针刺对缺血再灌注大鼠脑细胞凋亡的保护作用及机制

Objective To investigate the protective effect and mechanisms of acupuncture on the mem-brane potential in mitochondria of the brain cells injury induced by ischemia and reperfusion. Method The mid-dle cerebral artery occlusion/repeffusion (MCAO/R) rat model was established by the modified Longa occlusion method. The Baihui and Shuigou Point in Du meridian was acupunctured electrically 30 min. After reperfusion 24 h and 48 h, mitochondrial membrane potential, apoptosis and mitochondria ultrastrocture of brain cells were detected by the method of Rhodamin123 fluorescence staining,TUNEL in situ labeling and electron microscopy respectively after repeffusion 24 h and 48 h. Results The fluorescence intensity of Rhodamin123 was 961.27±34.22 and 1231.23±121.54 after focal cerebral ischemic reperfusion 24 h and 48 h respectively,this result was increased to compare with sham-operated group. The fluorescence intensity of Rhodamin 123 in group of using the intervention of acupuncture was 808.44±56.23 and 954.25±35.11 after operation 24 h and 48 h respectively ,this values de-creased significantly to compare with the group of ischemic reperfusion. The amount of apoptosis cells after cerebral ischemia reperfusion 24 h and 48 h were more than the sham group. The amount of apoptosis cells after acupuncture was less than the cerebral ischemic reperfusion group. The mitochondrial membrane shown intumesee,disaggrega-tion, endocrista collapsing and toxic granulation increased after ischemie reperfusion and this non-specificity change of mitochondrion alleviated by using acupuncture. Conclusion Acupuncture stabilized the permeability of mitochon-drial membrane, reduced the dissipation of mitochondrial transmembrane potential, decreased the amount of apopto-sis of brain cells of ischemic reperfusion and increased the toleration of brain against the ischemic and anoxie inju-ry. Conclusion Acupuncture could stabilized the permeability of mitochondria membrane. It could decreased the dissipation of cytochondriome transmembrane potential and the amount of apoptosis of brain cells. It could increased the toleration of brain against the ischemic and anoxic injury.     

Myocardial protection with pinacidil induced hyperpolarized arrest during cardiopulmonary bypass

Objective To investigate the myocardial protective effects of pinacidil-induced hyp erpolarized arrest and compare with those afforded by conventional dep olarized hyperkalemic arrest. Methods Eighteen dogs were equally divided into three groups: normothermic hyperpo larized group (Group A), hypothermic hyperpolarized group (Group B), and hyperk a lemic group (Group C). Pinacidil (50 μmol/L) containing 37℃ St . Thomas sol ution (K(+) 5 mmol/L, 10 ml/kg), pinacidil (50 μmol/L, Sigma, USA) containi ng 4℃ St. Thomas solution (K(+) 5 mmol/L, 10 ml/kg) and 4℃ standard St. Thomas solu tion (K(+) 16 mmol/L, 10 ml/kg) were infused respectively through the aortic r oot after aortic-clamping. Heart arrest and its recovery, ultrastruct ure of the myocardium, the level of serum myocardial enzymes, and lipid perox ide and adenine nucleotide of the myocardium were measured. Hemodynamics durin g ischemia and after reperfusion were observed.Results The percentages of normal mitochondria and glycogen did not change much du r ing ischemia (except at 60 min) and after reperfusion in B Group, but declin ed markedly in Group C 30 min and 60 min after ischemia and 20 min after repe rfusion (P<0.01). In Group A, they were lower than those of Group B before ischemia, but higher than those of Group C. The recoveries of CO, SV, CI, LVSW, RVSW and MAP in Group B were significantly better than t hose in other two groups 15 min and 30 min after reperfusion (P<0.05 and 0.01, respectively). However, they were still better in Group A tha n those in Group C (P<0.05 and 0.01, respectively). The onset of he art arrest was faster in Groups C and B than that in Group A . Highly elevated serum myocardial enzymes were observed 60 min after ischem ia and 20 min after reperfusion in Group C, while they were only mild in the hy perpolarized groups, especially in Group B, and their recoveries were rapid. A denine nucleotides of the myocardium were better preserved in Group B than in other two groups 30 min, 60 min after ischemia, and 20 min after reperfusion ( P<0.05 and 0.01, respectively). They were also much better in Gro up A than in Group C (P<0.05 and 0.01, respectively). Lipid pero xide of the myocardium were significantly lower in Group B than in other grou ps 20 min after reperfusion (P<0.01), and they were lower in Group A than in Group C (P<0.05). Conclusions Myocardial protection for global ischemia during cardiopulmonary bypass (CPB) could be achieved with hyperpolarized heart arrest induced by pi nacidil, an ATP- sensitive potassium channel opener, especially in the hypothermic state. The protection is weaker in normothermia but is stil l superior to that with traditional depolarized hyperkalemic arrest.     

