Propofol Postconditioning Research Articles

Propofol postconditioning alleviates diabetic myocardial ischemia‑reperfusion injury via the miR‑200c‑3p/AdipoR2/STAT3 signaling pathway.

Myocardial ischemia/reperfusion (MI/RI) syndrome is one of the leading causes of mortality and disability. Propofol postconditioning is known to improve myocardial ischemia/reperfusion injury (MI/RI). The present study aimed to explore the mechanism of propofol postconditioning in diabetic MI/RI. Diabetic MI/RI rat models were established and the rats were treated via propofol postconditioning. Staining with 2,3,5-triphenyl-2H-tetrazolium chloride, H&E staining, TUNEL staining and ELISA were applied to detect infarct size, pathological changes, apoptosis and oxidative stress-related factor and apoptotic factor levels, respectively. Subsequently, the effect of propofol on H9C2 cells was also assessed using the Cell Counting Kit-8 assay. High-glucose hypoxia/reperfusion (H/R) models of H9C2 cardiomyocytes were established. miR-200c-3p overexpression or AdipoR2 silencing combined with propofol postconditioning was performed in H/R-induced H9C2 cells and STAT3 protein expression levels were determined. Propofol postconditioning significantly reduced myocardial infarct size, oxidative stress and apoptosis in diabetic MI/RI models. Furthermore, propofol postconditioning significantly reduced the oxidative stress and apoptosis of H9C2 cells in high-glucose H/R models. Propofol postconditioning also significantly downregulated miR-200c-3p expression levels and promoted AdipoR2 expression levels. miR-200c-3p overexpression or AdipoR2 downregulation significantly reversed the effects of propofol postconditioning on its antioxidation and anti-apoptotic effects in H9C2 cells and on decreasing STAT3 phosphorylation levels. Together, the results of the present study demonstrated that propofol postconditioning inhibited miR-200c-3p, upregulated AdipoR2 and activated the STAT3 signaling pathway, thus alleviating diabetic MI/RI and therefore highlighting its potential as a treatment of diabetic MI/RI.

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

BackgroundAdministration 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 injury, while the underlying mechanism remains incompletely understood. The 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.MethodsRat heart-derived H9c2 cells were exposed to high glucose (HG) for 48 h (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.ResultsThe 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) (all 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 (all 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 (all P < 0.05, HG + HR + P25 vs. HG + HR + P25 + siRNA-1 or HG + HR + P25 + siRNA-5).ConclusionIt is concluded that propofol postconditioning attenuated H9c2 cardiac cells apoptosis and autophagy induced by H/R injury through upregulating FoxO1 and FoxO3a under hyperglycemia.

Postconditioning with Sevoflurane or Propofol Alleviates Lipopolysaccharide-Induced Neuroinflammation but Exerts Dissimilar Effects on the NR2B Subunit and Cognition.

Neuroinflammation can cause cognitive deficits, and preexisting neuroinflammation is observed frequently in the clinic after trauma, surgery, and infection. Patients with preexisting neuroinflammation often need further medical treatment under general anesthesia. However, the effects of postconditioning with general anesthetics on preexisting neuroinflammation have not been determined. In this study, adult rats were posttreated with sevoflurane or propofol after intracerebroventricular administration of lipopolysaccharide. The effects of sevoflurane or propofol postconditioning on neuroinflammation-induced recognition memory deficits were detected. Our results found that postconditioning with sevoflurane but not propofol reversed the selective spatial recognition memory impairment induced by neuroinflammation, and these differential effects did not appear to be associated with the similar anti-neuroinflammatory responses of general anesthetics. However, postconditioning with propofol induced a selective long-lasting upregulation of extrasynaptic NR2B-containing N-methyl-D-aspartate receptors in the dorsal hippocampus, which downregulated the cAMP response element-binding signaling pathway and impaired spatial recognition memory. Additionally, the NR2B antagonists memantine and Ro25-6981 reversed this neurotoxicity induced by propofol postconditioning. Taken together, these results indicate that under preexisting neuroinflammation, postconditioning with sevoflurane can provide reliable neuroprotection by attenuating lipopolysaccharide-induced neuroinflammation, apoptosis, and neuronal loss and eventually improving spatial recognition deficits. However, although posttreatment with propofol also has the same anti-neuroinflammatory effects, the neurotoxicity caused by propofol postconditioning following neuroinflammation warrants further consideration.

