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Objective:To investigate the role of Caveolin (Cav-3)/extracellular signal-regulated kinase (ERK) signaling pathway in reduction of myocardial ischemia-reperfusion (I/R) injury by morphine preconditioning in rats with chronic heart failure.Methods:Clean-grade healthy adult male Sprague-Dawley rats, weighing 200-250 g, were used in this study.Chronic heart failure was induced by ligating the left anterior descending coronary artery for 6 weeks.Thirty-six Langendorff-perfused hearts with chronic heart failure were divided into 4 groups ( n=9 each) by a random number table method: myocardial I/R group (group IR), morphine preconditioning group (group MP), morphine preconditioning plus methyl-β-cyclodextrin group (group MP+ MβCD), and methyl-β-cyclodextrin group (group MβCD). Global myocardial I/R was induced by 30 min ischemia followed by 120 min reperfusion.In group MP, after 15 min of equilibration, hearts were subjected to 3 cycles of 5 min perfusion with K-H solution containing 1 μmol/L morphine for preconditioning followed by 5 min perfusion with K-H solution, 30 min in total, and after the end of treatment, hearts were subjected to 30 min ischemia followed by 120 min reperfusion.In group MP+ MβCD, hearts were perfused with K-H solution containing 200 μmol/L methyl-β-cyclodextrin at 10 min before preconditioning with morphine, and the other treatments were similar to those previously described in group MP.In group MβCD, hearts were perfused with K-H solution containing 200 μmol/L methyl-β-cyclodextrin at 40 min before ischemia, and the other treatments were similar to those previously described in group IR.At the end of 15 min of equilibration (T 0) and 5 and 10 min of reperfusion (T 1, 2), coronary outflow was collected for determination of actate dehydrogenase (LDH) activity by chemical colorimetry.Myocardial infarct size (IS) and area at risk (AAR) were measured, and IS/AAR was calculated at the end of 120 min reperfusion.Myocardial tissues of left ventricle were taken to detect the expression of Cav-3, ERK1/2 and phosphorylated ERK1/2 (p-ERK1/2) by Western blot, and p-ERK1/2/ERK1/2 ratio was calculated. Results:Compared with group IR, IS, IS/AAR and LDH activity in coronary outflow were significantly decreased, the expression of Cav-3 was up-regulated, and p-ERK1/2/ERK1/2 ratio was increased in group MP ( P<0.05). Compared with group MP, IS, IS/AAR and LDH activity in coronary outflow were significantly increased, the expression of Cav-3 was down-regulated, and p-ERK1/2/ERK1/2 ratio was decreased in group MP+ MβCD ( P<0.05). Conclusions:The mechanism by which morphine preconditioning reduces I/R injury may be related to activation of Cav-3/ERK signaling pathway in rats with chronic heart failure.
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Objective:To compare the performance of rapid tests for HIV-1 antibody detection in serum and urine specimens of men who have sex with men (MSM) for investigating suitable technology in the prevention and control of AIDS in Beijing.Methods:A total of 874 cases of MSM were recruited in the AIDS clinic of Beijing Center for Disease Prevention and Control. HIV-1/2 antibody rapid test kit (Kit A, Alere Determine), urine HIV-1 antibody rapid test kit (Kit B, Wantai Biological Pharmacy) and HIV-1/2 antibody Western blot kit (Kit C, IMT) were used for antibody detection. The sensitivity, specificity and consistency of the three rapid test kits for HIV-1 antibody detection in serum and urine specimens were analyzed.Results:Among the 874 cases of MSM, 447 were positive for HIV-1 antibody (51.14%) and 427 were negative. One false negative result occurred by using Kit A and 23 by using Kit B. Taking Kit C as reference, the sensitivity of Kit A and Kit B was 99.78% and 94.85%, respectively; the specificity of both was 100%; the overall consistency was 99.89% ( Kappa=0.998) and 97.37% ( Kappa=0.947), respectively. Conclusions:Although the sensitivity of urine rapid test kit was not as sensitive as serum rapid test kit, it was more suitable for self-test due to its convenience in sampling, high safety and high accessibility. It was suggested that urine rapid test kit should be popularized in MSM population for HIV-1 antibody screening.
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Recently, liposomes have been widely used in cancer therapeutics, but their anti-tumor effects are suboptimal due to limited tumor penetration. To solve this problem, researchers have made significant efforts to optimize liposomal diameters and potentials, but little attention has been paid to liposomal membrane rigidity. Herein, we sought to demonstrate the effects of cholesterol-tuned liposomal membrane rigidity on tumor penetration and anti-tumor effects. In this study, liposomes composed of hydrogenated soybean phospholipids (HSPC), 1,2-distearoyl--glycero-3-phosphoethanolamine--[methoxy(polyethylene glycol)-2000] (DSPE-PEG) and different concentrations of cholesterol were prepared. It was revealed that liposomal membrane rigidity decreased with the addition of cholesterol. Moderate cholesterol content conferred excellent diffusivity to liposomes in simulated diffusion medium, while excessive cholesterol limited the diffusion process. We concluded that the differences of the diffusion rates likely stemmed from the alterations in liposomal membrane rigidity, with moderate rigidity leading to improved diffusion. Next, the tumor penetration and the anti-tumor effects were analyzed. The results showed that liposomes with moderate rigidity gained excellent tumor penetration and enhanced anti-tumor effects. These findings illustrate a feasible and effective way to improve tumor penetration and therapeutic efficacy of liposomes by changing the cholesterol content, and highlight the importance of liposomal membrane rigidity.
