Objective To investigate the effects of ischemic postconditioning （IPO） on inflammatory response inischemia-reperfusion （IR） injury of rat lungs in vivo. Methods Forty SD rats were randomly divided into 5 groups inclu-ding a sham surgery group （S group），a 30-minute IR group （I/R-30 group），a 120-minute IR group（IR-120 group），a 30-minute IPO group （IPO-30 group），and a 120-minute IPO group （IPO-120 group）. There were 8 rats in each group. All therats received left thoracotomy after anesthesia. In the sham surgery group，a line was only placed around the left hilum butnot fastened. In the I/R-30 group and I/R-120 group，a line was fastened to block the blood flow of the left lung for 1 hour，then loosened for reperfusion for 30 minutes and 120 minutes respectively. In the IPO-30 group and IPO-120 group，afterblocking the blood flow of the left lung for 1 hour，the left hilum was fastened for 10 seconds and loosened for 10 seconds（repeating 3 times for 1 minute），then the line was loosened for 30 minutes and 120 minutes respectively. The levels of interleukin-10 （IL-10） in lung tissues and soluble intercellular adhesion molecule-1 （sICAM-1） in plasma were measured. Histopathological changes of lung tissues were observed and diffuse alveolar damage （DAD） scores was calculated.Results The levels of plasma sICAM-1 in the I/R-30 group and I/R-120 group were significantly higher than that of S group ［（2.140±0.250）μg/L vs. （0.944±0.188）μg/L，P=0.003；（2.191±0.230）μg/L vs. （0.944±0.188）μg/L，P=0.003］. IL-10levels in lung tissues in the I/R-30group and I/R-120 group were also significantly higher than that of S group［（15.922±0.606）pg/mg pro vs. （7.261±0.877）pg/mg pro，P=0.037；（17.421±1.232）pg/mg pro vs. （7.261±0.877）pg/mg pro，P=0.042］. Pathologic lesions of lung tissues in the I/R-30 group and I/R-120 group were more severe than that of S group. After IPO, plasma sICAM-1 levels in the IPO-30 group and IPO-120 group were significantly lower than those in the I/R-30group and I/R-120 group respectively ［（1.501±0.188）μg/L vs.（2.140±0.250）μg/L，P=0.038；（1.350±0.295）μg/L vs.（2.191±0.230）μg/L，P=0.005］. IL-10 levels in lung tissues in the IPO-30 group and IPO-120 group were significantly higherthan those in the I/R-30 group and I/R-120 group respectively ［（20.950±1.673）pg/mg pro vs.（15.922±0.606）pg/mgpro，P=0.008；（25.334±1.173）pg/mg pro vs.（17.421±1.232）pg/mg pro，P=0.006］. DAD scores in the IPO-30 group andIPO-120 group were significantly lower than those in the I/R-30 group and I/R-120 group respectively ［6.8±1.4 vs. 11.5±1.9，P=0.007；7.5±1.6 vs. 13.2±1.7，P=0.005］. Pathological lesions of the lung tissues of IPO groups were less severe than those of I/R groups. Conclusion IPO can attenuate IR injury by inhibiting inflammatory response in rat lungs.
Objective To explore the impact of ischemic postconditioning on ischemia-reperfusion injury in isolatedelderly rat hearts and their relation with P-Akt. Methods A total of 30 healthy elderly SD rats (21-23 months old， male or female) with their body weight of 450-500 g were divided into 3 groups: control group， ischemia-reperfusion group， and postconditioning group， with 10 rats in each group. Coronary artery blood flow，myocardial infarction size， phosphorylatedAkt （p-Akt） expression， and changes in myocardium and mitochondria were detected. Results Coronary artery blood flow of the postconditioning group was significantly higher than that of the ischemia-reperfusion group （6.4±1.2 ml/min vs.3.1±1.2 ml/min， P＜0. 01）， and myocardial infarction size of the postconditioning group was significantly smaller thanthat of the ischemia-reperfusion group （35.0%±2.0% vs. 55.7%±3.6%， Plt;0. 05）. The expression of P-Akt was significantlyhigher， and myocardial fibers and mitochondria were preserved better in the postconditioning group than the ischemia-reperfusion group. Conclusion Ischemic postconditioning can protect isolated elderly rat hearts against ischemia-reperfusion injury， which may be related to P-Akt activation.
Abstract： Ischemia postconditioning is a new concept based on ischemic preconditioning. It has become a hot topic in protection of ischemic-reperfusion injury because of its effective protection, relative ease of application, and postconditioning. However, its precise mechanisms and most effective application methods are still unclear. This review covers recent progress in the understanding, developments (in remote postconditioning and pharmacological postconditioning), applications to the protection of heart, lung, liver, kidney, and brain, mechanisms and appropriate protocol of ischemic post-conditioning.