Effect of propentofylline on hypoxic-ischaemic brain damage in newborn rat

Background Studies showed that propentofylline enhances the action of adenosine and protects hippocampal neuronal demage against transient global cerebral ischaemia. Our study was to investigate the effect of propentofylline on hypoxic-ischaemic brain damage in neonatal rat.Methods Seven-day-old Wistar rats were subjected to unilateral common carotid artery ligation and hypoxia in oxygen 8 kPa for two hours at 37℃. Propentofylline (10 mg/kg) was administered intraperitoneally one hour after hypoxia-ischaemia (treated group). Control group rats were received an equivalent volume of saline. The effects of propentofylline were assessed by observing the body mass gain, behavioural alteration and neurohistological changes. The rats were sacrificed at 72 hours after hypoxia-ischaemia, and the brain sections were examined after haematoxylin and eosin staining.Results The propentofylline-treated rats had better body mass gain and better behavioural response than the paired saline-controls did. In the control group, the rats either lost body mass or had little mass gain after the insult, their average body mass gain was 97.3% at 24 h, 100.3% at 48 h, and 114.1% at 72 h of recovery. In propentofylline-treated group, there was a significant improvement of body mass gain at 24 h (100.2%, P<0.05) and 48 h (110.3%, P<0.01) of recovery; the percentage of rats that performed well on behavioural test was significantly higher from 48 h to 72 h of recovery (P<0.05); the incidence of severe brain damage to the cerebral cortex and dentate gyrus was significantly reduced in propentofylline-treated rats (cortex, 93%-70.8%, P<0.01; dentate gyrus 95%-66.7%, P<0.01) as compared with control rats. Conclusions Administration of propentofylline 1 hour after hypoxia-ischaemia significantly attenuates brain damage in both the cerebral cortex and dentate gyrus, and also improves the body mass gain as well as behavioural disturbance in 7-day-old rats.     

Clinical pathological study of treatment of chronic hepatitis with hyperbaric oxygenation

Objective To detect the feasibility and theoretic basis for treatment with hyperbaric oxygenation (HBO) in chronic hepatitis and to compare the changes in hepatic function, immunity, pathologic morphology, ultrastructure and HBV in hepatic tissues before and after treatment. Methods Sixty cases of chronic hepatitis were randomly selected and divided into two groups: the experiment (n=30) and control groups (n=30). Patients in the experimental group were treated with HBO for 6 courses. Patients in the control group were treated for 60 days with the usual drugs used in the clinic. The function and bloodstream graph of liver were examined and liver biopsies were made before and after treatments. Routine paraffin sections were stained with HE and observed under the light microscope. Ultra thin slides from paraformaldehyde and glutaraldehyde fixed liver tissue were stained with lead citrate and observed with the transmission electric microscope. HBsAg and HBcAg in liver of the experimental group were detected with ABC immunohistochemistry method before and after treatment. Results For the experimental group, ALT, SB, γ-GT, AKP, IgG, and IgM in blood and the degeneration and necrosis of hepatocytes were remarkably decreased (P<0.05), the mean contractive wave of bloodstream in liver and the bloodstream in right ramus of janitrix were remarkably increased (P<0.05), and the swelling of mitochondria, increase of lysosomes, generation of Kupffer cells, infiltration of lymphocytes in portal area and capillary generation were all remarkably alleviated (P<0.05) after treatment with HBO. There were significant differences between the experimental and control groups after treatment with different methods (P<0.05). For patients in the experimental group, the fibrosis and fat-storing cells in the liver were not reduced (P>0.05), and the expression of HBsAg and HBcAg in liver was not weakened (P<0.05) after treatment. Conclusions Treatment with HBO for chronic hepatitis was effective and recommendable, but it could not reverse liver fibrosis. However, it might be able to delay or prevent the liver from fibrosis, so it might be more effective at the early and middle stages of chronic hepatitis. HBO could not inhibit the HB virus. So we consider that treatment with HBO should be simultaneous with anti HBV therapy.     