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Objective@#To evaluate the role of morphine preconditioning on necroptosis during myocardial ischemia-reperfusion (I/R) injury in the rats with heart failure.@*Methods@#Clean-grade adult male Sprague-Dawley rats, weighing 200-230 g, were injected with 2 mg/kg doxorubicin via the tail vein once a week for 6 consecutive weeks to establish the chronic heart failure model.Thirty rats with chronic heart failure at the end of 8th week were divided into 3 groups (n=10 each) using a random number table method: sham operation group (group S), I/R group and morphine preconditioning group (group MPC). Myocardial I/R was induced by occlusion of anterior descending branch of left coronary artery for 30 min followed by 120 min reperfusion in each group except group S. In group MPC, the rats were subjected to 3 cycles of 5-min infusion of 0.1 mg/kg morphine via the femoral vein at 5 min intervals before ischemia.The animals were sacrificed at the end of reperfusion, and the myocardial specimens were obtained for determination of the area at risk (AAR), infarct size (IS), expression of Fas mRNA (by quantitative real-time polymerase chain reaction) and expression of Fas, receptor-interacting protein 1 (RIP1) and RIP3 (by Western blot). The IS/AAR ratio was calculated.@*Results@#Compared with group S, the IS and IS/AAR ratio were significantly increased at the end of reperfusion, and the expression of Fas protein and mRNA, RIP1 and RIP3 was up-regulated in group I/R (P<0.05). Compared with group I/R, the IS and IS/AAR ratio were significantly decreased at the end of reperfusion, and the expression of Fas protein and mRNA, RIP1 and RIP3 was down-regulated in group MPC (P<0.05).@*Conclusion@#The mechanism by which morphine preconditioning reduces myocardial I/R injury is related to inhibiting necroptosis in the rats with heart failure.
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Objective To evaluate the role of morphine preconditioning on necroptosis during myocardial ischemia-reperfusion (I/R) injury in the rats with heart failure.Methods Clean-grade adult male Sprague-Dawley rats,weighing 200-230 g,were injected with 2 mg/kg doxorubicin via the tail vein once a week for 6 consecutive weeks to establish the chronic heart failure model.Thirty rats with chronic heart failure at the end of 8th week were divided into 3 groups (n=10 each) using a random number table method:sham operation group (group S),I/R group and morphine preconditioning group (group MPC).Myocardial I/R was induced by occlusion of anterior descending branch of left coronary artery for 30 min followed by 120 min reperfusion in each group except group S.In group MPC,the rats were subjected to 3 cycles of 5min infusion of 0.1 mg/kg morphine via the femoral vein at 5 min intervals before ischemia.The animals were sacrificed at the end of reperfusion,and the myocardial specimens were obtained for determination of the area at risk (AAR),infarct size (IS),expression of Fas mRNA (by quantitative real-time polymerase chain reaction) and expression of Fas,receptor-interacting protein 1 (RIP1) and RIP3 (by Western blot).The IS/AAR ratio was calculated.Results Compared with group S,the IS and IS/AAR ratio were significantly increased at the end of reperfusion,and the expression of Fas protein and mRNA,RIP1 and RIP3 was up-regulated in group I/R (P＜0.05).Compared with group I/R,the IS and IS/AAR ratio were significantly decreased at the end of reperfusion,and the expression of Fas protein and mRNA,RIP1 and RIP3 was down-regulated in group MPC (P＜0.05).Conclusion The mechanism by which morphine preconditioning reduces myocardial I/R injury is related to inhibiting necroptosis in the rats with heart failure.
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Objective To evaluate the relationship between excitability of neurons in hypothalamic paraventricular nucleus (PVN) and central nervous regulatory mechanism of myocardial ischemia-reperfusion (I/R) injury in rats.Methods Clean-grade healthy adult male Sprague-Dawley rats,in which PVN catheters were successfully implanted,aged 6-8 weeks,weighing 260-300 g,were divided into 4 groups (n =6 each) using a random number table method:sham operation group (S group),myocardial I/R group (I/R group),γ-aminobutyric acid group (GABA group) and L-glutamic acid group (L-Glu group).Myocardial ischemia was induced by occlusion of the left anterior descending coronary artery for 30 min followed by 120-min reperfusion.Normal saline 2.4 μl/h was infused for 50 min via the PVN catheter starting from 10 min before ischemia in S and I/R groups.GABA 30 μmol/L and L-glutamic acid 30 μmol/L were infused for 50 min via the PVN catheter at a rate of 2.4 μl/h starting from 10 min before ischemia in GABA and L-Glu groups.The heart rate (HR) and mean arterial pressure (MAP) were recorded at 10 min before ischemia (T0),beginning of ischemia (T1),30 min of ischemia (T2) and 120 min of reperfusion (T3).Rate-pressure product (RPP) was calculated.Blood samples were collected at T3 for determination of plasma cardiac troponin I (cTnI) concentrations by chemiluminescence assay.Rats were then sacrificed and myocardial specimens were obtained for measurement of myocardial infarct size (IS) and area at risk (AAS),and IS/AAR percentage was calculated.PVN tissues were taken to detect the expression of cfos by Western blot.Results No myocardial infarction was found in group S,and myocardial infarction was marked in the other three groups.Compared with group S,the plasma cTnI concentrations were significantly increased,and the expression of c-fos in PVN was up-regulated in I/R,GABA and L-Glu groups (P＜0.05),and MAP,HR and RPP were significantly decreased at T1-3 in I/R and GABA groups and at T3 in group L-Glu (P＜0.05).Compared with group I/R,IS and IS/AAR percentage were significantly decreased,the plasma cTnI concentrations were decreased,the expression of c-fos in PVN was down-regulated,and HR,MAP and RPP were decreased at T1,2 in group GABA,and IS and IS/AAR percentage were significantly increased,the plasma cTnI concentrations were increased,the expression of c-fos in PVN was up-regulated,and HR,MAP and RPP were increased at T1,2 in group L-Glu (P＜0.05).Conclusion Excitability of neurons in hypothalamic PVN is involved in central nervous regulatory mechanism of myocardial I/R injury in rats:decreased excitability can attenuate myocardial I/R injury and increased excitability aggravates myocardial I/R injury.