Abstract： Objective To observe the expression changes of microRNA 1 （miRNA-1） and microRNA 21（miRNA-21） after ischemic preconditioning （IPC）, ischemic postconditioning （IPO） and remote ischemic preconditioning （RIPC）in an ischemia-reperfusion rat heart model in vitro, as well as the expression of their target protein heat shock protein 70 （HSP70） and programmed cell death 4 （PDCD4）, and evaluate whether miRNA are involved in endogenous cardio-protective mechanism. Methods The Langendorff-perfused Sprague-Dawley rat hearts were randomly assigned into one of the four groups, control group （CON group, n=12）, ischemia preconditioning group （IPC group， n=12） , ischemia postconditioning group （IPO group， n=12） and remote ischemia preconditioning group （RIPC group，n=12）. Cardiac function was digitalized and analyzed. The expression of HSP70, PDCD4, B-cell lymphoma/leukemia-2 （Bcl-2） and Bax was detected by Western blotting. The expression of miRNA-1 and miRNA-21 was detected by real-time reverse transcriotion-polymerase chain reaction （RT-PCR）. Assessment of cardiac infarct size and myocardial apoptosis was determined using triphenyltetrazolium chloride （TTC） assay and terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling assay （TUNEL） assay respectively. Results The expressions of miRNA-1 and miRNA-21 were up-regulated in IPC group, but the expression of miRNA-1 was down-regulated in RIPC group and IPO group （P＜0.05）. The expressionsof PDCD4, HSP70 and Bax were down-regulated in ‘conditioning’ groups compared with CON group （P＜0.05）. The expression of Bcl-2 was not statistically different among the four groups. The infarct size and the myocardial apoptosis in ‘conditioning’ hearts were significantly decreased compared with CON group （P＜0.05）. Conclusion The expressions of the miRNA-1 and miRNA-21 are different in IPC, RIPC and IPO groups, and their target proteins are not inversely correlated with the miRNAs in all the ‘conditioning’ groups.
Objective To investigate the protective effects of ischemic postconditioning (IPo) on ischemiareperfusion (I/R) myocardium and the relationship with mitochondrial adenosine triphosphate (ATP) sensitive K+ channels (mitoKATP) and provide evidences to the development of druginduced postconditioning. Methods Langendorff models were established in 40 Wistar rats which were divided into 5 groups by random number table with 8 rats in each group. Normal control group(NC group): the rat hearts were continuously reperfused by KrebsHenseleit bicarbonate buffer (K-HB) for 100 min without any other treatment; I/R group: the rat hearts underwent a 40-min global ischemia followed by a 60-min reperfusion; IPo group: after a 40-min global ischemia, the process of 10-second reperfusion followed by a 10-second ischemia was repeated 6 times, then there was a continuous 58min reperfusion; 5-hydroxydecanoic acid(5-HD) group: after a 40min global ischemia, hearts with 5HD(100 μmol/L) K-HB were reperfused for 15min and then perfused without 5HD for 45min；IPo+5-HD group: after a 40-min global ischemia, the process that the isolated hearts with 5-HD(100 μmol/L) KHB were reperfused for 10second followed by a 10second ischemia was repeated 6 times, then the hearts with 5-HD(100 μmol/L) KHB were continuously [CM(159mm]perfused for 13-min followed by reperfusion without 5-HD(100 μmol/L) K-HB for 45-min. The cardiac function,coronary flow(CF), cardiac troponin I(cTnI) content in coronary effluent, the area of acute myocardial infarction (AMI) and myocardial ultrastructure were observed. Results Left ventricular developed pressure(74.3±3.3 mm Hg vs. 57.1±3.3 mm Hg,t=1300, P=0.000),+dp/dtmax(1 706.6±135.6 mm Hg/s vs. 1 313.3±96.2 mm Hg/s,t=6.28,P=0.000),－dp/dtmax(1 132.8±112.1 mm Hg/s vs. 575.7±67.7 mm Hg/s,t=13.48, P=0.000) and CF(6.49±0.30 ml/min vs. 3.70±0.24 ml/min,t=28.6,P=0.000) in IPo group were higher than those in I/R group. Left ventricular enddiastolic pressure(10.9±1.7mm Hg vs. 26.2±1.5 mm Hg,t=－19.21, P=0000)and cTnI content in coronary effluent (0.62±0.01 ng/ml vs. 0.71±0.01 ng/ml, t=-12.00,P=0.000) were lower than those in I/R group; the area of AMI decreased 20.8％ compared with that in I/R group (Plt;0.05). The myocardial protective effect in IPo+5HD group was similar with that in IPo group, but lower than that in IPo group. The electron microscope showed that IPo and IPo+5HD could reduce myocardial fiber damage and mitochondrial damage caused by I/R. Conclusion IPo can protect I/R myocardium, which is achieved mainly by activating mitoK-ATP channels.