Propofol Postconditioning Ameliorates Hypoxia/Reoxygenation induced H9c2 Cells Apoptosis and Autophagy via upregulating Forkhead Transcription Factors under Hyperglycemia

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 injury , while the underlying mechanism remains incompletely understood. Also, whether or not P‐PostC can confer cardioprotection in diabetes or under hyperglycemic condition has yet to be explored. The FoxO transcription factors were reported to play critical roles in promoting cardiomyocyte survival during conditions of oxidative stress through induction of antioxidants and cell survival pathways (J Biol Chem. 2011;286(9):7468–78) and was 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. We hypothesized that P‐PostC may attenuate hypoxia/reoxygenation (H/R) injury in cardiac origin H9c2 cells by attenuating apoptosis and autophagy through upregulating FoxO1 and FoxO3a under hyperglycemia. Rat heart‐derived H9c2 cells were exposed to high glucose (HG) for 48 hours, then subjected to H/R (composed of 8 hours of hypoxia followed by 12 hours of reoxygenation) in the absence or presence of postconditioning with various concentrations of propofol at the onset of reoxygenation. Our data 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 25μM. Moreover, we found that propofol (P25) decreased H9c2 cells apoptosis and autophagy that were associated with increased FoxO1 and FoxO3a expression. The protective effects of propofol (P25) against H/R injury were reversed by silencing FoxO1 or FoxO3a. Taken together, these results indicated that propofol postconditioning attenuated H9c2 cardiac cells apoptosis and autophagy induced by H/R injury through upregulating FoxO1 and FoxO3a under hyperglycemia.Support or Funding InformationSupported by National Natural Science Foundation of China (NSFC) grant (81970247)

Propofol alleviates oxidative stress via upregulating lncRNA-TUG1/Brg1 pathway in hypoxia/reoxygenation hepatic cells.

Reducing oxidative stress is an effective method to prevent hepatic ischaemia/reperfusion injury (HIRI). This study focuses on the role of propofol on the oxidative stress of hepatic cells and the involved lncRNA-TUG1/Brahma-related gene 1 (Brg1) pathway in HIRI mice. The mouse HIRI model was established and was intraperitoneally injected with propofol postconditioning. Hepatic injury indexes were used to evaluate HIRI. The oxidative stress was indicated by increasing 8-isoprostane concentration. Mouse hepatic cell line AML12 was treated with hypoxia and subsequent reoxygenation (H/R). The targeted regulation of lncRNA-TUG1 on Brg1 was proved by RNA pull-down, RIP (RNA-binding protein immunoprecipitation) and the expression level of Brg1 responds to silencing or overexpression of lncRNA-TUG1. Propofol alleviates HIRI and induces the upregulation of lncRNA-TUG1 in the mouse HIRI model. Propofol increases cell viability and lncRNA-TUG1 expression level in H/R-treated hepatic cells. In H/R plus propofol-treated hepatic cells, lncRNA-TUG1 silencing reduces cell viability and increased oxidative stress. LncRNA-TUG1 interacts with Brg1 protein and keeps its level via inhibiting its degradation. Brg1 overexpression reverses lncRNA-TUG1 induced the reduction of cell viability and the increase in oxidative stress. LncRNA-TUG1 silencing abrogates the protective role of propofol against HIRI in the mouse HIRI model. LncRNA-TUG1 has a targeted regulation of Brg1, and thereby affects the oxidative stress induced by HIRI. This pathway mediates the protective effect of propofol against HIRI of hepatic cell.

Retraction: The Early Stage Formation of PI3K-AMPAR GluR2 Subunit Complex Facilitates the Long Term Neuroprotection Induced by Propofol Post-Conditioning in Rats.

Retraction: The Early Stage Formation of PI3K-AMPAR GluR2 Subunit Complex Facilitates the Long Term Neuroprotection Induced by Propofol Post-Conditioning in Rats.