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Objective To evaluate the role of μ opioid receptor in morphine preconditioning-induced reduction of myocardial ischemia-reperfusion (I/R) injury in rats with chronic heart failure.Methods Adult male Sprague-Dawley rats,weighing 170-230 g,in which chronic heart failure was induced by injecting doxorubicin via the tail vein,were studied.The rats were sacrificed and their hearts were excised and perfused in a Langendorff apparatus with K-H solution saturated with 95％ O2-5％ CO2 at 37 ℃.Forty isolated rat hearts with I/R injury were randomly divided into 4 groups (n=10 each):group I/R,morphine preconditioning group (group MP),μ opioid receptor antagonist CTOP plus morphine preconditioning group (group CTOP+MP) and CTOP group.Myocardial I/R was induced by occlusion of the left coronary artery for 30 min followed by 120 min of reperfusion.In group MP,the hearts were perfused with K-H solution for 15 min,with K-H solution containing 1 μmol/L morphine for 5 min and with K-H solution for 5 min,3 cycles in total,and then the model of myocardial I/R was established.The hearts were perfused with K-H solution containing 1 μmol/L CTOP starting from 10 min before morphine preconditioning until 5 min of ischemia in group CTOP + MP.The hearts were perfused with K-H solution containing 1 μmol/L CTOP starting from 40 min before ischemia until 5 min of ischemia in group CTOP.The coronary effluent was collected at 15 min of equilibration (baseline) and 5 and 10 min of reperfusion to detect the activity of lactate dehydrogenase (LDH).Myocardial infarct size (IS) and the area at risk (AAR) were measured by 2,3,5-triphenyl-tetrazolium staining,and IS/AAR percentage was calculated.The expression of Bcl-2 and Bax mRNA was determined using uantitative real-time polymerase chain reaction,and the ratio of Bcl-2/Bax was calculated.Results Compared with group I/R,the IS and IS/AAR percentage were significantly decreased,the activity of LDH in coronary effluent was decreased,the expression of Bax mRNA was downregulated,the expression of Bcl-2 mRNA was up-regulated,and the Bcl-2/Bax ratio was increased in group MP (P＜0.05),and no significant change was found in the IS or IS/AAR percentage in CTOP and CTOP+ MP groups (P＞0.05).Compared with group MP,the IS and IS/AAR percentage were significantly increased,the activity of LDH in coronary effluent was increased,the expression of Bax mRNA was up-regulated,the expression of Bcl-2 mRNA was down-regulated,and the Bcl-2/Bax ratio was decreased in group CTOP+MP (P＜0.05).Conclusion The mechanism by which morphine preconditioning reduces myocardial I/R injury may be related to activating μ opioid receptors and thus maintaining the balance between Bcl2 and Bax gene expression in the rats with chronic heart failure.
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Objective To evaluate the role of activation of astrocytes in the spinal cord in myocardial ischemia-reperfusion (I/R) injury in rats.Methods Eighteen healthy adult male Sprague-Dawley rats,in which intrathecal catheters were successfully implanted,weighing 250-300 g,were divided into 3 groups (n =6 each) using a random number table method:sham operation group (group Sham),myocardial I/R group (group I/R) and an astrocyte inhibitor fluorocitrate group (group I/R+FC).Myocardial ischemia was induced by 30 min occlusion of left anterior descending branch of coronary artery followed by 120 min reperfusion in chloral hydrate-anesthetized rats.Fluorocitrate 10 μl (1 nmol) was intrathecally infused at a constant rate starting from 30 min before ischemia in group I/R+ FC.Arrhythmia was scored according to the results of electrocardiography during I/R.Arterial blood samples were collected at 120 min of reperfusion to determine the serum cardiac troponin Ⅰ (cTnⅠ) concentration by chemiluminescence assay.The animals were then sacrificed,myocardial specimens were taken for measurement of the infarct size,and T2-6 segments of the spinal cord were harvested for determination of the expression of glial fibrillary acidic protein (GFAP) (by Western blot).Results Compared with group Sham,the serum cTnⅠ concentration,arrhythmia score,and myocardial infarct size were significantly increased,and the expression of GFAP was up-regulated in I/R and I/R+FC groups (P＜0.05).Compared with group I/R,the serum cTnⅠ concentration,arrhythmia score,and myocardial infarct size were significantly decreased,and the expression of GFAP was down-regulated in group I/R+FC (P＜0.05).Conclusion The activation of astrocytes in spinal cord is involved in myocardial I/R injury in rats.