Clinical Observation on 30 Cases of Transient Cerebral Ischemia Attack Treated with Acupuncture and Medication

Objective: To probe the curative effect of acupuncture and medication on transient cerebral ischemia attack. Method: 30 patients with transient cerebral ischemia attack in the treatment group were acupunctured at Fengchi (GB 20), Wangu (GB 12) and Tianzhu (BL 10) and given orally leech capsules and centipede capsules. 30 patients with transient cerebral ischemia attack in the control group were given intravenous drip of compound Danshen injection and orally aspirin. At the end of two treatment courses, the curative effects were evaluated and the changes in blood rheology and in 3 indexes of blood coagulation were observed before and after treatment in the 2 groups. Results: The total effective rate in the treatment group was 86.7% with obvious difference as compared to the control group (P<0.05). There were remarkable differences in blood rheology and 3 indexes of blood coagulation before and after treatment in the treatment group (P<0.05, P<0.01). There were remarkable differences after treatment between the 2 groups (P<0.05). Conclusion: Acupuncture at Fengchi (GB 20), Wangu (GB 12) and Tianzhu (BL 10) and medication with leech capsules and centipede capsules are effective methods in treating transient cerebral ischemia attack.     

Effect of mitochondrial KATP channel on voltage-gated K+ channel in 24 hour-hypoxic human pulmonary artery smooth muscle cells

Background Hypoxic pulmonary hypertension (HPH) is initiated by inhibition of O2-sensitive, voltage-gated (Kv) channels in pulmonary arterial smooth muscle cells (PASMCs). The mechanism of hypoxic pulmonary hypertension has not yet been fully elucidated. The mitochondrial ATP-sensitive K+ channel (MitoKATP) is extremely sensitive to hypoxia, and is a decisive factor in the control of mitochondrial membrane potential (ΔΨm). This study investigated the changes of cell membrane potential and Kv channel in cultured human pulmonary artery smooth muscle cell (hPASMC) exposed to 24 hour-hypoxia, and explored the role of MitoKATP and ΔΨm in this condition. Methods Fresh human lung tissues were obtained from the patients undergoing a chest operation. hPASMCs were isolated, cultured, and divided into 6 groups: ① control group, cultured under normoxia; ② diazoxide group, cultured in normoxia with diazoxide, an opener of MitoKATP; ③ 5-HD group, cultured in normoxia with sodium 5-hydroxydecanoate (5-HD), an antagonist of MitoKATP; ④ 24 hour-hypoxia group; ⑤ 24 hour-hypoxia + diazoxide group; and ⑥ 24 hour-hypoxia + 5HD group. Whole-cell patch-clamp technique was used to trace the cell membrane K+ currents. The expressions of cell membrane Kv1.5 mRNA and protein were determined by RT-PCR and Western blot technique, respectively. The relative changes in mitochondrial potential were tested with rhodamine fluorescence (R-123) technique. Results After exposure to diazoxide for 24 hours, the intensity of R-123 fluorescence in normoxic hPASMCs was significantly increased compared with control group (P&lt;0.05), but there were no significant changes in these tests after the hPASMCs had been exposed to 5-HD for 24 hours. Twenty-four hour-hypoxia or 24 hour-hypoxia + diazoxide could markedly increase the intensity of R-123 fluorescence in hPASMC and the changes were more significant in 24 hour-hypoxia +diazoxide group than in 24 hour-hypoxia group (P&lt;0.05) although 5-HD could partly weaken the effect of 24 hour-hypoxia on the intensity of R-123 fluorescence. After exposure to diazoxide for 24 hours, the cell membrane K+ currents and the expression of cell membrane Kv1.5 mRNA and protein in normoxic hPASMCs were significantly decreased compared with control group (P&lt;0.05), but there were no significant changes in these tests after the hPASMCs had been exposed to 5-HD for 24 hours. Also, 24 hour-hypoxia or 24 hour-hypoxia + diazoxide decreased the cell membrane K+ currents and the expression of Kv1.5 mRNA and protein (P&lt;0.05) but the changes were more significant in 24 hour-hypoxia + diazoxide group than in 24 hour-hypoxia group (P&lt;0.05). Again, 5-HD could partly weaken the inhibitory effect of 24 hour-hypoxia on the cell membrane K+ currents and the expression of Kv1.5 mRNA or protein (P&lt;0.05). Conclusions The opening of MitoKATP followed by a depolarization of ΔΨm in hypoxia might contribute to the alterations in the expression of cell membrane Kv1.5 mRNA and protein leading to change in the cell membrane potential of hypoxic hPASMCs. This might be a mechanism of the development of hypoxic pulmonary hypertension.     

