Protective Effects of the Preconditioning with Different Doses of Sodium Aescinate on Tourniquet-induced Ischemic Reperfusion

Objective：To evaluate the protective effects of sodium aescinate（SA）preconditioning on the tourniquet-induced ischemia-reperfusion（l/R）injury after limbs operation.Methods：Seventy-five patients with gradeⅠ-Ⅱissued by American Society of Anesthesiology undergoing lower limb operation were randomly assigned to 3 groups：the control group,low-dose SA-treated group and high-dose SA-treated group;each group enrolled 25 patients.The patients were treated with 5 mg and 10 mg SA 30 min before tourniquet inflation in the two treatment groups separately,while the patients in the control group received normal saline.Venous blood samples were obtained before tourniquet was inflated（T0 baseline）.And 5（T1）,10（T2）,20（T3）min after tourniquet was released.The nitric oxide（NO）,malondialdehyde（MDA）and superoxide dismutase（SOD）levels were determined by commercial kits.Meanwhile,arterial pressure（MAP）and heart rate（HR）were monitored from an automatic invigilator.Results：In the control group,MDA and NO levels were increased,and SOD and MAP were decreased significantly after tourniquet deflation compared to TO baseline（P0.05）.After tourniquet deflation,MDA and NO levels in the two treated groups were significantly decreased;meanwhile,SOD levels and MAP were increased,and the variations of HR were more stable compared with the control group（all P0.05）.There was no significant difference in all of the above between the two treated groups（P0.05）. Conclusion：The protective effects of SA preconditioning on tourniquet-induced limb l/R injury might possibly contribute to the increasing of SOD levels,and MAP and the decreasing of MDA and NO levels.

Effects of Compound Shenhua Tablet(复方肾华片) on Renal Tubular Na^+-K^+-ATPase in Rats with Acute Ischemic Reperfusion Injury

Objective： To observe the effect of Compound Shenhua Tablet （复方肾华片, SHT） on the sodium- potassium-exchanging adenosinetriphosphatase （Na＋-K＋-ATPase） in the renal tubular epithelial cells of rats with acute ischemic reperfusion and to investigate the mechanisms underlying the effects of SHT on renal ischemic reperfusion injury （RIRI）. Methods： Fifty male Wistar rats were randomly divided into the sham surgery group, model group, astragaloside group [150 mg/（kg.d）], SHT low-dose group [1.5 g/（kg,d）] and SHT high-dose group [3.0 g/（kg.d）], with 10 rats in each group. After 1 week of continuous intragastric drug administration, surgery was performed to establish the model. At either 24 or 72 h after the surgery, 5 rats in each group were sacrificed, blood biochemistry, renal pathology, immunoblot and immunohistochemical examinations were performed, and double immunofluorescence staining was observed under a laser confocal microscope. Results： Compared with the sham surgery group, the serum creatinine （SCr） and blood urea nitrogen （BUN） levels were significantly increased, Na＋-K＋-ATPase protein level was decreased, and kidney injury molecule-1 （KIM-1） protein level was increased in the model group after the surgery （P〈0.01 or P〈0.05）. Compared with the model group, the SCr, BUN, pathological scores, Na＋-K＋-ATPase, and the KIM-1 protein level of the three treatment groups were significantly improved at 72 h after the surgery （P〈0.05 or P〈0.01）. And the SCr, BUN of the SHT low- and high-dose groups, and the pathological scores of the SHT high-dose group were significantly lower than those of the astragaloside group （P〈0.05）. The Iocalizations of Na＋-K＋-ATPase and megalin of the model group were disrupted, with the distribution areas overlapping with each other and alternately arranged. The severity of the disruption was slightly milder in three treatment groups compared with that of the model group. The results of immunofluorescence staining showed that the SHT high-dose group had a superior effect as compared with the astragaloside group and the SHT low-dose group. Conclusions： The SHT effectively alleviated RIRI caused by ischemic reperfusion, promoted the recovery of the polarity of renal tubular epithelial cells, and protected the renal tubules. The therapeutic effects of SHT were superior to those of astragaloside as a single agent.