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Objective To analyze the survival time of HIV/AIDS cases and related factors in Beijing from 1995 to 2015. Methods A retrospective cohort study was conducted to analyze the data of 12874 HIV/AIDS cases. The data were collected from Chinese HIV/AIDS Comprehensive Information Management System. Life table method was applied to calculate the survival proportion, and Cox proportion hazard regression model were used to identify the factors related with survival time. Results Among 12874 HIV/AIDS cases, 303 (2.4%) died of AIDS related diseases; 9346 (72.6%) received antiretroviral therapy. The average survival time was 226.5 months (95%CI:223.0-230.1), and the survival rates of 1, 5, 10, and 15 years were 98.2%, 96.4%, 93.2%, and 91.9%respectively. Multivariate Cox proportion hazard regression model showed that AIDS phase (HR=1.439, 95%CI: 1.041-1.989), heterosexual transmission (HR=1.646, 95%CI: 1.184-2.289), being married (HR=2.186, 95%CI:1.510-3.164);older age (≥60 years) at diagnosis (HR=6.608, 95%CI:3.546-12.316); lower CD4+T cell counts at diagnosis (<350 cells/μl) (HR=8.711, 95%CI: 5.757-13.181); receiving no antiretroviral therapy (ART) (HR=18.223, 95%CI: 13.317-24.937) were the high risk factors influencing the survival of AIDS patients compared with HIV phase, homosexual transmission, being unmarried, younger age (≤30 years), higher CD4+T cell count (≥350 cell/μl) and receiving ART. Conclusion The average survival time of HIV/AIDS cases was 226.5 months after diagnoses. Receiving ART, higher CD4+T cell counts at the first test, HIV phase, younger age, being unmarried and the homosexual transmission were related to the longer survival time of HIV/AIDS cases. Receiving no ART, the lower CD4+T cell counts at the first test, AIDS phase, older age, being married and heterosexual transmission indicated higher risk of death due to AIDS.
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Objective To evaluate the effect of sevoflurane postconditioning on inositol-requiring enzyme 1 (IRE1) signaling pathway in the brain tissues in a rat model of hemorrhagic shock and resuscitation (HSR).Methods Sixty healthy adult male Sprague-Dawley rats,weighing 300-350 g,were divided into 5 groups (n =12 each) using a random number table:sham operation group (group Sham),group HSR,1.2％ sevoflurane postconditioning group (group SP1),2.4％ sevoflurane postconditioning group (group SP2) and 3.6％ sevoflurane postconditioning group (group SP3).Hemorrhagic shock was induced by withdrawing blood (40％ of the total blood volume) from the right common carotid artery over an interval of 30 min,and 1 h later the animals were resuscitated with the shed blood infused via the left jugular vein over 30 min.SP1,SP2 and SP3 groups inhaled 1.2％,2.4％ and 3.6％ sevoflurane,respectively,for 30 min starting from the beginning of infusion of the shed blood.Oxygen was inhaled for 30 min instead of sevoflurane in Sham and HSR groups.Mean arterial pressure was recorded before withdrawing blood (T0),immediately after the end of withdrawing blood (T1),at 30 min after the end of withdrawing blood (T2),before infusion of the shed blood (T3),and immediately after infusion of the shed blood (T4).Arterial blood samples were obtained at T0,T1,T3 and T4 for blood gas analysis.Morris water maze test was performed at 72 h after the end of infusion of the shed blood.The animals were then sacrificed,and brains were removed for determination of the expression of caspase-3 in hippocampal CA1 region (by immunohistochemistry) and expression of IRE1 and X-box binding protein 1 (XBP1) in hippocampal tissues (by Western blot).Results Compared with group Sham,mean arterial pressure was significantly decreased at T1-3,the pH value and base excess were decreased,lactic acid concentrations were increased,the escape latency was prolonged,the frequency of crossing the original platform was decreased,and the expression of caspase-3 in hippocampal CA1 regitn and IRE1 and X BP 1 in hippocampal tissues was up-reg ulated in group HSR (P＜0.05).Compared with group HSR,the escape latency was significantly shortened,the frequency of crossing the original platform was increased,and the expression of caspase-3 in hippocampal CA1 region and IRE1 and XBP1 in hippocampal tissues was down-regulated in SP2 and SP3 groups (P＜0.05),and no significant changes were found in the parameters mentioned above in group SP1 (P＞0.05).Conclusion The mechanism by which sevoflurane postconditioning reduces brain injury may be related to activating IRE1 signaling pathway in the brain tissues in a rat model of HSR.