Effect of propofol postconditioning on necroptosis during hypoxia-reoxygenation injury in diabetic cardiomyocytes

Objective To evaluate the effect of propofol postconditioning on necroptosis during hypoxia-reoxygenation (H/R) injury in diabetic cardiomyocytes. Methods Normally cultured H9C2 cardiomyocytes were divided into 5 groups (n=19 each) using a random number table: control group (group C), high glucose group (group HG), H/R group, propofol postconditioning (group P) and solvent dimethyl sulfoxide (DMSO) control group (group DMSO). H9C2 cells were incubated for 48 h in DMEM culture medium containing 5.5 and 25 mmol/L glucose in group C and group HG, respectively.In group H/R, H9C2 cells were incubated for 48 h in DMEM culture medium containing 25 mmol/L glucose and then underwent H/R.H9C2 cells were incubated for 48 h in DMEM culture medium containing 25 mmol/L glucose and then underwent H/R, and propofol at the final concentration of 50 μmol/L was added at the onset of reoxygenation in group P. In group DMSO, H9C2 cells were incubated for 48 h in DMEM culture medium containing 25 mmol/L glucose and then underwent H/R, and DMSO at the final concentration of 150 μmol/L was added at the onset of reoxygenation.The model of cardiomyocyte H/R injury was established by subjecting cardiomyocytes to 6 h of hypoxia followed by 12 h of reoxygenation.At 12 h of reoxygenation, the cell viability was measured by CCK8 assay, the product of lactate dehydrogenase (LDH) in culture medium was measured, the level of reactive oxygen species (ROS) was determined by flow cytometry, cardiomyocyte apoptosis was detected by TUNEL, and the expression of receptor-interacting protein 1 (RIP1), RIP3, Bax, Bcl-2, activated caspase-3 and caspase-3 was determined by Western blot.The apoptotic rate and ratio of activated caspase-3/caspase-3 were calculated. Results Compared with group C, the cell viability was significantly decreased, the product of LDH was increased, the level of ROS and apoptotic rate were increased, the expression of RIP1, RIP3 and Bax was up-regulated, the expression of Bcl-2 was down-regulated, and the ratio of activated caspase-3/caspase-3 was increased in group HG (P 0.05). Conclusion The mechanism by which propofol postconditioning ameliorates H/R injury in diabetic cardiomyocytes may be related to inhibiting necroptosis. Key words: Propofol; Ischemic postconditioning; Diabetes mellitus; Myocytes, cardiac; Reperfusion injury; Necroptosis

Propofol postconditioning protects H9c2 cells from hypoxia/reoxygenation injury by inducing autophagy via the SAPK/JNK pathway.

Propofol postconditioning (P‑PostC) offers cardioprotection in mice, and the upregulation of autophagy protects cardiac cells against ischemia/reperfusion injury. The present study aimed to examine the effects of P‑PostC on the induction of autophagy and its potential roles in hypoxia/reoxygenation (H/R) injury. Rat heart‑derived H9c2 cells were exposed to H/R, comprising 6h of hypoxia followed by 4h of reoxygenation, as well as postconditioning with various concentrations of propofol at the onset of reperfusion. Lactate dehydrogenase (LDH) activity and the rate of cell apoptosis were measured to evaluate the degree of cardiomyocyte H/R injury. The induction of autophagy in myocytes subjected to H/R injury and P‑PostC was detected by western blotting and immunofluorescence. Furthermore, the activation of c‑Jun N‑terminal kinase (JNK) in cells treated with P‑PostC with or without co‑treatment with SP600125, an inhibitor of JNK, was also determined by western blotting. P‑PostC reduced the activity of LDH in the culture medium and the percentage of apoptotic cells compared with cells in the untreated H/R group. In addition, P‑PostC induced autophagy and promoted survival signaling in H9c2 cardiac myoblast cells. The inhibition of autophagy by 3‑methyladenine treatment diminished the cardioprotective effects of P‑PostC. These results indicated that propofol postconditioning promoted cell survival through the induction of autophagy in H9c2 cardiac cells, and that the stress‑activated protein kinase/JNK survival pathway may be partly involved in P‑PostC‑induced autophagy.

Intravenous Anesthetic Protects Hepatocyte from Reactive Oxygen Species-Induced Cellular Apoptosis during Liver Transplantation In Vivo.