Comparative study of D2 receptors and dopamine content in striatum before and after electro-acupuncture treatment in rats

Objective To evaluate the change in D(2) receptors and their relationship with dopamine (DA) content in experimental hemi-parkinsonism rats before and after electro-acupuncture (EA) treatment. Methods (125) Ⅰ-IBZM D(2) receptor cerebral autoradio-graphic analysis, HPLC-ECD detection of DA and its metabolites, homovanillic acid (HVA), 3,4-dihydroxyphenylacetic acid (DOPAC) were used to study their levels in striatum in pre-EA, EA and EA control group. Results The DA, HVA and DOPAC levels in striatum of the lesioned side in the EA group were elevated compared to the pre-EA and EA control group (P&lt;0.05). For the EA group, the striatum/cerebellum (125) Ⅰ-IBZM uptake ratio of the lesioned side was 8.04±0.71, (29.34%±4.83%) more than that of the contralateral side (P&lt;0.05), while no significant difference was observed as compared with that in the pre-EA group (8.09±0.52, 30.12%±4.53%, higher than that of the intact side P&gt;0.05). It was lower than the EA control group (8.61±0.63, P&lt;0.05), and the latter was (38.63%±3.71%) higher than that in its contralateral side (P&lt;0.05). Conclusion 6-OH-DA lesions in the substantia nigra and ventral tegmental areas induce an up-regulation of striatal D(2) binding sites. EA treatment could elevate the DA level of the lesioned side striatum and prevent D(2) receptor up-regulation in rats with experimental hemi-parkinsonism.     

Clinical, brain electric earth map, endothelin and transcranial ultrasonic Doppler findings after hyperbaric oxygen treatment for severe brain injury

Objective　To analyze the effect and mechanism of hyperbaric oxygen (HBO) treatment for severe brain injury (SBI). Methods　Fifty-five patients were divided into a treatment group of 35 patients and a control group of 20 patients. We observed the alterations of clinical, brain electric earth map (BEAM), endothelin (ET) and transcranial ultrasonic Doppler (TCD) findings before and after HBO treatment as well as outcome. Results　In the treatment group, Glasgow coma scale, BEAM and outcome improved after HBO treatment; compared with that of the control group, it showed a significant difference. After one course of treatment, treatment group ET was reduced from 91.24±12.18?ng/L to 68.88±14.37?ng/L (P&lt;0.01); in control group, ET was reduced from 90.78±15.71?ng/L to 83.12±12.22?ng/L, with a statistically significant difference (P&lt;0.05). TCD records of MCA mean velocity (Vm) was reduced from 64.2±4.8?cm/s to 51.6±4.2?cm/s (P&lt;0.01), and a decrease in MCA systolic velocity (Vs) and pulse index (PI) values was statistically significant (P&lt;0.01). Conclusion　HBO treatment can improve the clinical, BEAM and outcome of severely brain injured patients, by decreasing acute stage ET and improving the blood velocity of MCA and decreasing cerebral vascular resistance. HBO treatment can reduce cerebral vascular spasms, cerebral ischemia and hypoxia. One of the important mechanisms of HBO treatment for severe brain injury is the lowering of intracranial pressure.     