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Objective To analyze the survival time of HIV/AIDS cases and related factors in Beijing from 1995 to 2015. Methods A retrospective cohort study was conducted to analyze the data of 12874 HIV/AIDS cases. The data were collected from Chinese HIV/AIDS Comprehensive Information Management System. Life table method was applied to calculate the survival proportion, and Cox proportion hazard regression model were used to identify the factors related with survival time. Results Among 12874 HIV/AIDS cases, 303 (2.4%) died of AIDS related diseases; 9346 (72.6%) received antiretroviral therapy. The average survival time was 226.5 months (95%CI:223.0-230.1), and the survival rates of 1, 5, 10, and 15 years were 98.2%, 96.4%, 93.2%, and 91.9%respectively. Multivariate Cox proportion hazard regression model showed that AIDS phase (HR=1.439, 95%CI: 1.041-1.989), heterosexual transmission (HR=1.646, 95%CI: 1.184-2.289), being married (HR=2.186, 95%CI:1.510-3.164);older age (≥60 years) at diagnosis (HR=6.608, 95%CI:3.546-12.316); lower CD4+T cell counts at diagnosis (<350 cells/μl) (HR=8.711, 95%CI: 5.757-13.181); receiving no antiretroviral therapy (ART) (HR=18.223, 95%CI: 13.317-24.937) were the high risk factors influencing the survival of AIDS patients compared with HIV phase, homosexual transmission, being unmarried, younger age (≤30 years), higher CD4+T cell count (≥350 cell/μl) and receiving ART. Conclusion The average survival time of HIV/AIDS cases was 226.5 months after diagnoses. Receiving ART, higher CD4+T cell counts at the first test, HIV phase, younger age, being unmarried and the homosexual transmission were related to the longer survival time of HIV/AIDS cases. Receiving no ART, the lower CD4+T cell counts at the first test, AIDS phase, older age, being married and heterosexual transmission indicated higher risk of death due to AIDS.
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Objective To evaluate the role of c-Jun N-terminal kinase (JNK) and p38 mitogen-activated protein kinase (p38MAPK) signaling pathways in reduction of ischemia-reperfusion (I/R) injury by morphine preconditioning in the rats with heart failure.Methods Adult male Sprague-Dawley rats,weighing 200-230 g,in which doxorubicin 2 mg/kg was injected via the tail vein once a week for 6 consecutive weeks to induce chronic heart failure,were studied.At the end of 8th week,45 rats with chronic heart failure were randomly divided into 5 groups (n =9 each) using a random number table:sham operation group (group S),group I/R,morphine preconditioning group (group MPC),SP600125 (JNK inhibitor) + morphine preconditioning group (group MSP) and SB203580 (p38MAPK inhibitor) + morphine preconditioning group (group MSB).Myocardial I/R was induced by 30 min occlusion of the anterior descending branch of the coronary artery followed by 120 min reperfusion in each group except group S.In group MPC,the rats were subjected to 3 cycles of 5-min infusion of 0.1 mg/kg morphine via the femoral vein at 5 min interval before ischemia.In MSP and MSB groups,SP600125 0.5 mg/kg and SB203580 0.2 mg/kg were injected via the femoral vein,respectively,at 10 min before morphine preconditioning.The animals were sacrificed at 120 min of reperfusion,and the myocardial specimens were obtained for determination of the total areas of right and left ventricles (LV+RV),area at risk (AAR),infarct size (IS),and expression of PKC δ in myocardial tissues (by immunohistochemistry),and IS/AAR ratio was calculated.Results There was no significant difference in LV+RV and AAR between the five groups (P＞0.05).Compared with group S,IS and IS/AAR were significantly increased,and the expression of PKC δ was upregulated in I/R and MSB groups (P＜0.05).Compared with group I/R,IS and IS/AAR were significantly decreased,and the expression of PKC δ was down-regulated in MPC and MSP groups (P＜0.05).Compared with group MPC,IS and IS/AAR were significantly increased,and the expression of PKC δ was upregulated in group MSB (P＜0.05),and no significant change was found in the parameters mentioned above in group MSP (P＞0.05).Conclusion Activation of p38MAPK signaling pathway is involved in reduction of myocardial I/R injury by morphine preconditioning,and the mechanism is related to down-regulation of PKC δ expression in rats with heart failure;JNK signaling pathway is not involved in this process.