ObjectivesTo explore the mechanisms by which ischmic preconditioning (IPC), ischemic postconditioning (IPO) and IPCIPO exert influence on ischemic reperfusion injury (IRI) of the graft of SD rat after pancreas transplantation. MethodsAfter the establishment of diabetic SD rats model by using streptozotocin, 24 rats suffered from pancreas transplantation and were randomly averagely divided into four groups: I/R group, IPC group, IPO group, and IPC-IPO group. Six diabetic SD rats suffered with sham operation were served as SO group. The blood glucose level of rats in each group was detected before and after reperfusion, the contents of malonaldehyde (MDA) and super oxide dismutase (SOD) of pancreas allograft were tested at 2 h after reperfusion, and the apoptosis index (AI) of pancreas allograft was monitored by using TUNEL method. ResultsThe blood glucose level of rats in each group was not significantly different (Pgt;0.05). In SO group, the blood glucose level of rats was significantly higher than other groups (Plt;0.01). The blood glucose levels of rats after reperfusion decreased from the levels before reperfusion in I/R group, IPC group, IPO group, and IPC-IPO group (Plt;0.05 or Plt;0.01), furthermore the blood glucose level of rats in I/R group was significantly higher than that in abovementioned three groups (Plt;0.01), although among which the difference was not markedly (Pgt;0.05). When compared with I/R group, the MDA contents of rats after reperfusion in IPC group, IPO group， and IPC-IPO group decreased (Plt;0.01), while the SOD contents of rats after reperfusion increased (Plt;0.01). In rats of SO group, the MDA and SOD contents were significantly higher and lower than other groups, respectively (Plt;0.01). The MDA and SOD contents in IPC group, IPO group, and IPC-IPO group were not different (Pgt;0.05). The AI of pancreas allograft at 2 h after reperfusion in I/R group 〔(47.31±4.52)%〕, IPC group 〔(26.25±3.17)%〕, IPO group 〔(24.73±3.62)%〕, and IPC-IPO group 〔(25.5±4.15)%〕 were higher than that in SO group 〔(3.16±0.53)%〕, Plt;0.01. The AI of pancreas allograft in IPC group, IPO group, and IPC-IPO group were not different (Pgt;0.05), but they were lower than that in I/R group (Plt;0.01). Pathological results showed that injury of pancreas allograft in I/R group was most severe. ConclusionsIPO and IPC are associated with comparable effectiveness to protect graft from IRI during pancreas transplantation. The combined protective effects of IPC and IPO do not appear to be additive, which is equal to IPC or IPO alone.
Objective To study the mechanism of alleviating lung ischemia-reperfusion injury by postischemic treatment with namefene hydrochloride, and explore the optimal timing of drug treatment throughout the disease course. Methods A total of 60 rats were randomly divided into six groups with 10 rats in each group: a sham group, a model group, a nalmefene A (NA) group, a nalmefene B (NB) group, a nalmefene C (NC) group and a nalmefene D (ND) group. The sham group without drug treatment was not treated with ischemia-reperfusion. The lung ischemia-reperfusion model was established by occlusion of the left pulmonary hilum in the model group without drug treatment. After ischemic treatment, the NA, NB, NC and ND groups were respectively injected with nalmefene (15 μg/kg) by the tail vein at 5 min before, 10 min, 30 min and 60 min after pulmonary circulation reperfusion. At the 3rd hour after reperfusion, all rats were sacrificed and the specimens from the upper lobe of the left lung tissue were preserved to observe pulmonary lesions, detect wet/dry weight ratio and the activity of myeloperoxidase (MPO), the expressions of tumor necrosis factor-α (TNF-α), Toll-like receptor 2 (TLR2) mRNA and MyD88 mRNA as well as the expressions of TLR2, MyD88, NF-κB p65 and p-NF-κB p65 in lung tissue. Results There were different degrees of alveolar septal destruction, obvious pulmonary interstitial edema, the infiltration of inflammatory cell, the exudationred of blood cell in the mesenchyme, and the collapse of partial alveolar in the model group and the NA, NB, NC, ND groups. In terms of wet/dry weight ratio, the score of lung tissue injury, the activity of MPO, the expressions of TNF-α, TLR2 mRNA and MyD88 mRNA as well as the expressions of TLR2, MyD88, NF-κB p65 and p-NF-κB p65 in lung tissue, the model group were significantly higher than the sham group (P<0.01); there was no significant difference between the ND group and the model group (P>0.05). The corresponding test values of the nalmefene groups with post-ischemic treatment showed the characteristics of ND group> NC group> NB group> NA group (P<0.01). Conclusion The effect of nammefene on alleviating lung ischemia-reperfusion injury is closely related to the inhibition of TLR2, MyD88, NF-κB p65 and phosphorylation of NF-κB p65 with a characteristic of time-dependent manner.