Temporal pattern of Toll-like receptor 9 upregulation in neurons and glial cells following cerebral ischemia reperfusion in mice

Purpose: The family of Toll-like receptors (TLRs) has recently been reported to play a role in ischemic injury, but the time course and cell types of the post-stroke TLR9 upregulation remain unclear. In this study, we investigated the dynamic changes of TLR9 expression and the expression of TLR9 in neurons and glial cells after cerebral ischemia reperfusion in mice. Methods: Focal cerebral ischemia was induced by middle cerebral artery occlusion for 90 min in male C57BL/6 mice. The TLR9 expression levels in the tissue surrounding the infarct were detected by Western Blot at 6 h, 3 d, 7 d, 14 d, 21 d, and 28 d after reperfusion. The expression of TLR9 in neurons and glial cells was observed by immunofluorescence staining. Results: The expression of TLR9 protein first increased and then decreased, with the peak observed at 14 d–21 d. Only small punctate intracellular TLR9 was occasionally observed in the neurons at each time point, and the TLR9-positive rate showed no difference at different time points. By contrast, the activated microglia gathered at the margin of the infarct, and the intracellular TLR9 changed from scattered small punctate to coarse and lumpy. The TLR9-positive rate of microglia was first increased and then decreased with time, with the peak observed at 3 d. No positive TLR9 staining was found in the astrocytes and oligodendrocytes. Conclusions: TLR9 expression showed dynamic changes for a long period of time and microglias were the main brain cells to express TLR9 after cerebral ischemia and reperfusion.     

Neuroprotective effect ofShenqi Fuzheng injection pretreatment in aged rats with cerebral ischemia/reperfusion injury

Shenqi Fuzheng injection is extracted from the Chinese herbs Radix Astragali and Radix Codonopsis. The aim of the present study was to investigate the neuroprotective effects of Shenqi Fuzheng injection in cerebral ischemia and reperfusion. Aged rats(20–22 months) were divided into three groups: sham, model, and treatment. Shenqi Fuzheng injection or saline(40 m L/kg) was injected into the tail vein daily for 1 week, after which a cerebral ischemia/reperfusion injury model was established. Compared with model rats that received saline, rats in the treatment group had smaller infarct volumes, lower brain water and malondialdehyde content, lower brain Ca2+ levels, lower activities of serum lactate dehydrogenase and creatine kinase, and higher superoxide dismutase activity. In addition, the treatment group showed less damage to the brain tissue ultrastructure and better neurological function. Our findings indicate that Shenqi Fuzheng injection exerts neuroprotective effects in aged rats with cerebral ischemia/reperfusion injury, and that the underlying mechanism relies on oxygen free radical scavenging and inhibition of brain Ca2+ accumulation.     

Neuroprotective effect of Cerebralcare Granule after cerebral ischemia/reperfusion injury

Cerebralcare Granule(CG) improves cerebral microcirculation and relieves vasospasm,but studies investigating its therapeutic effect on cerebral ischemia/reperfusion injury are lacking.In the present study,we administered CG(0.3,0.1 and 0.03 g/m L intragastrically) to rats for 7 consecutive days.We then performed transient occlusion of the middle cerebral artery,followed by reperfusion,and administered CG daily for a further 3 or 7 days.Compared with no treatment,high-dose CG markedly improved neurological function assessed using the Bederson and Garcia scales.At 3 days,animals in the high-dose CG group had smaller infarct volumes,greater interleukin-10 expression,and fewer interleukin-1β-immunoreactive cells than those in the untreated model group.Furthermore,at 7 days,high-dose CG-treated rats had more vascular endothelial growth factor-immunoreactive cells,elevated angiopoietin-1 and vascular endothelial growth factor expression,and improved blood coagulation and flow indices compared with untreated model animals.These results suggest that CG exerts specific neuroprotective effects against cerebral ischemia/reperfusion injury.     

Radix Ilicis Pubescentis total flavonoids combined with mobilization of bone marrow stem cells to protect against cerebral ischemia/reperfusion injury

Previous studies have shown that Radix Ilicis Pubescentis total flavonoids have a neuroprotective effect, but it remains unclear whether Radix Ilicis Pubescentis total flavonoids have a synergistic effect with the recombinant human granulocyte colony stimulating factor-mobilized bone marrow stem cell transplantation on cerebral ischemia/reperfusion injury. Rat ischemia models were administered 0.3, 0.15 and 0.075 g/kg Radix Ilicis Pubescentis total flavonoids from 3 days before modeling to 2 days after injury. Results showed that Radix Ilicis Pubescentis total flavonoids could reduce pathological injury in rats with cerebral ischemia/reperfusion injury. The number of Nissl bodies increased, Bax protein expression decreased, Bcl-2 protein expression increased and the number of CD34-positive cells increased. Therefore, Radix Ilicis Pubescentis total flavonoids can improve the bone marrow stem cell mobilization effect, enhance the anti-apoptotic ability of nerve cells, and have a neuroprotective effect on cerebral ischemia/reperfusion injury in rats.     

Large-conductance Ca2+-activated K+ channel involvement in suppression of cerebral ischemia/reperfusion injury after electroacupuncture atShuigou (GV26) acupoint in rats

Excess activation and expression of large-conductance Ca2+-activated K+ channels (BKCa channels) may be an important mechanism for delayed neuronal death after cerebral ischemia/reperfusion injury. Electroacupuncture can regulate BKCa channels after cerebral ischemia/reperfusion injury, but the precise mechanism remains unclear. In this study, we established a rat model of cerebral ischemia/reperfusion injury. Model rats received electroacupuncture of 1 mA and 2 Hz atShuigou (GV26) for 10 minutes, once every 12 hours for a total of six times in 72 hours. We found that in cerebral ischemia/reperfusion injury rats, ischemic changes in the cerebral cortex were mitigated after electroacupuncture. Moreover, BKCa channel protein and mRNA expression were reduced in the cerebral cortex and neurological function noticeably improved. These changes did not occur after electroacupuncture at a non-acupoint (5 mm lateral to the left side of Shuigou). Thus, our ifndings indicate that electroacupuncture atShuigou improves neurological function in rats following cerebral ischemia/reperfu-sion injury, and may be associated with down-regulation of BKCa channel protein and mRNA expression. Additionally, our results suggest that theShuigou acupoint has functional speciifcity.     