Real-time myocardial contrast echocardiography can predict functional recovery and left ventricular remodeling after revascularization in patients with ischemic heart disease

Background Previous studies showed that preservation of microvascular integrity after myocardial ischemia was associated with myocardial viability. Real-time myocardial contrast echocardiography (RT-MCE) is a promising modality for non-invasive evaluation of microcirculation perfusion. Thus, it provides a unique tool to detect myocardial viability. We sought in this study to investigate the role of RT-MCE in predicting left ventricular (LV) functional recovery and remodeling after revascularization in patients with ischemic heart disease.Methods Thirty-one patients with ischemic heart disease and resting regional LV dysfunction were included. LV volume, global and regional function were evaluated by echocardiography before and 6&#8722;9 months after revascularization. RT-MCE was performed before revascularization using low mechanical index power modulation imaging. Myocardial contrast opacification of dysfunctional segments was scored on a 3-point scale and mean contrast score in dysfunctional segments was calculated. Patients were divided into 2 groups according to mean contrast score in dysfunctional segments: group A, patients with mean contrast score ≥0.5 (n=19); group B, patients with mean contrast score &lt; 0.5 (n=12). Results Wall motion improvement was found to be 94.5%, 45.5% and 16.1% respectively (P&lt;0.01) in homogenous, patchy and absent contrast opacification segments. At baseline, there was no significant difference in LV volume and global function between the two groups. After revascularization, group B had significantly larger LV end-diastolic volume (LVEDV) and LV end-systolic volume (LVESV), lower LV ejection fraction (LVEF) and higher wall motion score index (WMSI) than those of group A (all P&lt;0.05). Revascularization was followed by significant improvement of LV volume and recovery of global LV function in group A (all P&lt;0.01); however, in group B, after revascularization, deterioration of LVEDV (P&lt;0.05) was observed, moreover LVESV, WMSI and LVEF did not change significantly.Conclusions The maintenance of myocardial microcirculation detected by RT-MCE can predict functional recovery and LV remodeling after revascularization in patients with ischemic heart disease, which might be helpful in clinical decision-making and risk stratification.     

Cardioprotective effects of morphine on rat heart suffering from ischemia and reperfusion

Objective To investigate the cardioprotective effects of morphine on ischemic reperfused rat heart in vitro and its mechanism.Methods The isolated rat heart was perfused in a Langendorff apparatus. Infarct myocardium was determined by TTC. Coronary flow (CF), heart rate (HR), left ventricular pressure (LVP), the first derivative of ventricular pressure (LVP/dtmax) and infarct size after ischemia and reperfusion in rat heart given 0.3 μmol/L morphine were observed. The effects of naloxone and glibenclamide on the cardioprotection of morphine were also measured.Results After ischemia and reperfusion, CF, HR, LVP and LVP/dtmax of isolated rat hearts decreased significantly (P&lt;0.01). After morphine preconditioning, HR, LVP and LVP/dtmax increased (P&lt;0.01) and infarct size was reduced significantly (P&lt;0.01), while no significant change in CF (P&gt;0.05). The cardioprotective effects of morphine were abolished by naloxone or glibenclamide completely.Conclusions Morphine can reduce ischemia-reperfusion injuries in isolated rat heart. The cardioprotective effects of morphine are mediated by a local opioid receptor-KATP channel linked mechanism in rat hearts.     