Background Liver transplantation leads to liver ischemia/reperfusion (I/R) injury, resulting in early graft dysfunction and failure. Exacerbations of oxidative stress and inflammatory response are key processes in the development of liver I/R injury. Intravenous anesthetic propofol potent effects on free radical scavenging and protects livers against I/R injury. However, the role and mechanism of propofol-mediated hepatic protection in liver transplantation is poorly understood. The aim of this study was to evaluate the role of propofol postconditioning in the liver I/R injury after liver transplantation. Methods Forty-eight rats were randomly divided into six groups: rats receiving either sham operation or orthotopic autologous liver transplantation (OALT) in the absence or presence of propofol (high dose and low dose) postconditioning or intralipid control or VAS2870 (Nox2 special inhibitor). Eight hours after OALT or sham operation, parameters of organ injury, oxidative stress, inflammation, and NADPH-associated proteins were assessed. Results After OALT, severe liver pathological injury was observed that was associated with increases of serum AST and ALT, which were attenuated by propofol postconditioning. In addition, especially high dose of propofol postconditioning reduced TNF-α, IL-1β, IL-6, TLR4, and NF-κB inflammatory pathway, accompanied with decrease of neutrophil elastase activity, MPO activity, 8-isoprotane, p47phox and gp91phox protein expressions, and increase of SOD activity. Inhibition of Nox2 by VAS2870 conferred similar protective effects in liver transplantation. Conclusion Liver transplantation leads to severe inflammation and oxidative stress with NADPH oxidase activation. Propofol postconditioning reduces liver I/R injury after liver transplantation partly via inhibiting NADPH oxidase Nox2 and the subsequent inflammation and oxidative stress.

Neuroprotection by Propofol Post-Conditioning: Focus on PKMζ/KCC2 Pathway Activity.

Critical and major operations are often accompanied by brain ischemic complications. Previous studies found that propofol post-conditioning provided neuroprotective functions through upregulating the expression of potassium chloride cotransporter 2 (KCC2) in gamma-aminobutyric acid (GABA) interneurons. Membrane expression and phosphorylation represents KCC2 activity, which were modulated by a protein kinase C (PKC)-dependent mechanism. However, the role of propofol in increasing KCC2 phosphorylation and the involvement of protein kinase Mζ (PKMζ), a major subtype of PKC, in the KCC2 pathway remained unclear. In this study, we established middle cerebral artery occlusion model in rats to evaluate the long-term recovery of brain functions using behavioral experiments. KCC2 and PKMζ were assessed via western blot. We used the selective inhibitor, zeta inhibitory peptide (ZIP), to investigate the relationship between KCC2 and PKMζ. Intracellular chloride concentration in the hippocampal CA1 area was measured to determine KCC2 activity. We found that propofol, infused at a speed of 20mgkg-1h-1 for 2h at the onset of reperfusion, improved neurological deficits and cognitive dysfunction following ischemia/reperfusion injury. PKMζ expression was significantly upregulated, which improved KCC2 membrane expression and phosphorylation in the ischemic hippocampal CA1 area, and these effects could last up to 28days. But ZIP inhibited this process. Ultimately, we showed that propofol increased KCC2 phosphorylation and PKMζ was the upstream of KCC2. Propofol led to long-term recovery of brain functions by upregulating the activity of the PKMζ/KCC2 pathway.

Propofol post‐conditioning alleviates hepatic ischaemia reperfusion injury via BRG1‐mediated Nrf2/HO‐1 transcriptional activation in human and mice

To explore the effects of propofol post‐conditioning (PPC) on hepatic ischaemia/reperfusion injury (HIRI) and the potential mechanisms that might be involved in the interaction of Brahma‐related gene1(BRG1) and Nuclear‐related factor 2(Nrf2). Patients were randomized into PPC(n = 16) and non‐PPC(NPC)( n = 21) groups. Propofol(2 mg/kg) was infused within 10 min. of the onset of liver reperfusion during liver transplantation in the PPC group. Liver function tests, as well as Brg1, Nrf2, Heme oxygenase‐1(HO‐1) and NADPH:quinone oxidoreductase1(NQO1) expression levels were evaluated. CMV‐Brg1 mice were designed to investigate the role of Brg1 overexpression during HIRI. Brg1 and Nrf2 siRNA were used to examine the relationship between Brg1 and Nrf2/HO‐1 pathways in propofol‐mediated effects in a human hepatocyte(L02) hypoxia/reoxygenation(H/R) model. In patients, PPC attenuated both donor liver pathological and function injury, and reducing oxidative stress markers, compared to the NPC group, 24 hrs after surgery. PPC increased liver Brg1, Nrf2, HO‐1 and NQO1 expression. In mice, PPC reduced HIRI by decreasing liver oxidative stress and activating Nrf2/HO‐1 pathway, accompanied by up‐regulation of BRG1 expression. BRG1 overexpression activated Nrf2/HO‐1 transcription in CMV‐BRG1 mice during HIRI. In vitro, PPC significantly elevated expression of Nrf2, HO‐1 and NQO1, resulting in a reduction of cell DCFH‐DA and 8‐isoprostane levels and decreased lactate dehydrogenase levels, leading to an overall increase in cell viability. Moreover, the protective effects of propofol were partially abrogated in Nrf2‐knock‐down or BRG1‐knock‐down hepatocytes. Nrf2‐knock‐down drastically reduced protein expression of HO‐1 and NQO1, while Brg1‐knock‐down decreased HO‐1 expression. Propofol post‐conditioning alleviates HIRI through BRG1‐mediated Nrf2/HO‐1 transcriptional activation.