Changes of cTnI in myocardial ischemic and reperfusion injury during correction of cardiac defects in children

Objective The purpose of this study is to investgate changes of cTnI in myocardial ischemic and reperfusion injury during correction of cardiac defects in children. Methods From June, 1999 to May,2000,45 children (30 male, 15 female) undergoing correction of cardiac defects were divided into three groups randomly: group Ⅰ no myocardial ischemia,group Ⅱ myocardial ischemia less than 60 minutes, group Ⅲmyocardial ischemia 】 60 minutes. There were no significant differences in the three groups in age, sex ratio, C/T ratio, or left ventricular function. Blood samples for analysis were collected before skin incision and at time intervals up to 6 days postoperatively. Analysis of creatine kinase MB.LDH and cardiac-specific troponin I was used for the detection of myocardial damage. Meantime, the ECG was checked for myocardial infarction. After the reperfusion, myocardial tissue was obtained from the free wall of right ventricle myocardial structure studies. Results The level of cTnI was increased

The influence of aprotinin on the mRNA expression of P-selectin and ICAM-1 in the in situ lung tissue after ischemic cold storage and reperfusion

To explore the influence of aprotinin on the mRNA expression of P-selectin and ICAM-1 in lung tissue after ischemic reperfusion.Methods Thirty New Zealand white rabbits were randomly divided into 3 groups:control group,LPD group and aprotinin group.In situ rabbit lung preservation model was established.In control group,the left lower lung lobe was stored at 10℃ in a specially made lung preservation container for 2 hours and reperfused for another 2 hours.In LPD group and aprotinin group,the left lower lobe was perfused with LPD solution or aprotinin containing LPD solution,respectively,after left lung hilus was clamped.The other procedures were the same as those in control group.The lung tissue was harvested at different time intervals including preclamping lung hilus,2 hours after clamping and 2 hours after reperfusion.The mRNA expression of ICAM-1 and P-selectin in the lung tissue was detected with RT-PCR technique.Results The contents of mRNA of P-selectin at 2 hours after reperfusion in control group and LPD group were significant higher than pre-ischemia and 2 hours after champing the left lung hilus.There was no such significant difference in aprotinin group.The mRNA expression of P-selectin in aprotinin group at 2 hours after reperfusion was significantly lower than that in control group and LPD group.The ICAM-1 mRNA expression at 2 hours after Ischemia and 2 hours after reperfusion in control group and LPD group was significantly higher than the pre-ischemia and its was significantly higher than that in aprotinin group.Conclusion Aprotinin can inhibit the upregulation of the mRNA expression of P selectin and ICAM-1 after ischemia reperfusion in the lung tissue,so the addition of aprotinin in LPD solution may reduce the ischemia reperfusion injury in lung tissue.5 refs,1 tab.

Effects of the mitochondrial calcium uniporter on cerebral edema in a rat model of cerebral ischemia reperfusion injury

The present study investigated the effects of the mitochondrial calcium uniporter inhibitor ruthenium red and the agonist spermine on cerebral edema in rats with cerebral ischemia reperfusion injury. Left middle cerebral artery occlusion （MCAO） was induced in rats using the suture method. Following 24 hours of ischemic reperfusion, neurological function scores of rats with MCAO, and rats pretreated with ruthenium red and spermine were significantly lower, however, water content of brain tissue, aquaporin 4 expression and immunoglobulin G （IgG） exudation were significantly higher than those of sham-operated rats. Compared with MCAO rats and spermine-treated rats, neurological function scores were considerably higher, and brain tissue water content, aquaporin 4 expression and IgG exudation decreased in ruthenium red-treated rats. These findings suggest that preventive application of the mitochondrial calcium uniporter inhibitor ruthenium red can significantly decrease aquaporin 4 and IgG expression, influence the permeability of the blood brain barrier, and thereby decrease the extent of cerebral edema.

miR-21-3p alleviates neuronal apoptosis during cerebral ischemiareperfusion injury by targeting SMAD2

