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Aim To explore the role of endoplasmic reticulum stress(ERS) in Astragaloside Ⅳ-induced cardioprotection in H9c2 cardiac cells, and to explore the potential mitochondrial mechanism.Methods Conventional culture was performed of rat heart tissue-derived H9c2 cells.Experiment was randomly divided into the control group, the ERS inducer 2-Deoxy-D-Glucose(2-DG) group, Astragaloside Ⅳ and 2-DG combination group, Astragaloside Ⅳ group.Confocal microscopy was used to observe the changes of TMRE fluorescence intensity so as to confirm the influence of ERS on the mitochondrial potential, and further speculate on the opening of the mitochondrial permeability transition pore(mPTP).Western blot analysis was applied to detect the expressions of ERS proteins GRP 78, GRP 94 and IRE1.Transmission electron microscopy was used to observe the ultrastructure of the cells.Results Different doses of 2-DG could mimic the mPTP opener atractyloside to induce the mPTP opening with the peak at 100 μmol·L-1;Astragaloside Ⅳ significantly reduced 2-DG-induced mPTP opening, the expression of GPR 78, GRP 94 and IRE1 and reduced injury of mitochondria and endoplasmic reticulum.Conclusions Endoplasmic reticulum stress could be induced by 2-DG.Astragaloside ⅳ-induced mitochondrial cardioprotection involves inhibition of the ERS through GRP 78, GRP 94 and IRE1 by prevention of the mPTP opening.
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Aim To explore the role of endoplasmic re-ticulum stress( ERS) in Astragaloside Ⅳ-induced car-dioprotection against ischemia/reperfusion injury in rats. Methods A model of myocardial ischemia 30 min followed by 120 min reperfusion was made by liga-ting coronary artery in male Wistar rats. Rats were di-vided randomly into 4 groups: sham group, ischemia/reperfusion group, ERS inhibitor TUDCA group, As-tragaloside Ⅳgroup. Myocardial samples were collect-ed from the risk zones during ischemia and reperfu-sion, ERS was determined by measuring levels of glu-cose regulated protein 78 ( GRP78 ) , an established marker of ERS with Western blot. Immunofluorescence study was used to test GRP78 intensity with laser scan-ning confocal microscopy, TTC method was used to measure the infarct size,hematoxylin-eosin staining was used to observe the changes of morphological changes of myocardium. Results There was no statistical difference in GRP78 expression during ischemia com-pared to the sham group, but was markedly increased upon reperfusion. Astragaloside Ⅳ could mimic TUD-CA and significantly decreased the GRP78 expression, reduced infarct size and improved the morphology of myocardial tissue with a significant statistical difference compared with the control group ( P<0. 05 ) . Conclu-sions ERS is induced upon reperfusion but not during ischemia in isolated rat hearts. Astragaloside Ⅳ pre-vents myocardial reperfusion injury presumably by the inhibition of ERS.
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Objective To observe the neural protection of 3-n-butylphthalide (NBP) injection in focal cerebral ischemia-reperfusion rats. Methods 160 male Sprague-Dawley rats were randomly divided into sham group (n=10), ischemia-reperfusion group (IR group, n=50), high-dose NBP treatment group (high-dose group, n=50), middle-dose NBP treatment group (middle-dose group, n=25) and low-dose NBP treatment group (low-dose group, n=25). The later 4 groups were occluded the middle cerebral artery for 2 hours and reperfused. The sham group was sacrificed 24 hours after operation, and the other groups at 6, 12, 24, 48 and 72 hours after reperfusion, in which 5 of them were stained with TdT mediated dUTP Nick End Labeling (TUNEL) to observe the neuronal apoptosis, and immunohistochemistry to observe the expression of silent information regulation 2 homolog 1 (SIRT1) and peroxisome proliferator-activated receptorγcoactivator-1α(PGC-1α);the other 5 of sham group, IR group and high-dose group were observed with quantitative real-time PCR of SIRT1 and PGC-1α. Results Compared with the IR group, the number of apoptotic cells decreased and the SIRT1 and PGC-1αpositive cells increased in all NBP groups at each time (F>160.60, P4.13, P<0.01). Conclusion NBP can protect brain from apoptosis in focal cerebral ischemia-reperfusion rats, which may relate to more ex-pression of SIRT1 and PGC-1α.