生物波调控因子对脑缺血保护作用的研究

目的：研究生物波调控因子对脑缺血后再灌流脑细胞线粒体有无保护作用。方法：通过大鼠四血管闭塞（热灼两侧椎动脉、夹闭两侧颈总动脉）造成脑缺血和再灌流的动物模型，提吨脑组织匀浆中线粒体并用丙酮酸钠及苹果酸钠作底物，测定脑细胞线粒体的呼吸三态，四态和呼吸控制率。结果：脑缺血２０ｍｉｎ组和缺血２０ｍｉｎ后再灌流４ｄ组大鼠脑线粒体呼吸功能与假手术组相比差异非常显著，特别是呼吸控制率的降低非常明显；而用生物波调     

银杏内酯B对局灶性脑缺血时星形胶质细胞GFAP表达的影响

目的 观察血小板活化因子(PAF)受体拮抗剂银杏内酯B(GB)对局灶性脑缺血时星形胶质细胞胶质纤维酸性蛋白(GFAP)表达的影响,并探讨其作用机制.方法 建立光化学诱导树局灶性脑缺血模型,用HE染色和电镜技术观察缺血后不同时间脑组织星形胶质细胞的形态学改变;用免疫组织化学法观察脑缺血后4 h、24 h、72 h及给予GB后24 h半暗区及对侧皮层星形胶质细胞GFAP的表达,并测定其平均灰度值.结果 光镜下可见,HE染色显示树局灶性脑缺血后,随缺血时间延长,星形胶质细胞形态有不同程度改变;电镜观察显示缺血24 h时星形胶质细胞明显肿胀.免疫组织化学染色可见,半暗区星形胶质细胞GFAP表达在4 h时没有明显改变, 24 h时增加 (P＜0.01),72 h时仍维持在较高水平(P＜0.01);对侧皮层星形胶质细胞GFAP表达于72 h时开始增加(P＜0.05).缺血后6 h舌下静脉注射GB至缺血24 h时,星形胶质细胞GFAP表达少于缺血组(P＜0.05),但仍较假手术组高.结论 脑缺血后星形胶质细胞GFAP表达增强,GB可通过减少星形胶质细胞GFAP的表达而起脑保护作用.     

Endogenous nitric oxide on mitochondrial oxygen consumption after cerebral ischemic reperfusion

Braintissueisrathersensitivetoischemiaandanoxia.Itmaybefurtherdamagedafterreperfusion.Anumberofstudiesaboutpathologicmechanismhavebeenmade.EndogenousNOisanewkindofneurotransmitterandisnotedintherecentdecade:l3j.ItalsoshowscytoxiceffectwhenNOisoverproduced.WehavemadeanexperimentonthechangeofmltochondriaoxygenconsumptionstatustoexploretheeffectofendogenousNOafterischemicreperfusion.Thepresentstudywillprovideuswithmoreevidencetodescribethemechanismofcerebralischemicreperfusioninjury.MATERIA…     

血栓性脑缺血树鼩海马灌流液与动脉血液气体和酸碱度变化的研究

目的：检测血栓性脑缺血后海马灌流液和血液中气体及酸碱度变化并探讨其相互关系。方法：建立光化学诱导树鼩血栓性脑缺血模型，进行海马微灌流收集灌流液，同时经颈动脉插管取血，通过IL-1306型血气分析仪检测pH，PCO2，PO2和HCO3ˉ的变化。结果：脑缺血组中动脉血和灌流液的PO2均低于对照组，动脉血PO2平均值比对照组下降1．81 kPa(P＜0．01)，灌流液PO2下降4．17 kPa(P＜0．01)；血PCO2平均值比对照组升高0．87 kPa(P＜0．01)，灌流液PCO2变化不明显(P＞0．05)；血HCO3ˉ下降4．44mmol／L(P＜0．01)，灌流液中则下降6．62mmol／L(P＜0．01)。结论：局灶性脑缺血后，动脉血及海马灌流液均处于低氧状态并伴有不同程度、类型的酸碱平衡失调，血及脑细胞间液酸碱度的测定对伴有海马损伤的缺血性脑病防治具有重要意义。     