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Objective To investigate the role of p38 mitogen-activated protein kinase (p38MAPK) signaling pathway in reduction of myocardial ischemia-reperfusion (I/R) injury by morphine preconditioning in the rats with chronic heart failure in vitro.Methods Adult male Sprague-Dawley rats,weighing 200-230 g,aged 6-7 weeks,in which doxorubicin 2 mg/kg was injected via the tail vein once a week for 6 consecutive weeks to induce chronic heart failure,were studied.At the end of 8th week,30 rats with chronic heart failure were randomly divided into 5 groups (n =6 each) using a random number table:sham operation group (group Sham),I/R group,morphine preconditioning group (group MPC),SB203580 (p38MAPK inhibitor) + morphine preconditioning group (group SBM),and SB203580 group (group SB).The hearts were quickly excised and passively perfused in a Langendorff apparatus and subjected to 30 min of occlusion of the anterior descending branch of the left coronary artery followed by 120 min of reperfusion to establish the model of myocardial I/R injury.After equilibration,the hearts were subjected to 3 cycles of 5 min perfusion with K-H solution containing morphine 1 μmol/L at 5-min intervals before ischemia in group MPC.In group SBM,the hearts were perfused with K-H solution containing SB203580 (5 μmol/L) for 45 min starting from l0 min before morphine preconditioning until 5 min of ischemia.In group SB,morphine preconditioning was not performed,and the hearts were only perfused with K-H solution containing SB203580 (5 μmol/L) starting from 40 min before ischemia until 5 min of ischemia.At 15 min of equilibration (baseline),5 and 10 min of reperfusion,the coronary effluent was collected to detect the activity of lactate dehydrogenase (LDH) using the chemical colorimetry.At 10 min of reperfusion,the expression of phosphor-p38MAPK (p-p38MAPK) in the myocardium was determined by Western blot in Sham,I/R and MPC groups.At 120 min of reperfusion,the area at risk (AAR),total areas of right and left ventricles (LV+RV),and infarct size (IS) were measured,and the IS/AAR ratio was calculated.Results Compared with group Sham,the LDH activity in coronary effluent during reperfusion and IS/AAR ratio were significantly increased in the other groups,and the expression of p-p38MAPK was significantly up-regulated in I/R and MPC groups (P＜0.05).Compared with group I/R,the LDH activity in coronary effluent during reperfusion was significantly decreased,the expression of p-p38MAPK was significantly up-regulated,and the IS and IS/AAR ratio were significantly decreased in group MPC (P＜0.05),and no significant change was found in the LDH activity in coronary effluent,IS and IS/AAR ratio in SBM and SB groups (P＞0.05).Compared with group MPC,the LDH activity in coronary effluent during reperfusion was significantly increased,and the IS and IS/AAR ratio were significantly increased in group SBM (P＜0.05).Conclusion The mechanism by which morphine preconditioning reduces myocardial I/R injury is related to activation of p38MAPK signaling pathway in the rats with chronic heart failure in vitro.
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Objective To investigate the effect of intrathecal morphine preconditioning on the expression of nerve growth factor (NGF) in the dorsal root ganglia (DRG) in a rat model of myocardial ischemia-reperfusion (I/R).Methods Thirty healthy adult male Sprague-Dawley rats in which intrathecal catheters were successfully placed without complications,weighing 250-350 g,were randomly divided into 5 groups (n =6 each) using a random number table:sham operation group (S group),I/R group,intrathecal morphine preconditioning group (ITMP group),μ receptor antagonist CTOP + intrathecal morphine preconditioning group (CTOP + ITMP group),and CTOP control group (CTOP group).Myocardial ischemia was induced by 30 min of occlusion of the anterior descending branch of the left coronary artery followed by 120 min of reperfusion in all the groups except S group.Intrathecal morphine preconditioning was produced by 3 cycles of 5 min intrathecal injection of morphine 3 μg/kg (10 μl) at 5 min intervals within 30 min before ischemia in ITMP group.In CTOP+ITMP and CTOP groups,1 μg/μ1 CTOP 10 μl was injected intrathecally at 10 min before morphine preconditioning and 40 min before ischemia,respectively.At 120 min of reperfusion,the rats were sacrificed,and myocardial specimens were obtained for determination of myocardial infarct size,and DRGs were removed for determination of the expression of NGF by using immunohistochemistry and Western blot.Results Compared with S group,the myocardial infarct size was significantly increased,and the expression of NGF in DRGs was significantly up-regulated in I/R group (P＜0.05).Compared with I/R group,the myocardial infarct size was significantly decreased,and the expression of NGF in DRGs was significantly down-regulated in ITMP group (P＜ 0.05),and no significant change was found in the parameters mentioned above in CTOP group (P＞0.05).Compared with ITMP group,the myocardial infarct size was significantly increased,and the expression of NGF in DRGs was significantly up-regulated in CTOP+ITMP and CTOP groups (P＜0.05).Conclusion The mechanism by which intrathecal morphine preconditioning reduces myocardial I/R injury is related to activation of spinal μ receptors,inhibition of NGF expression in DRGs,and reduction of responses to noxious stimulation in the rats.
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Aim To investigate the effects of lentivirus mediated nerve growth factor ( NGF) gene silencing on pheochromocytoma cells ( PC12 ) and the possible mechanisms .Methods The NGF shRNA expression vector was constructed .PC12 cells were randomly divi-ded into five groups (n=3 each) as follows: negative control group ( NC ) , control lentivirus group ( LV CON) , lentivirus NGF shRNA1 group ( LV shNGF1 ) , lentivirus NGF shRNA2 group(LV shNGF2), lentivir-us NGF shRNA3 group(LV shNGF3).The cells in NC group were cultured in DMEM/HG and polybrene me-dium, while others were cultured in DMEM/HG, poly-brene and corresponding lentivirus medium .After the treatment, the infection efficiency was determined by fluorescent microscope .Relative expression of NGF , extracellular signal-regulated kinase ( ERK1/2 ) and p-ERK1/2 were assessed by Western blot .The expres-sion of NGF mRNA was analyzed by quantitative re-verse transcription polymerase chain reaction ( qRT-PCR) .The differentiation degree was valued according to the length of neuritis and max diameter of cells .The cell viability was detected by CCK-8.Results The in-fection efficiency in PC12 cells reached over 90%. Compared with NC group , the relative expression of NGF mRNA and NGF protein was significantly down-regulated ( P<0.05 ) .There was no difference in the expression of ERK1/2 protein and cell viability .The expression of p-ERK1/2 protein was markedly down-regulated in LV shNGF3 group ( P<0.01 ) .The cells morphology was changed , and the length of neuritis and max diameter of cells were strained in LV shNGF 3 group than those in NC group ( P<0.01 ) .Conclusion Lentivirus-mediated NGF gene silencing inhibits the differentiation of PC12 cells through suppressing the activation of ERK1/2.