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Objective To observe the changes of ischemic preconditioning on the expression of hypoxia inducible fac?tor (HIF)-1αand vascular endothelial growth factor (VEGF) in ischemia hippocampus CA1 region after focal cerebral isch?emia/reperfusion (I/R) in rats, and the mechanisms of brain protection from brain ischemia preconditioning (BIP) thereof. Methods The male SD rats were randomly divided into three groups:sham operation (SO) group,middle cerebral artery oc?clusion (MCAO) group and brain ischemia preconditioning (BIP) group. The MCAO group and BIP group were further divid?ed into six subgroups according to perfusion time after I/R including 2 h, 6 h, 12 h, 24 h, 48 h and 72 h. The ischemia pre?conditioning model rats were established. Immunohistochemistry and Western blot assay were used to observe the expres?sions of HIF-1αand VEGF in ischemia hippocampal CA1 region. Results Neurological function deficit was not observed in SO group. Compared with MCAO group, there was a lower neurological function deficit score in BIP group. In MCAO group and BIP group, the expressions of HIF-1αand VEGF positive cells and protein increased at 2 h after I/R, then gradu?ally increased from 6 h to12 h and reached the maximum level at 24 h, then gradually decreased. The levels were still higher at 72 h than those of SO group. The number of HIF-1αand VEGF positive cells and protein were significantly increased in MCAO group and BIP group than that of SO group (P<0.05). The number of HIF-1αpositive cells was higher in BIP group than that in MCAO group except 2 h and 6 h reperfusion groups. The expression of VEGF positive cells, HIF-1αand VEGF protein were significantly higher in BIP group than those in MCAO group at different time points (P < 0.05). Conclusion Ischemic preconditioning plays a protective role in brain, which may be related to up-regulation of HIF-1αand VEGF.
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BACKGROUND:Numerous clinical studies have confirmed that the microenvironment at a spinal cord injury site can be obviously improved through hyperbaric oxygen therapy; however, what effect does hyperbaric oxygen have on the microenvironment of the injured brain? OBJECTIVE:To investigate the effect of hyperbaric oxygen therapy on nerve regeneration microenvironment and the recovery of rat nerve function after focal cerebral infarction. METHODS:Rat models of focal cerebral infarction were established by occlusion of the middle cerebral artery and subjected to hyperbaric oxygen therapy. Sham group and model group were established as comparison. In the sham group, rat models of focal cerebral infarction were established but did not receive any treatment. Rats in the model group were placed in a hyperbaric oxygen therapy chamber but the pressure and oxygen concentration were not administered. RESULTS AND CONCLUSION:Compared with the model group, the score of rat limb function at 16 days after treatment and the expression of growth associated protein 43 in the rat cerebral infarcted area at postoperative 14 days were significantly increased , but infarct volume at postoperative 24 hours was al significantly decreased in the hyperbaric oxygen therapy group (alP < 0.05). These results confirmed that hyperbaric oxygen therapy can improve nerve regeneration microenvironment and promote the recovery of rat nerve function after focal cerebral infarction.
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Objective Cerebral ischemic tolerance induced by cerebral ischemic preconditioning has become a hotspot in the researches of ischemic cerebrovascular disease, and its specific mechanism remains to be clarified.This study was to explore the brain protection mechanisms of cerebral ischemic preconditioning by observing the expressions of HIF-1αand VEGF in the cortex area sur-rounding the infarct locus in rats with focal cerebral ischemia /reperfusion ( I/R) after cerebral ischemic preconditioning. Methods A total of 130 male SD rats were randomly divided into three groups:sham operation, middle cerebral artery occlusion, and cerebral is-chemic preconditioning, the animals in the latter two groups subjected to 2, 6, 12, 24, 48 and 72 h of I/R.The expressions of HIF-1α and VEGF at different time points were detected by immunohistochemistry and Western blot. Results In the middle cerebral artery occlusion group, the expressions of HIF-1αand VEGF positive cells and proteins increased at 2 h after I/R, reached the peak at 24 h, and then gradually decreased to and at 72 h, but still higher than in the sham operation group (P<0.05).The expressions of HIF-1αand VEGF positive cells were significantly higher in the cerebral ischemic preconditioning than in the middle cerebral artery occlusion group (all P<0.05), so were the expressions of HIF-1αand VEGF positive proteins in the former group than in the latter (all P<0.05).The sham operation group showed only a little in-crease in the expressions of HIF-1αand VEGF positive cells and proteins. Conclusion Cerebral ischemia reperfusion injury induces the expressions of HIF-1αand VEGF, which can be further upregulated by brain ischemic preconditioning.