低表达NADH脱氢酶[辅酶Q]铁硫蛋白4对乳鼠心肌细胞线粒体功能的影响

目的 探讨低表达NADH脱氢酶[辅酶Q]铁硫蛋白4(NDUFS4)蛋白对乳鼠心肌细胞线粒体功能的影响.方法 通过原代培养30只乳鼠心肌细胞,将培养出的心肌细胞80盘简单随机分为siRNA处理组和对照组,每组40盘细胞.siRNA处理组:在乳鼠心肌细胞上转染NDUFS4 siRNA;对照组:在乳鼠心肌细胞上转染无义siRNA.继续培养48 h后,比较两组细胞在NDUFS4蛋白的表达、线粒体膜电位、细胞活性氧簇(ROS)水平、线粒体钙离子摄取能力和线粒体呼吸控制率上的差异.结果 乳鼠心肌细胞NDUFS4蛋白表达处理组较对照组下调73.58％(P＜0.001),线粒体的膜电位处理组较对照组下降20.49％ (P＜0.05),同时ROS水平处理组较对照组上升32.11％(P＜0.001).乳鼠心肌细胞线粒体钙离子摄取能力处理组较对照组降低33.33％ (P ＜0.001),细胞最大呼吸速率处理组较对照组下降29.18％ (P ＜0.05).结论 NDUFS4在乳鼠心肌细胞线粒体中维持膜电位、ROS的生成、MPTP的开放和能量供应等过程中发挥着重要的功能.     

胰岛素样生长因子-1对大鼠局灶性脑缺血再灌注后神经细胞凋亡及Bcl-2,Bax蛋白表达的影响

目的研究胰岛素样生长因子-1(IGF-1)对大鼠局灶性脑缺血再灌注后神经细胞凋亡及Bcl-2,Bax蛋白表达的影响,探讨IGF-1对脑缺血再灌注损伤的保护作用机制.方法制作大鼠大脑中动脉缺血再灌注模型.30只Wistar雄性大鼠被随机分为假手术组、缺血组及IGF-1治疗组.于缺血10min后经尾静脉给予IGF-1 10μg,应用TTC染色观察梗死灶体积,应用免疫组化染色和TUNEL法检测Bcl-2,Bax蛋白表达及神经凋亡细胞.结果与缺血组比较,IGF-1治疗组梗死体积明显减少(P＜0.01),凋亡细胞数明显减少(P＜0.01),Bcl-2蛋白表达明显升高(P＜0.01),Bax蛋白表达明显降低(P＜0.01).结论IGF-1通过增加Bcl-2蛋白表达,减少Bax蛋白表达,减少神经细胞凋亡,对脑缺血再灌注损伤起保护作用.     

Effects of immediate and delayed mild hypothermia on endogenous antioxidant enzymes and energy metabolites following global cerebral ischemia

Background  The optimal time window for the administration of hypothermia following cerebral ischemia has been studied for decades, with disparity outcomes. In this study, the efficacy of mild brain hypothermia beginning at different time intervals on brain endogenous antioxidant enzyme and energy metabolites was investigated in a model of global cerebral ischemia.

Methods  Forty-eight male Sprague-Dawley rats were divided into a sham-operated group, a normothermia (37°C–38°C) ischemic group and a mild hypothermic (31°C–32°C) ischemia groups. Rats in the last group were subdivided into four groups: 240 minutes of hypothermia, 30 minutes of normothermia plus 210 minutes of hypothermia, 60 minutes of normothermia plus 180 minutes of hypothermia and 90 minutes of normothermia plus 150 minutes of hypothermia (n=8). Global cerebral ischemia was established using the Pulsinelli four-vessel occlusion model for 20 minutes and mild hypothermia was applied after 20 minutes of ischemia. Brain tissue was collected following 20 minutes of cerebral ischemia and 240 minutes of reperfusion, and used to measure the levels of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), reduced glutathione (GSH) and adenosine triphosphate (ATP).

Results  Mild hypothermia that was started within 0 to 60 minutes delayed the consumption of SOD, GSH-Px, GSH, and ATP (P <0.05 or P <0.01) in ischemic tissue, as compared to a normothermic ischemia group. In contrast, mild hypothermia beginning at 90 minutes had little effect on the levels of SOD, GSH-Px, GSH, and ATP (P >0.05).