Cerebral ischemia is due to the formation of blood clots or embolisms in the brain arteries,which leads to local brain tissue necrosis and neural cell apoptosis.Recent studies have shown that microRNA(miRNA)plays an important regulatory role in the pathological process of ischemic injury.The aim of this study is to investigate the role and the mechanism of miR-21-3p and drosophila mothers against decapentaplegic 2(SMAD2)in cerebral ischemic reperfusion injured(CIRI)neural cells.The CIRI model was established by oxygen-glucose deprivation and recovery process for N2a cells.The cell viability and the apoptotic was evaluated by MTT assay and the Flow Cytometer,respectively.The expression of miR-21-3p and SMAD2 mRNA was detected by real-time fluorescence quantitative PCR(qRT-PCR),and the expression of SMAD2 and apoptotic-related proteins were detected by Western Blotting.Our results showed that miR-21-3p is down-regulated,and SMAD2 is up-regulated in CIRI.Overexpression of miR-21-3p inhibits the apoptosis of neural cells in CIRI.miR-21-3p targets SMAD2 and inhibits SMAD2 expression.Overexpression of SMAD2 eliminates the protective effect of over-expression of miR-21-3p on neural cells in CIRI.Token together,this study provides a theoretical basis for the mechanism of ischemic reperfusion injury in neural cells and a new molecular target for ischemic stroke therapy.

Neuroprotection of total steroid saponins from Dioscorea zingiberensis C.H.Wright against transient focal cerebral ischemia-reperfusion injury in rats via its anti-inflammatory and anti-apoptotic effects

OBJECTIVE The total steroid saponins(TSSN)isolated from Dioscorea zingiberensis C.H.Wright(D.zingiberensis)has shown a variety of beneficial bioactivities.However,there are no reports about the neuroprotective effects of the TSSN until now.Therefore,we explored the neuroprotective effects of TSSN on rats against transient focal cerebral ischemia-reperfusion(I/R)and the underlying mechanisms.METHODS The healthy adult Sprague-Dawley rats were randomly assigned into six groups.After pre-treatment with the TSSN intragastrically for six days,the rats were subjected to the ischemia injury by the surgery of middle cerebral artery occlusion(MCAO)for 90 min.Some indexes were evaluated and detected.RESULTS As compared to the I/R group,TSSN group of rats,especially given the 30 mg·kg^-1 of TSSN,not only marked reduction in the neurological deficit scores,cerebral infarct volume,and brain edema,but also an increase in neuron survival(Nissl bodies)in the hippocampal cornuammons 1(CA1)and cortex hemisphere of the ipsilateral ischemia.At the same time,the inflammatory cytokines in serum induced by MCAO were significantly alleviated by the TSSN pre-administration.What′s more,the increase of caspase-3 was evidently reduced in the CA1 and cortex of the hemisphere injured brain.Finally,the down-regulating anti-apoptotic Bcl-2 and up-regulating pro-apoptotic Bax proteins were obviously suppressed.CONCLUSION TSSN plays a potential neuroprotective role against a severe injury induced by transient focal cerebral ischemic reperfusion in a rat experimental model,and this role may be mediated by its antiinflammatory and anti-apoptotic actions.

MRI Investigation of New Approach to Improve the Recovery of Myocardial Ischemia Reperfusion Injury by Treatment with Intralipid®

Background: Despite advances in revascularization and thrombolytic therapy, the outcome of patients after acute myocardial infarction (MI) could be complicated by ischemia reperfusion injury (IRI) and subsequent ventricular remodeling. Inflammation plays a central role in IRI. Intralipid® has been shown to reduce infarct size after IRI, but its effects on myocardial inflammation have not been addressed. The goal of this study is to investigate the effects of Intralipid® on in-situ myocardial inflammation and to better characterize its cardio-protective effects. Methods and Results: Cellular MRI was used to evaluate myocardial inflammation of iron-oxide-labeled macrophage infiltration. Cardiac MRI was used to evaluate global and regional ventricular wall motion, as well as myocardial perfusion and infarction in a rat model. Our results show that the Intralipid® treatment following IRI can preserve global and regional ventricular wall motion, and reduce the infarct size. The In-tralipid®-treated rats exhibit reduced myocardial macrophage infiltration, indicating reduced in-situ myocardial inflammation. Conclusions: Our results indicate that the Intralipid® treatment can protect the heart against IRI and can specifically reduce in-situ myocardial inflammation. Additional study is needed to assess if treatment using Intralipid® after LAD occlusion could improve the recovery of patients suffering from a heart attack and also reduce future development of heart failure.