The effect of propofol postconditioning on the expression of K+-Cl--co-transporter 2 in GABAergic inhibitory interneurons of acute ischemia/reperfusion injury rats

It has been shown in our previous study that propofol postconditioning enhanced the activity of phosphatidylinositol-3-kinase (PI3K) and prevented the internalization of GluR2 subunit of α-amino-3-hydroxyl-5-methyl-4-isoxazolepropionic acid (AMPA) receptors, thus provided neuroprotection in cerebral ischemia/reperfusion (I/R) injury. Regarding inhibitory system in CNS, K+-Cl--co-transporter 2 (KCC2), a Cl- extruder, plays a critical role in gamma-aminobutyric acid (GABA) inhibitory effect in mature central neurons. However, the effect of propofol postconditioning on the expression of KCC2 in GABAergic interneurons is unclear. Therefore, in this article we describe the role of KCC2 in GABAergic interneurons in the ipsilateral hippocampal CA1 region of adult rats and the effects of propofol postconditioning on this region. Herein we demonstrate that propofol postconditioning (20mg/kg/h, 2h) improved rats׳ neurobehavioral abilities, increased the number of survival neurons, and up-regulated neuronal KCC2 expression in glutamic acid decarboxylase 67 (GAD67) expressing GABAergic interneurons in hippocampal CA1 region at 24h after I/R. In contrast, when rats were injected with the KCC2 antagonist, [(dihydroindenyl)oxy] alkanoic acid (DIOA), the neuroprotective effects induced by propofol postconditioning were reversed. Our study indicated that propofol postconditioning increased the expression of KCC2 in inhibitory GABAergic interneurons, thus providing acute neuroprotection to rats who had undergone cerebral I/R injury.

Effects of postconditioning with ischema and propofol on retinal injury induced by limb ischemia-reperfusion in rats

Objective To evaluate the effects of postconditioning with ischema and propofol on retinal injury induced by limb ischemia-reperfusion (LIR) in rats.Methods Twenty-four male Wistar rats were randomly divided into 3 groups (n =8 each) using a random number table:sham operation group (group S),group LIR,and propofol postconditioning + postconditioning + ischemic LIR group (group P + I + LIR).The model of LIR was established by separating and ligating the femoral artery and vein of bilateral hind limbs for 60 min followed by reperfusion.In group P + I + LIR,the animals were subjected to 4 episodes of 60 min ischemia-5 min reperfusion-5 min ischemia-5 min reperfusion and to 4 cycles of propofol 500 μg· kg-1 · min-1 infused intraperitoneally at the same time (during reperfusion)-no propofol infusion during second ischemia.At 120 min of reperfusion,blood samples were collected from the abdominal aorta for determination of serum malondialdehyde (MDA) concentrations.The eyeball was removed and the retina was cut into sections which were stained with H.E.and examined by microscopy.Results Compared with group S,the serum MDA concentration was significantly increased in group LIR,and no significant change was found in the serum MDA concentration in group P + I + LIR.The serum MDA concentration was significantly lower in group P + I + LIR than in group LIR.The structure of retina was normal in group S,oedema was found in all the layers of retina,vacuolar degeneration was observed in the most of ganglionic layers,and the structure disturbance was found in group LIR.The pathological changes of retina were significantly attenuated in group P + Ⅰ + LIR.Conclusion Postconditioning with ischema and propofol can attenuate retinal injury induced by LIR,and the mechanism is related to inhibition of lipid peroxidation in rats. Key words: Propofol ; Extremities ; Reperfusion injury ; Retina ; Ischemic postconditioning

Propofol Post-conditioning Protects against COS-7 Cells in Hypoxia/reoxygenation Injury by Induction of Intracellular Autophagy