Conclusions  Postischemic mild brain hypothermia can significantly delay the consumption of endogenous antioxidant enzymes and energy metabolites, which are critical to the process of cerebral protection by mild hypothermia. These results show that mild hypothermia limits ischemic injury if started within 60 minutes, but loses its protective effects when delayed until 90 minutes following cerebral ischemia.

     

鸟氨酸脱羧酶抑制剂减轻猫区域性脑缺血损害的实验研究

采用猫区域性脑缺血模型，在缺血前经静脉给动物注射鸟氨酸脱羧酶（ＯＤＣ）的特异抑制剂双氟甲基鸟氨酸（ＤＦＭＯ）。在右侧大脑中动脉（ＭＣＡ）血流阻断８ｈ之后，测定结果显示动物右侧严重缺血区的脑组织水肿明显减轻，局部脑组织血流量（ｒＣＢＦ）得到改善。脑缺血后血脑屏障损害定量研究（伊文思蓝染色）也表现出ＤＦＭＯ对缺血脑组织具有明显保护作用。     

针刺对缺血再灌注大鼠脑细胞凋亡的保护作用及机制

目的 探讨脑缺血再灌注后针刺对脑细胞线粒体跨膜电位的保护作用及保护机制.方法 采用线栓法制备大鼠局灶性脑缺血再灌注模型,针刺水沟、百会二穴,通过Rhodamin123荧光染色、TUNEL原位标记及电镜观察,分别于脑缺血再灌注后24h及48h检测脑细胞线粒体跨膜电位、线粒体超微结构及脑凋亡细胞的变化.结果 脑缺血再灌注后Rhodamin123的荧光强度增强,术后24h是(961.27±34.22),48h是(1231.23±121.54),与假手术组(782.82±57.24)比较明显增高(P<0.05);针刺干预后Rhodamin123的荧光强度术后24h是(808.44±56.23),48 h是(954.25±35.11),与脑缺血再灌注组比较明显下降(P<0.05);脑缺血再灌注后24h凋亡细胞是[(26.12±2.75)个/视野],48 h凋亡细胞是[(41.24±4.73)个/视野],与假手术组[(3.56±0.92)个/视野]比较明显增加(P<0.05),针刺干预后24h[(19.88±3.32)个/视野]与48 h[(33.23±3.81)个/视野]凋亡细胞数量与脑缺血再灌注组比较明显减少(P< 0.05);脑缺血再灌注后线粒体膜肿胀、崩解,内嵴断裂,中毒颗粒增加,针刺干预后线粒体的非特异性改变明显减轻.结论 针刺能够稳定线粒体膜的通透性,减少线粒体跨膜电位的耗散,减少缺血再灌注后脑细胞凋亡,增加脑组织对缺血缺氧的耐受性.     

大鼠脊髓损伤后局部线粒体呼吸功能的变化

目的:探讨甲基强的松龙对大鼠脊髓损伤后局部线粒体呼吸功能的影响。方法:54只SD大鼠,随机分组为:假手术(对照组)、脊髓损伤(SCI组)和甲基强的松龙治疗(MP组),每组又分为处理后6h、12h、24h三个时相组,每组6只,采用Allen's打击法造成脊髓损伤模型,在各时相提取伤段脊髓线粒体,测定线粒体呼吸Ⅲ态(R3)、Ⅳ态(R4)、呼吸控制率(RCR)、磷氧比(P/O)。结果:SCI组在伤后6h、12h和24h的R3、RCR和P/O显著低于对照组,R4显著高于对照组,有统计学意义(P<0.01);MP组伤后6h和12hR3、RCR和P/O高于SCI组,R4低于SCI组,有统计学意义(P<0.01);MP组R3、R4和RCR在6h和12h时相与对照组之间无明显差异,24h时相R3、RCR和P/O低于正常对照组,有显著差异(P<0.05)。结论:脊髓损伤后局部线粒体呼吸功能明显受到影响,线粒体内膜通透性增加,线粒体氧化磷酸化的偶联程度明显受到抑制。早期使用甲基强的松龙可明显改善线粒体的呼吸功能,保护伤段脊髓线粒体的稳定性。