Buyanghuanwu decoction promotes angiogenesis after cerebral ischemia/reperfusion injury：mechanisms of brain tissue repair

Buyanghuanwu decoction has been shown to protect against cerebral ischemia/reperfusion injury,but the underlying mechanisms remain unclear.In this study,rats were intragastrically given Buyanghuanwu decoction,15 m L/kg,for 3 days.A rat model of cerebral ischemia/reperfusion injury was established by middle cerebral artery occlusion.In rats administered Buyanghuanwu decoction,infarct volume was reduced,serum vascular endothelial growth factor and integrin αvβ3 levels were increased,and brain tissue vascular endothelial growth factor and CD34 expression levels were increased compared with untreated animals.These effects of Buyanghuanwu decoction were partially suppressed by an angiogenesis inhibitor（administered through the lateral ventricle for 7 consecutive days）.These data suggest that Buyanghuanwu decoction promotes angiogenesis,improves cerebral circulation,and enhances brain tissue repair after cerebral ischemia/reperfusion injury.

Inhibition of cerebral ischemia/reperfusion injuryinduced apoptosis:nicotiflorin and JAK2/STAT3 pathway

Nicotiflorin is a flavonoid extracted from Carthamus tinctorius.Previous studies have shown its cerebral protective effect,but the mechanism is undefined.In this study,we aimed to determine whether nicotiflorin protects against cerebral ischemia/reperfusion injury-induced apoptosis through the JAK2/STAT3 pathway.The cerebral ischemia/reperfusion injury model was established by middle cerebral artery occlusion/reperfusion.Nicotiflorin（10 mg/kg） was administered by tail vein injection.Cell apoptosis in the ischemic cerebral cortex was examined by hematoxylin-eosin staining and terminal deoxynucleotidyl transferase d UTP nick end labeling assay.Bcl-2 and Bax expression levels in ischemic cerebral cortex were examined by immunohistochemial staining.Additionally,p-JAK2,p-STAT3,Bcl-2,Bax,and caspase-3 levels in ischemic cerebral cortex were examined by western blot assay.Nicotiflorin altered the shape and structure of injured neurons,decreased the number of apoptotic cells,down-regulates expression of p-JAK2,p-STAT3,caspase-3,and Bax,decreased Bax immunoredactivity,and increased Bcl-2 protein expression and immunoreactivity.These results suggest that nicotiflorin protects against cerebral ischemia/reperfusion injury-induced apoptosis via the JAK2/STAT3 pathway.

The role of glycogen synthase kinase 3 beta in brain injury induced by myocardial ischemia/reperfusion injury in a rat model of diabetes mellitus

Myocardial ischemia/reperfusion injury can lead to severe brain injury.Glycogen synthase kinase 3 beta is known to be involved in myocardial ischemia/reperfusion injury and diabetes mellitus.However,the precise role of glycogen synthase kinase 3 beta in myocardial ischemia/reperfusion injury-induced brain injury is unclear.In this study,we observed the effects of glycogen synthase kinase 3 beta on brain injury induced by myocardial ischemia/reperfusion injury in diabetic rats.Rat models of diabetes mellitus were generated via intraperitoneal injection of streptozotocin.Models of myocardial ischemia/reperfusion injury were generated by occluding the anterior descending branch of the left coronary artery.Post-conditioning comprised three cycles of ischemia/reperfusion.Immunohistochemical staining and western blot assays demonstrated that after 48 hours of reperfusion,the structure of the brain was seriously damaged in the experimental rats compared with normal controls.Expression of Bax,interleukin-6,interleukin-8,terminal deoxynucleotidyl transferase d UTP nick end labeling,and cleaved caspase-3 in the brain was significantly increased,while expression of Bcl-2,interleukin-10,and phospho-glycogen synthase kinase 3 beta was decreased.Diabetes mellitus can aggravate inflammatory reactions and apoptosis.Ischemic post-conditioning with glycogen synthase kinase 3 beta inhibitor lithium chloride can effectively reverse these changes.Our results showed that myocardial ischemic post-conditioning attenuated myocardial ischemia/reperfusion injury-induced brain injury by activating glycogen synthase kinase 3 beta.According to these results,glycogen synthase kinase 3 beta appears to be an important factor in brain injury induced by myocardial ischemia/reperfusion injury.