【Background: Propofol (2.6-diisopropylphenol) is a widely used intravenous anesthetic agent for the induction and maintenance of anesthesia during surgeries and sedation for ICU patients. Propofol has a structural similarity to the endogenous antioxidant vitamin E and exhibits antioxidant activities.13) However, the mechanism of propofol on hypoxia/reoxygenation (H/R) injury has yet to be fully elucidated. We investigated how P-PostC influences the autophagy and cell death, a cellular damage occurring during the H/R injury. Methods: The groups were randomly divided into the following groups: Control: cells were incubated in normoxia (5% CO2, 21% O2, and 74% N2) without propofol treatment. H/R: cells were exposed to 24 h of hypoxia (5% CO2, 1% O2, and 94% N2) followed by 12 h of reoxygenation (5% CO2, 21% O2, and 74% N2). H/R + P-PostC: cells post-treated with propofol were exposed to 24 h of hypoxia followed by 12 h of reoxygenation. 3-MA + P-PostC: cells pretreated with 3-MA and post-treated propofol were exposed to 24 h of hypoxia followed by 12 h of reoxygenation Results: The results of our present study provides a new direction of research on mechanisms of propofol-mediated cytoprotection. There are three principal findings of these studies. First, the application of P-PostC at the onset of reoxygenation after hypoxia significantly increased COS-7 cell viability. Second, the cellular protective effect of P-PostC in H/R induced COS-7 cells was probably related to activation of intra-cellular autophagy. And third, the autophagy pathway inhibitor 3-MA blocked the protective effect of P-PostC on cell viability, suggesting a key role of autophagy in cellular protective effect of P-PostC. Conclusions: These data provided evidence that P-PostC reduced cell death in H/R model of COS-7 cells, which was in agreement with the protection by P-PostC demonstrated in isolated COS-7 cells exposed to H/R injury. Although the this study could not represent the protection by P-PostC in vivo, the data demonstrate another model in which endogenous mechanisms evoked by P-PostC protected the COS-7 cells exposed to H/R injury from cell death.】

Propofol Attenuates Cerebral Ischemia/Reperfusion Injury Partially Using Heme Oxygenase-1

To investigate the protective effects of propofol in brain ischemia/reperfusion injury and the role of heme oxygenase-1 (HO-1) in this process. Sprague-Dawley rats were randomly divided into 9 groups: sham-operated group; middle cerebral artery occlusion (MCAO) group; propofol 10, 20, and 50 mg/kg/h group (propofol 10, 20, 50 mg/kg/h infused at the onset of reperfusion for 30 min), ZnPPIX (a HO-1 activity inhibitor) group (ZnPPIX 20 μmol/kg administered 24 h before MCAO), and the other 3 groups received ZnPPIX followed by 10, 20, and 50 mg/kg/h propofol respectively. At 24 hours of reperfusion, neurological examinations were performed, and after neurological test, brain infarct size and volume, neuronal apoptosis, the level of HO-1 protein expression and HO-1 activity were observed in each group. Propofol significantly improved neurological deficits, reduced infarct volume, and attenuated neuron apoptosis compared with MCAO group alone. Increased HO-1 protein expression was observed in the ischemic penumbra and core of propofol group after transient MCAO. The selective HO-1 activity inhibitor, ZnPPIX, partially eliminated the neuroprotective effects of propofol. The neuroprotective effects of propofol postconditioning in brain ischemia/reperfusion injury may be partially through the induction of the HO-1 expression.

The Early Stage Formation of PI3K-AMPAR GluR2 Subunit Complex Facilitates the Long Term Neuroprotection Induced by Propofol Post-Conditioning in Rats