Bone marrow mesenchymal stem cell therapy in ischemic stroke：mechanisms of action and treatment optimization strategies

Animal and clinical studies have conifrmed the therapeutic effect of bone marrow mesenchymal stem cells on cerebral ischemia, but their mechanisms of action remain poorly understood. Here, we summarize the transplantation approaches, directional migration, differentiation, replacement, neural circuit reconstruction, angiogenesis, neurotrophic factor secretion, apoptosis, immunomodulation, multiple mechanisms of action, and optimization strategies for bone marrow mesenchymal stem cells in the treatment of ischemic stroke. We also explore the safety of bone marrow mesenchymal stem cell transplantation and conclude that bone marrow mesenchymal stem cell transplantation is an important direction for future treatment of cerebral ischemia. Determining the optimal timing and dose for the transplantation are important directions for future research.     

牛磺酸对心肌缺血／再灌注损伤的保护作用及机制探讨

离体大鼠心脏灌流模型的实验表明，牛磺酸除明显减轻再灌注心肌的钙超载和脂质过氧化外，还显著改善心肌肌浆网（ＳＲ）的钙转运功能，牛磺酸使肌浆网的钙─三磷酸腺苷酶活性较缺血／再灌注组升高１．１１倍，摄钙初速率和最大摄钙量分别升高６１．７±１．１％和４０．９±６．４％。牛磺酸可直接拮抗氧自由基灌流导致的心肌细胞和ＳＲ的损伤，对离休ＳＲ无直接作用，对心肌局部的肾素─血管紧张素系统也未见有影响。研究结果显示，牛磺酸的心肌保护作用还与其降低再灌注时心肌的脂质过氧化有关。     

醒脑静注射液对实验性脑缺血-再灌注损伤中一氧化氮和内皮素水平的影响

目的 :探讨醒脑静注射液 (XNJI)对脑缺血再灌注损伤 (CIRI)家兔一氧化氮 (NO)和内皮素 (ET)水平的影响。方法 :采用“四动脉闭塞法”制备家兔 CIRI模型 ,随机分为假手术对照组 (A组 )、脑缺血再灌注组(B组 )和脑缺血再灌注加 XNJI治疗组 (C组 )。分别在脑缺血前、缺血 30分钟及再灌注 30、6 0和 12 0分钟不同时间点 ,检测血浆及脑组织 NO浓度和 ET含量。结果 :脑缺血再灌注期间 ,血浆和脑组织 NO水平明显下降 ,血浆为 (43.80± 10 .4 0 )μmol/ L、(43.6 0± 8.96 )μm ol/ L、(37.5 0± 13.6 0 )μmol/ L、(39.80± 8.2 2 )μmol/ L、(40 .70± 7.86 )μmol/ L (P<0 .0 5和 P<0 .0 1) ,脑组织为 (319.0 0± 70 .70 )μmol/ g(P>0 .0 5 ) ;ET水平显著升高 ,血浆为 (73.80± 34.70 ) ng/ L、(81.30± 32 .5 0 ) ng/ L、(78.2 0± 36 .80 ) ng/ L、(10 4 .0 0± 4 2 .0 0 ) ng/ L、(111.0 0± 5 0 .70 ) ng/ L(P<0 .0 5和 P<0 .0 1) ,脑组织为 (93.10± 4 2 .30 ) ng/ g(P<0 .0 5 ) ;使用 XNJI后 ,上述各指标的异常变化明显减轻 ,与对照组相比有显著性差异 (P<0 .0 5和 P<0 .0 1)。结论 :XNJI可提高机体 NO水平、降低 ET水平而抗 CIRI     

Suppression of Leukocyte-Enhanced Cold Ischemia/Reperfusion Injury of Liver Endothelium with the Benzoquinone Antioxidant Idebenone

Objective: Despite the large body of evidence for a major role of neutrophils and oxidant stress, the exact pathogenesis of the early ischemia/reperfusion injury after cold preservation of the liver is not well understood. The potential benefit of an antioxidant on metabolic liver function during reperfusion has been demonstrated in several studies.

Materials and Methods: We describe a cold storage/reperfusion damage model with isolated perfused pig livers, where the effects of neutrophils and idebenone, a recently developed benzoquinone antioxidant were studied. The integrity of sinusoidal endothelial cells (SEC) was estimated by hyaluronic acid concentration in perfusate and the expression of endothelial constitutive nitric oxide synthase (ecNOS) after reperfusion and compared to lipid peroxidation and antioxidant content.

Results: Hyaluronic acid displayed the highest levels and ecNOS mRNA was most depressed in livers reperfused with neutrophils after 20 h cold storage; this was accompanied by an increase in lipid peroxidation (TBARS) and a breakdown of endogenous lipophilic antioxidants (-tocopherol and coenzyme Q-10). These effects were attenuated, when neutrophils were excluded from reperfusion and almost completely abolished by the addition of 200 μmol/L idebenone.

Conclusions: These data suggest that a leukocyte-mediated damage based on reactive oxygen species markedly contributes to the reperfusion injury of SEC after cold preservation of the liver. Therefore, the presence of effective antioxidants in the early reperfusion phase may be beneficial for liver graft integrity.