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Objective To evaluate the effect of sevoflurane postconditioning on the expression of activating transcription factor 6 (ATF6) in the brain tissues in a rat model of hemorrhagic shock and resuscitation.Methods Thirty-six pathogen-free healthy adult male Sprague-Dawley rats,weighing 300-350 g,were randomized into 3 groups (n=12 each) using a random number table:sham operation group (group S);hemorrhagic shock and resuscitation group (group HSR);sevoflurane postconditioning group (group SP).Hemorrhagic shock was induced by withdrawing blood (40％ of the total blood volume) from the right common carotid artery over an interval of 30 min,and 1 h later the animals were resuscitated with infusion of the shed blood via the left jugular vein over 30 min.In group SP,2.4％ sevoflurane was inhaled for 30 min starting from the onset of infusion of the shed blood.Mean arterial pressure was recorded before withdrawing blood (T0),immediately after the end of withdrawing blood (T1),at 30 min after the end of withdrawing blood (T2),before infusion of the shed blood (T3),and immediately after infusion of the shed blood (T4).The arterial blood samples were obtained at T0,T1,T3 and T4 for blood gas analysis.At 72 h after infusion of the shed blood,6 rats were selected from each group,and cognitive function was assessed by Y-maze test.The animals were then sacrificed,and brains were removed and sliced for determination of the expression of caspase-12 in hippocampal CA1 region by immunohistochemistry.The rest 6 rats in each group were sacrificed at 72 h after infusion of the shed blood,and the hippocampus was isolated for determination of the expression of ATF6 and caspase-12 by Western blot.Results Compared with group S,mean arterial pressure was significantly decreased at T1-3 (P＜0.05),the pH value and base excess were significantly decreased at T1.3,and the blood lactic acid was significantly increased at T1,3 in HSR and SP groups,and the number of total training was significantly increased,the rate of memory retention was significantly decreased,the expression of caspase-12 in hippocampal CA 1 region was significantly up-regulated,and the expression of ATF6 and caspase-12 in hippocampal tissues was significantly up-regulated in group HSR (P＜ 0.05).Compared with group HSR,the number of total training was significantly decreased,the rate of memory retention was significantly increased,the expression of caspase-12 in hippocampal CA1 region was significantly down-regulated,and the expression of ATF6 and caspase-12 in hippocampal tissues was significantly down-regulated in group SP (P＜0.05).Conclusion The mechanism by which sevoflurane postconditioning improves cognitive function is related to down-regulation of ATF6 expression in the brain tissues in a rat model of hemorrhagic shock and resuscitation.
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Objective To investigate the effect of intrathecal morphine preconditioning (ITMP) on the excitability of substantia gelatinosa (SG) neurons in the dorsal horn of the spinal cord in a rat model of myocardial ischemia-reperfusion (I/R).Methods Thirty-six adult male Sprague-Dawley rats,weighing 200-300 g,in which intrathecal catheters were successfully placed without complications,were randomly divided into 3 groups (n =12 each) using a random number table:sham operation group (group S),group I/R,and group ITMP.Myocardial I/R injury was produced by occlusion of the left anterior descending branch of the coronary artery for 30 min followed by 120 min reperfusion.In group ITMP,the rats received intrathecal morphine 3 μg/kg (10 μl) by three cycles of 5 min infusions interspersed with 5 min infusion-free periods starting from 30 min before ischemia,and the equal volume of normal saline was given instead of morphine in group I/R.At 10 min of reperfusion,6 rats randomly selected in each group were sacrificed,and the T2-6 segments of the spinal cords were acutely isolated to prepare spinal cord slices.The resting potential,threshold of action potential (APT),peak of action potential (APP) and action potential duration in SG neurons in the dorsal horn of spinal cord slices were determined using the whole-cell patch-clamp technique,and the number of action potentials evoked by currents of 40,60,80 and 100 pA was recorded.At 120 min of reperfusion,6 rats randomly selected in each group were sacrificed,and myocardial specimens were obtained for determination of myocardial infarct size (IS) and area at risk (AAR),and IS/AAR ratio was calculated.The expression of c-fos in the T2-5 dorsal horns of the spinal cords was detected by Western blot.Results Compared with group S,the IS/AAR ratio was significantly increased,the expression of c-fos was up-regulated,the number of action potentials in SG neurons in dorsal horns of spinal cord was increased,APT was decreased,and APP was increased in group I/R (P＜0.05).Compared with group I/R,the IS/AAR ratio was significantly decreased,the expression of c-fos was down-regulated,the number of action potentials in SG neurons in dorsal horns of spinal cord was decreased,APT was increased,and APP was decreased in group ITMP (P＜0.05).Conclusion The mechanism by which ITMP attenuates myocardial I/R injury is related to decrease in the excitability of SG neurons in the dorsal horn of the spinal cord and reduction of responses to nociceptive stimuli in rats.