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[Abstract ] Objective The purpose of this study was to observe the effects of dl-3n-butylphthalide (NBP) sodium chloride injection post-processing on the expressions of X-inhibitor of apoptosis (XIAP) and Bcl-2/adenovirus E1B19kDa interacting protein 3 (BNIP3) in the hippocampus CA1 neurons of focal cerebral ischemia reperfusion (IR) rats, and to investigate the brain-protection mechanisms of NBP. Methods A total of65 adult male Sprague-Dawley rats were divided into five groups of equal number, sham op-eration, IR, and low-,medium -and high-dose NBP, according to the random number table. The IR models were established by modified ligation of the middle cerebral artery.The animals in the NBP groups received intra-abdominal injection of NBP at 2, 4, and 6 mg/kg, re-spectively.All the rats were sacrificed at 24 hours after modeling,neurological scores obtained by Zea Longa, the volume of infarction measured by TTC staining, the number of apoptotic cells counted by TUNEL, and the expressions of XIAP and BNIP3 detected by immunohistochemistry and real-time PCR. Results The neural function defect scores were markedly lower in low-, medium-and high-dose NBP groups than in IR model rats (P<0.05), with statis-tically significant differences among the three dose groups (P<0.05).The volume of infarction was remarkably higher in the low-dose than in the medium-and high-dose NBP groups (P<0.05).The number of apoptotic cells in the hippocampus CA1 neurons was de-creased in the NBP groups as compared with the IR models (P<0.05).The XIAP-and BNIP3-positive cells were significantly in-creased in the IR model rats as compared with the sham operation group ([22.31 ±0.94] and [60.13 ±2.59]/HP vs [3.07 ±1.43] and [5.78 ±0.44]/HP, P<0.05).In comparison with the IR models, the NBP-treated rats showed a progressively increased number of XIAP-positive cells in low-, medium-, and high-dose groups ([28.70 ±1.18], [32.79 ±0.88], and [37.01 ±1.24]/HP) (P<0.05) but a decreased number of BNIP3-positive cells in the three dose groups ([52.07 ±1.02], [40.30 ±2.00], and [31.04 ± 0.43]/HP) (P<0.05).Similarly, the expression of XIAP mRNA was up-regulated while that of BNIP3 mRNA down-regulated in the NBP treatment groups as compared with the IR model rats, both in a dose-dependent manner (P<0.05). Conclusion NBP post-processing has a neuroprotective effect on IR rats, which is associated with its impact on the expressions of XIAP and BNIP3.
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BACKGROUND:Studies have shown that human telomerase reverse transcriptase (hTERT) has the ability to enhance cel proliferation, maintain telomere length, prolonged cel life cultured in vitro. OBJECTIVE:To observe the effect of hTERT gene-modified bone marrow mesechymal stem cel transplantation on neural function recovery of rats with cerebral infarction. METHODS:Rat models of middle cerebral artery occlusion were established and randomized into model group, cel transplantation group and hTERT-modified cel transplantation group, with 20 rats in each group. Rats in the three groups were respectively injected via tail vein with 1 mL PBS, passage 9 bone marrow mesenchymal stem cel suspension (2.5×107/L) and hTERT-modified passage 9 bone marrow mesenchymal stem cel suspension (2.5×107/L), respectively. Modified neurological severity scores were determined before and after transplantation; RT-PCR and western blot assay were used to measure hTERT expression at gene and protein levels; TUNEL method was adopted to detect cel apoptosis in the brain. RESULTS AND CONCLUSION:hTERT-modified bone marrow mesenchymal stem cels had prolonged cel cycle, and with the increase in passage number, the cels showed good growth with no changes in morphology. The expressions of hTERT mRNA and protein were superior in the hTERT-modified cel transplantation group than the cel transplantation group, and there was a significant difference (P < 0.05). Modified neurological severity scores and number of apoptotic cels were decreased significantly in the hTERT-modified cel transplantation group compared with the other two groups (P < 0.05). These findings indicate that hTERT-modified bone marrow mesenchymal stem cels can promote neural functional recovery of rats with cerebral infarction.
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OBJECTIVE To explore bacteria distribution and changing status in infectious species from our hospital. METHODS The infectious species were collected from daily work.After bacteria culturing and genus identification by VITEK system,bacteriology data and corresponding clinical data were analyzed. RESULTS From Jan 2001 to Dec 2004,Staphylococcus aureus,S.epidermidis,Escherichia coli,Klebsiella pneumoniae,Pseudomonas aeruginosa and fungi were isolated most frequently in order. CONCLUSIONS Dynamic supervision of causative bacteria of nosocomial infection is strongly recommended.