By regulating IP3/PKC/TRPV4 pathway hyperoside induces endothelium-dependent vasodilatation in rat basilar artery following four vessel occlusion ischemia reperfusion

OBJECTIVE To investigate regulatory effects of hyperoside(Hyp)on IP3/PKC/TRPV4 pathway in rat cerebral basilar artery(CBA)subjected to global cerebral ischemia-reperfusion(I/R).METHODS The model of global cerebral I/R in rats was established by four-vessel occlusions methods.The treated rats were administrated with Hyp(50 mg·kg^-1)group,Hyp(50 mg·kg^-1)+HC-067047(10 mg·kg^-1),Hyp(50 mg·kg^-1)+2APB(2 mg·kg^-1),Hyp(50 mg·kg^-1)+BisI(2.5 mg·kg^-1),Hyp(50 mg·kg^-1)+2APB(2 mg·kg^-1)+BisI(2.5 mg·kg^-1).Hematoxylin-eosin(HE)and Nissl staining were performed and the contents of methane dicarboxylic aldehyde(MDA),neuron-specific enolase(NSE),S100β and the activity of lactic dehydrogenase(LDH)in serum were measured by enzyme-linked immunosorbnent assay(ELISA).The specific blocker N-nitro-L-arginine-methyl-ester(L-NAME)and indomethacin(Indo)were used to delete the prostacyclin(PGI2)and nitric oxide(NO)dependent relaxation.The protein expression level of TRPV4 was detected by Western blotting.Ca2+intensity in vascular smooth muscle cells was measured by confocal laser scanning microscope and flow cytometry was performed to observe the apoptosis of CBA endothelial cells after in vivo administration.RESULTS Hyp induced a dose-dependent relaxation of CBA in IR rats via a PGI2 and NO independent manner,as evidenced by alleviated patho⁃logical changes and up-regulated expression of TRPV4 protein in the endothelial cells from cerebral vessels.Hyp signifi⁃cantly reduced the contents of MDA,NSE,S100βand the activity of LDH in serum and decreased the fluorescence intensity of Ca2+in cerebral vascular smooth muscle cells by in vivo administration.The apoptotic rate of endothelial cells in Hyp treated group was significantly less than that in IR group.CONCLUSION Hyp does in fact ameliorate I/R injury by regulatingIP3/PKC/TRPV4 pathway.

Monocarboxylate transporter 4 plays a significant role in the neuroprotective mechanism of ischemic preconditioning in transient cerebral ischemia

Monocarboxylate transporters（MCTs）, which carry monocarboxylates such as lactate across biological membranes, have been associated with cerebral ischemia/reperfusion process. In this study, we studied the effect of ischemic preconditioning（IPC） on MCT4 immunoreactivity after 5 minutes of transient cerebral ischemia in the gerbil. Animals were randomly designated to four groups（sham-operated group, ischemia only group, IPC ＋ sham-operated group and IPC ＋ ischemia group）. A serious loss of neuron was found in the stratum pyramidale of the hippocampal CA1 region（CA1）, not CA2/3, of the ischemia-only group at 5 days post-ischemia; however, in the IPC ＋ ischemia groups, neurons in the stratum pyramidale of the CA1 were well protected. Weak MCT4 immunoreactivity was found in the stratum pyramidale of the CA1 in the sham-operated group. MCT4 immunoreactivity in the stratum pyramidale began to decrease at 2 days post-ischemia and was hardly detected at 5 days post-ischemia; at this time point, MCT4 immunoreactivity was newly expressed in astrocytes. In the IPC ＋ sham-operated group, MCT4 immunoreactivity in the stratum pyramidale of the CA1 was increased compared with the sham-operated group, and, in the IPC ＋ ischemia group, MCT4 immunoreactivity was also increased in the stratum pyramidale compared with the ischemia only group. Briefly, present findings show that IPC apparently protected CA1 pyramidal neurons and increased or maintained MCT4 expression in the stratum pyramidale of the CA1 after transient cerebral ischemia. Our findings suggest that MCT4 appears to play a significant role in the neuroprotective mechanism of IPC in the gerbil with transient cerebral ischemia.