Previously, we have shown that the phosphoinositide-3-kinase (PI3K) mediated acute (24 h) post-conditioning neuroprotection induced by propofol. We also found that propofol post-conditioning produced long term neuroprotection and inhibited the internalization of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor GluR2 subunit up to 28 days post middle cerebral artery occlusion (MCAO). However, the relationship between PI3K with AMPA receptor GluR2 subunit trafficking in propofol post-conditioning has never been explored. Here we showed that propofol post-conditioning promoted the binding of PI3K to the C-terminal of AMPA receptor GluR2 subunit and formed a complex within 1 day after transient MCAO. Interestingly, the enhanced activity of PI3K was observed in the hippocampus of post-conditioning rats at day 1 post ischemia, whereas the decrease of AMPA receptor GluR2 subunit internalization was found up to 28 days in the same group. Administration of PI3K selective antagonist wortmannin inhibited the improvement of spatial learning memory and the increase of neurogenesis in the dentate gyrus up to 28 days post ischemia. It also reversed the inhibition of AMPA receptor GluR2 internalization induced by propofol post-conditioning. Together, our data indicated the critical role of PI3K in regulating the long term neuroprotection induced by propofol post-conditioning. Moreover, this role was established by first day activation of PI3K and formation of PI3K-AMPA receptor GluR2 complex, thus stabilized the structure of postsnaptic AMPA receptor and inhibited the internalization of GluR2 subunit during the early stage of propofol post-conditioning.

Propofol post‐conditioning confers ischemic cardioprotection via HO‐1/STAT3 signaling: role of peroxynitrite

Propofol, an aesthetic with antioxidant and peroxynitrite (ONOO−) scavenging property, when given during reperfusion attenuates myocardial ischemia/reperfusion (MI/R) injury. Heme oxygenase‐1 (HO‐1) and STAT3 are key proteins in postconditioning (PC) cardioprotection. We explored if Propofol PC (PPC) confers cardioprotection by scavenging ONOO− and activating the HO‐1/STAT3 pathway. Rats were subjected to 30 min coronary artery occlusion and 120 min reperfusion in vivo. Rats (n=7/group) were respectively treated with Propofol (2mg/kg), IPC, ONOO− generator SIN‐1(1.5 mg/kg), ONOO− scavenger FeTPPS (10 mg/kg) during MI/R. Also, primarily cultured cardiomyocytes were subjected to hypoxia/re‐oxygenation in the absence or presence of SIN‐1 or FeTPPS. PPC conferred similar cardioprotection to IPC in reducing postischemic myocardial infarction compared to control. FeTPPS enhanced PPC cardioprotection while SIN‐1 abolished PPC cardioprotection. HO‐1 and p‐STAT3 protein expression was increased in PPC group compared to control and it was associated with decreased ONOO− production and increased antioxidant capacity. PPC also attenuated post‐hypoxic lactate dehydrogenase in vitro. However, HO‐1/STAT3 gene knockdown abolished protective effect of PPC. In conclusion, PPC confers cardioprotection by scavenging ONOO− and activating the HO‐1/STAT3 pathway.Supported by RGC/GRF grant 782910M

Role of Akt-GSK3.BETA. signaling pathway in long-term neuroprotection induced by propofol postconditioning in a rat model of focal cerebral ischemia/reperfusion injury

Objective To evaluate the role of Akt-glycogen synthase kinase-3 beta (GSK3β) signaling pathway in the long-term neuroprotection induced by propofol postconditioning in a rat model of focal cerebral ischemia/reperfusion (I/R) injury.Methods Two hundred and sixteen male Sprague-Dawley rats,weighing 250-280 g,were randomly divided into 4 groups (n =54 each):sham operation group (group S),I/R group,intralipid control group (group I) and propofol postconditioning group (group P).The model of focal cerebral I/R injury was established by middle cerebral artery occlusion.Propofol 20 mg·kg-1 · h-1 was infused over 2 h starting from the onset of reperfusion in group P,the equal volume of normal saline was given in groups S and I/R and the equal volume of 10％ intralipid was given in group I.Six rats were chosen at 3,7,14 and 28 days after occlusion and sacrificed,and brains were removed for determination of the cerebral infarct size by TTC staining.Another 6 rats were chosen at 3,7,14 and 28 days after occlusion to detect the expression of Akt,GSK3β and phosphorylation of Akt and GSK3β by Western blot.The left 6 rats were chosen at 28 day after occlusion to measure the number of newly generated neurons in hippocampal dentate gyms on the ischemic side.Results Compared with group S,the cerebral infarct volume was significantly enlarged,the newly generated neurons number was increased in the other 3 groups,and the phosphorylation of Akt and GSK3β was decreased in groups I/R and I,while increased in group P (P ＜ 0.05).The cerebral infarct volume was significantly smaller,and the newly generated neurons number and phosphorylation of Akt and GSK3β were higher in group P than in group I/R (P ＜ 0.05).Conclusion The mechanism by which propofol postconditioning provides the long-term neuroprotection is related to Akt-GSK3β signaling pathway in a rat model of focal cerebral I/R injury. Key words: Protein-serine-threonine kinases; Glycogen synthase kinase 3; Propofol; Reperfusion injury; Brain

