacting proteins changed obviously in cerebral cortex of HPC mice when compared with Nor group. One of these proteins, CRMP-2 protein level increased in particulate fraction and decreased in cytosolic fraction of cerebral cortex of HPC mice. CRMP-2 phosphorylation level in ischemic core (Ic) of cerebral cortex decreased significantly ( P < 0. 05 , n = 6) as compared with that of Nor + sham group, but CRMP-2 phosphorylation level in HPC +I group increased significantly as compared with that of Nor +I group ( P < 0. 05, n = 6). In ischemic cortex, CRMP-2 degradation (proteolysis) was observed as the appearance of 55 ku breakdown products (BDP). However, the CRMP-2 degradation level, BDPs products decreased significantly in penumbra ( P) of ischemic cortex from HPC +I group when we compared with that of Nor +I group (P < 0. 05, n = 6 ). Conclusion CRMP-2 is involved in attenuating the decrease of CRMP-2 phosphorylation in ischemic core and in inhibiting its degradation in penumbra of cerebral cortex of mice thereby to lessen the ischemic injuries.
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0.05).Conclusions HPC has protective effect on neonatal rats with cerebral hypoxia-ischemia,but it does not have obvious effect on NGB.
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Objective To observe the protective effects of hypoxic preconditioning(HPC) on the improvement of the cognitive dysfunction(learning and memory) and the damage in hippocampus induced by global cerebral ischemia/reperfusion(I/R) in CA1 and CA3 for 5 days in rats,and on the regulation of expression of erythropoietin(EPO) protein to approach the mechanism of the protection.Methods One hundred and twenty adult male Sprague-Dawley(SD) rats were divided into four groups randomly: sham group,I/R group,HPC24 group(hypoxia for 24 hours before I/R) and HPC48 group(hypoxia for 48 hours before I/R).Hang(motor function),passive avoidance and Morris water maze tests were carried out on the 5th day after I/R to measure the motor and cognition functions;hematoxylin-eosin(HE) staining was used to detected histopathological changes in hippocampus tissues;and the contents of EPO were tested by immunohistochemistry at 1 hour and 4 hours after I/R from hippocampus CA1 and CA3 regions.Results Hang,passive avoidance and Morris water maze tests showed that I/R can injure rat cognition;the improvement of cognition was marked in HPC groups, and it was shown that the effects were more significant in HPC48 group than those in the HPC24 group(P
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Objective To determine the changes in phosphorylation of conventional protein kinase C?(cPKC?)-interacting extracellular signal regulated kinase 1/2(ERK1/2) in the hippocampus of hypoxic preconditioned(HPC) mice.Methods Healthy male BalB/c mice were used to develop "auto-hypoxia"-induced HPC mice and randomly divided into 3 groups as follows: normoxic control(H0),early(H3) and delayed hypoxic preconditioned groups(H6).Co-immunoprecipitation and Western blot were applied to quantitatively analyze the phosphorylation level of cPKC?-interacting ERK1/2 in cytosolic and particulate fractions of hippocampus of HPC mice.ResultsERK1/2 was co-immunoprecipitated by cPKC? in hippocampus of mice.The phosphorylation level of cPKC? interacting ERK1/2 at tyrosine 204 decreased significantly in the hippocampus of H3 and H6 groups as compared with that of the H0 group(P
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Objective To explore the role of P38 mitogen-activated protein kinase (P38 MAPK) in the development of cerebral hypoxic preconditioning. Methods Healthy male BALB/C mice weighted as18～20 g were randomly divided into 7 groups as follows: normoxic control (H0), early (H1～H4) and delayed (H5 and H6) hypoxic preconditioned mice groups. SDS-PAGE, Western blot and Gel Doc imagine systems were applied to quantitatively analyze the level of P38 MAPK phosphorylation and protein expression in the brain of mice. Results The phosphorylation levels of P38 MAPK increased in cortex, hippocampus and hypothalamus of mice in both early (H1～H4) and delayed (H5 and H6) hypoxic preconditioned groups, and the statistic significance (P
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Objective To explore the role of conventional protein kinase C(cPKCs) in delayed hypoxic preconditioning.Methods The biochemistry techniques of SDS-PAGE,Western bolt and Gel Doc imagine were applied to analyze the effect of repetitive hypoxic exposure(H5,H6) on the level of cPKC?,? membrane translocation and protein expression in murine brain.Results We found that cPKC? protein expression was significantly decreased(P
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In order to investigate the protective effect of hypoxic preconditioning on the cerebral ischemia-reperfusion injury, the expression of Bcl-2 and Bax was detected by using immunohistochemical staining after 3 h cerebral ischemia followed by 1, 6, 12, 24 and 48 h reperfusion respectively in rats treated with or without hypoxic preconditioning before cerebral ischemia. In addition,the apoptosis of neural cells and the behavioral scores for neurological functions recovery were evaluated by TUNEL staining and "crawvling method", respectively. Compared with control group (cerebral ischemia-reperfusion without hypoxic preconditioning), the expression of Bcl-2 was significantly increased, but that of Bax decreased in the hypoxic preconditioning group (cerebral ischemiareperfusion with hypoxic preconditioning), both P＜0. 05. The pre-treatment with hypoxic preconditioning could reduce the apoptosis of neural cells and promote the neurological function recovery as compared to control group. It was suggested that hypoxic preconditioning may have protective effects on the cerebral ischemia-reperfusion injury by inhibiting the apoptosis of neural cells, increase the expression of Bcl-2 and decrease the expression of Bax.