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Objective To investigate microRNAs ( miRNAs) expression profiling of cardiomyocytes in rats with heart failure, and predict miRNAs-regulated target genes and their functions.Methods Total of 18 male SD rats weighing 200-220 g were randomly divided into 2 groups:the control group ( CON) and the heart failure group (HF).The rats in HF group were injected by adriamycin via tail vein to induce heart failure, meanwhile in CON group, rats were received an equal volume of 0.9% sodium chloride intravenously.The cardiomyocytes isolated from the rat hearts in two groups and cultured overnight.After that, total RNA was extracted and then subjected to miRNA microarray to screen differentially expressed miRNAs.The reults of microarray were further verified by quantitative real-time PCR ( qRT-PCR ) .The target genes regulated by differentially expressed miRNAs were predicted by the software of Targetscan and miRanda.Bioinformatics analysis was performed to predict the miRNAs-regulated target genes and analyze the enriched gene ontology ( GO) and signaling pathway ( KEGG Pathway) .Results The results of miRNA microarray showed that a total of 37 miRNAs were differentially expressed in HF group as compared to CON group, among which 22 miRNAs were up-regulated and 15 miRNAs were down-regulated (P<0.01, FDR<0.05).The expression of miR-133b-5p (t=14.56, P<0.01), miR-6216 (t=9.32, P<0.01) and let-7e-5p (t=13.92, P<0.01) which were detected by qRT-PCR exhibited the similar tendency of up or down regulation to those shown in microarray results.Bioinformatics analysis indicated that miRNAs-regulated target genes were significantly enriched in 31 GOs (P<0.01, FDR<0.05) and 12 signal pathways (P<0.05, FDR<0.05), among which ubiquitin-proteasome system, MAPK signaling pathway and Toll like siganling pathway exhibited a higher enrichment. Conclusion MiRNA expression profile on cardiomyocytes in rat with adriamycin-induced heart failure was significantly changed.These differentially expressed miRNAs might participate in the process of heart failing by regulating their target genes in rat cardiomyocytes.
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Polymyxin E shows effective treatment of the infection induced by resistant gramnegative bacteria, but its nephrotoxicity severely limits the clinical application of this drug. In this work, methoxypolyethylene glycols 2000 (mPEG2K)-polymyxin E (PME) was synthesized via chemical grafting reaction and had been characterized. The antimicrobial activity and cytotoxicity of mPEG2K-PME in vitro were investigated on Escherichia coli and HK-2 cells, separately. Intra-abdominal infection model was further established in order to study the therapeutic effect and the toxic effect on kidney of mice. The results showed that mPEG2K-PME exhibited significant inhibitory effect on Escherichia coli and had a lower toxicity on HK-2 cells in vitro. At the same time, mPEG2K-PME had a good efficacy in the treatment of Escherichia coli infected mice in vivo. Moreover, nephrotoxicity caused by mPEG2K-PME was significantly reduced compared to free PME. mPEG2K-PME is promising in development of new preparations with high efficiency and low toxicity.
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Objective To evaluate the effect of morphine preconditioning on the expression of miR-133b-Sp and Fas in rat cardiomyocytes subjected to hypoxia/reoxygenation (H/R).Methods Cardiomyocytes were isolated from healthy adult male Sprague-Dawley rats by using Langendorff perfusion.The cells were seeded into 24-well plates or 60 mm diameter dishes and randomly divided into 3 groups (n =24 each) using a random number table:control group (group C),group H/R,and morphine preconditioning group (group MPC).The cells in group C were cultured in normal culture atmosphere.In H/R and MPC groups,the cells were exposed to 95％ N2-5％ CO2 for 90 min followed by 120 min reoxygenation.In group MPC,the cells were cultured for 10 min in serum-free DMEM liquid culture medium containing morphine 1 μmol/L,and then were cultured for 30 min in morphine-free DMEM liquid culture medium before hypoxia.At 120 min of reoxygenation,the cells in 24-well plates were selected to detect the cell viability (by MTT),lactate dehydrogenase (LDH) activity in the culture medium,and cell apoptosis (by Hoechst 33234 staining).Apoptosis rate was calculated.Total RNA and protein were extracted from the cells in 60 mm dishes to detect the expression of miR-133b-5p and Fas mRNA (by quantitative real-time PCR) and Fas protein (by Western blot).Results Compared with C group,the cell viability was significantly decreased,LDH activity and apoptosis rate were increased,the expression of miR-133b-Sp was down-regulated,and the expression of Fas mRNA and protein was up-regulated in H/R group.Compared with H/R group,the cell viability was significantly increased,LDH activity and apoptosis rate were decreased,the expression of miR-133b-5p was up-regulatcd,and the expression of Fas mRNA and protein was down-regulated in MPC group.Conclusion The mechanism by which morphine preconditioning reduces H/R injury to rat cardiomyocytesis related to up-regulation of the expression of miR-133b-Sp and down-regulation of the expression of Fas.