Effects of remifentanil postconditioning and combined remifentanil-propofol postconditioning on liver ischemia-reperfusion injury in rats

Objective To investigate the effects of remifentanil postconditioning and combined remifentanil-prupofol postconditioning on liver ischemia-reperfusion (I/R) injury in rats.Methods Thirty male SD rats weighing 220-280 g were randomly divided into 5 groups ( n =6 each):group sham operation (group Ⅰ ) ; group I/R (group Ⅱ ) ; group propofol postconditioning (group Ⅲ ) ; group remifentanil postconditioning (group Ⅳ ) and group combined propofol-remifentanil postconditioning (group Ⅴ ).In groups Ⅱ- Ⅴ the hepatic arteries and veins of middle and left were occluded for 30 min.In groups Ⅲ-Ⅴ propofol ( at 30 mg· kg- 1 · h - 1 ) and/or remifentanil (at 1 μg· kg- 1 · min- 1 ) were infused iv at the onset of reperfusion for 1 h.Blood samples were taken at the end of 1 h reperfusion for determination of serum AST,ALT activities and IL-8,IL-10 concentrations.The animals were sacrificed after blood sampling.Liver specimens were obtained for determination of c-fos and c-jun expression in liver cells by immuno-histochemistry and microscopic examination with scanning electron microscope.Results Liver I/R significantly increased serum AST and ALT activities and IL-8 and IL-10 concentrations and c-fos and cjun expression in liver ceils in group Ⅱ as compared with group Ⅰ.The serum AST and ALT activities,IL-8 concentration and the c-fos and c-jun expression in liver cells were significantly lower.and the serum IL-10 concentration was significantly higher in groups Ⅲ- Ⅴ than in group Ⅱ,but there were no significant differences among the groups Ⅲ - Ⅴ.The histo-pathological changes in the liver tissue were significantly attenuated in groups Ⅲ- v as compared with group Ⅱ.Conclusion Postconditioning with remifentanil and/or propofol can attenuate liver I/R injury by inhibiting inflammatory response and apoptosis in the liver cells,but there is no significant difference in the protective effects induced by postconditioning with remifentanil or propofol alone or in combination. Key words: Piperidines; Propofol; Reperfusion injury; Liver; Postconditioning

Propofol post-conditioning protects against cardiomyocyte apoptosis in hypoxia/reoxygenation injury by suppressing nuclear factor-kappa B translocation via extracellular signal-regulated kinase mitogen-activated protein kinase pathway

Perioperative myocardial ischaemia leads to an exceedingly high mortality. Previous studies have indicated that propofol pre-conditioning could mimic the cardioprotective effects of ischaemic pre-conditioning. The purpose of this study was to determine whether propofol post-conditioning is cardioprotective and to explore the possible molecular mechanism of propofol post-conditioning. Primary cultured neonatal rat cardiomyocytes were exposed to 12 h of hypoxia followed by 4 h of reoxygenation (H/R) and post-conditioned by different concentrations of propofol at the onset of reperfusion with and without a specific inhibitor of extracellular signal-regulated kinases (ERKs). Cell apoptosis and the generation of intracellular reactive oxygen species were measured using FACScalibur flow cytometric analysis. ERK1/2 phosphorylation and nuclear factor-kappa B (NF-κB) translocation were determined by western blot and immunofluorescence, respectively. Propofol post-conditioning enhanced cell viability (86.6 ± 6.5 versus 64.1 ± 3.4%) and reduced apoptosis (3.6 ± 0.4 versus 12.5 ± 2.1%) to protect cardiomyocytes against H/R injury. Meanwhile, propofol post-conditioning stimulated expression of phosphor-ERKs. H/R markedly induced p65 NF-κB nuclear translocation in cardiomyocytes, whereas propofol post-conditioning significantly suppressed H/R-primed NF-κB translocation. Moreover, addition of the mitogen-activated protein kinase kinase 1 inhibitor U0126 into cardiomyocytes 30 min before H/R eliminated the cardioprotection of propofol post-conditioning. Propofol exerts cardioprotection when administered at the early phase of reperfusion. The effect is mediated through decrease in cardiomyocyte apoptosis and NF-κB nucleus translocation potentially via ERK signalling pathways.