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BACKGROUND: A brief episode of cerebral ischemia confers transient ischemic tolerance to a subsequent ischemic challenge. We examined the effect of ischemic and hypoxic preconditioning in the neonatal rat. METHODS: Seven-day old Sprague-Dawley rat pups were divided into three groups:control (n = 53), ischemic preconditioning (n = 51), and hypoxic preconditioning (n = 48). For ischemic preconditioning, the right common carotid artery was occluded for 10 min. Rats in the hypoxic preconditioning group were kept under hypoxic (8% oxygen/92% nitrogen) conditions for 4h. Twenty-four hours after the preconditioning, rats from all groups were exposed to the right common carotid artery ligature, followed by 2.5 h of hypoxia. Lipid/N-acetyl aspartate (Lip/NAA) and lipid/creatine (Lip/Cr) ratios from 1H MR spectroscopy and terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end-labeling (TUNEL) were evaluated as measures of apoptosis 1 and 7 days after hypoxic-ischemic injury. RESULTS: In the ischemic and hypoxic preconditioning groups, the Lip/NAA and Lip/Cr ratios and the numbers of TUNEL-positive cells were significantly lower than those in the control group (P < 0.05), but there were no significant differences between the two preconditioning groups. CONCLUSIONS: These results suggest that ischemic and hypoxic preconditioning in the neonatal rat attenuate the apoptosis that is caused by hypoxic-ischemic brain injury.
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Animals , Rats , Hypoxia , Apoptosis , Aspartic Acid , Brain Injuries , Brain Ischemia , Brain , Carotid Artery, Common , Ischemic Preconditioning , Ligation , Magnetic Resonance Spectroscopy , Rats, Sprague-DawleyABSTRACT
Objective To study the effects of hypoxic preconditioning on the Fos and Jun expression and apoptosis in cultured rat hippocampal neurons after anoxia\|reoxygenation. Methods The hippocampal neurons cultured for 12d from control and hypoxic\|preconditioning groups were exposed to anoxia environment (0^90?l/L N\-2+0^10?l/L CO\-2) for 4h and than reoxygenated for 24h and 72h.The expression of Fos and Jun were revealed immunocytochemically using the antiserum against Fos and Jun.The apoptosis was examied using the terminal deoxynucleotidyl transferese\|mediated biotinylated deoxyuridine triphosphate nickel and labeling(TUNEL) method and flow cytometric analysis. Results The increased of percentage of Fos and Jun positive neurons and apoptosis neurons in cultured hippocampal neurons after anoxia\|reoxygenation than those in befor anoxia.The precentage of Fos and Jun positive neurons and apoptosis neurons were less in the hypoxic\|preconditioning group than that in control aftre anoxia\|reoxygenation.Conclusion\ Hypoxic\|preconditioning increases tolerance of hippocampal neurons to anoxia and decreases the precentage in Fos and Jun expressing neurons and apoptosis neurons in hippocampus aftre anoxia\|reoxygenation in vitro. \;[
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AIM:To investigate whether hypoxic preconditioning(HPC)protects cardiomyoblast H9c2 cells against oxidative injury,and to discuss whether calreticulin(CRT)contribute to this protection through p38 MAPK signaling pathway.METHODS:Cardiomyoblast H9c2 cells were randomly divided into eight groups as follows:hydrogen peroxide stress(H2O2);brief hypoxic exposure of 20 min to simulate hypoxic preconditioning(HPC);20 min of hypoxic exposure followed by 24 h of normoxic reoxygenation before hydrogen peroxide stress(HPC+H2O2),SB203580(the specific inhibitors of p38 MAPK)+HPC+H2O2,antisense oligonucleotides transfection of calreticulin(AS),AS+H2O2,AS+HPC+H2O2 and control.Morphological studies,estimation of lactate dehydrogenase(LDH)leakage and flow cytometry were employed to assess the cell apoptosis and necrosis.RT-PCR and Western blotting analysis was used to detect calreticulin expression and phosphorylation of p38 MAPK.RESULTS:The results obtained are as follows:(1)HPC relieved cell injury caused by H2O2.Compared with those in H2O2 group,apoptosis rate and LDH leakage in culture medium in HPC + H2O2 group decreased 13.4% and 44.0%,respectively(P