Synergistic Protection of Danhong Injection (丹红注射液) and Ischemic Postconditioning on Myocardial Reperfusion Injury in Minipigs

Objective： To explore the synergistic protection of Danhong Injection （丹红注射液,DHI） and ischemic postconditioning on myocardial reperfusion injury in minipigs.Methods： Acute myocardial infarction model was made by balloon occlusion in left anterior descending coronary artery （LAD） of minipigs,and then postconditioning was simulated through inflation/deflation of the angioplasty balloon.Minipigs were divided into four groups： the sham operation group （SH group）,the ischemia/reperfusion group （I/R group）,the ischemic postconditioning group （POC group） and DHI combined with ischemic postconditioning group （PAD group,DHI 20 mL through ear vein）,six in each group.After 24-h continuous observation,myocardial infarction size was assessed by triphenyltetrazolium staining （TTC）.Morphological changes of ischemic myocardium were observed by light microscopy,and cardiomyocyte ultrastructure was studied with electron microscopy.The superoxide dismutase （SOD） and malondialdehyde （MDA） activity in heart homogenates were measured by a biochemical method.Results： The myocardial infarction size was smaller in the POC group than in the I/R group （0.26±0.02 vs.0.37±0.09,P〈0.05）,and the PAD group （0.14±0.08） displayed a significantly reduced infarction size relative to the I/R group （P〈0.01） and POC group （P〈0.05）.The damage of myocardial tissue was severe in the I/R group shown by light and electron microscopy： myocardial fibers disorder,sarcoplasmic dissolution,myofilament fracture,mitochondria swelling and even vacuolization formation and a large number of inflammatory cell infiltrations.Compared with the I/R group,reduction of reperfusion injury in the PAD group included more orderly arranged myocardial fibers,less infiltration of inflammatory cells and maintenance of mitochondrial integrity.Compared with the I/R group,the damage of myocardial tissue in the POC group was improved,but not as significant as that in the PAD group.SOD levels in the POC group and the PAD group were significantly higher than those in the I/R group （96.96±13.43,112.25±22.75 vs.76.32±10.63,P〈0.05）,and MDA was significantly lower in the POC group and the PAD group compared to the I/R group （1.27±0.19,1.09±0.21 vs.1.47±0.16,P〈0.05）.Conclusion： DHI and ischemic postconditioning show a synergistic cardioprotection on myocardial reperfusion injury in minipigs.

Protective Mechanism of Cordyceps sinensis Treatment on Acute Kidney Injury-Induced Acute Lung Injury through AMPK/mTOR Signaling Pathway

Objective: To investigate protective effect of Cordyceps sinensis(CS) through autophagyassociated adenosine monophosphate-activated protein kinase(AMPK)/mammalian target of rapamycin(mTOR) signaling pathway in acute kidney injury(AKI)-induced acute lung injury(ALI). Methods: Forty-eight male Sprague-Dawley rats were divided into 4 groups according to a random number table, including the normal saline(NS)-treated sham group(sham group), NS-treated ischemia reperfusion injury(IRI) group(IRI group), and low-(5 g/kg·d) and high-dose(10 g/kg·d) CS-treated IRI groups(CS1 and CS2 groups), 12 rats in each group. Nephrectomy of the right kidney was performed on the IRI rat model that was subjected to 60 min of left renal pedicle occlusion followed by 12, 24, 48, and 72 h of reperfusion. The wet-to-dry(W/D) ratio of lung, levels of serum creatinine(Scr), blood urea nitrogen(BUN), inflammatory cytokines such as interleukin-βand tumor necrosis factor-α, and biomarkers of oxidative stress such as superoxide dismutase, malonaldehyde(MDA) and myeloperoxidase(MPO), were assayed. Histological examinations were conducted to determine damage of tissues in the kidney and lung. The protein expressions of light chain 3 Ⅱ/light chain 3 Ⅰ(LC3-Ⅱ/LC3-Ⅰ), uncoordinated-51-like kinase 1(ULK1), P62, AMPK and mTOR were measured by Western blot and immunohistochemistry, respectively. Results: The renal IRI induced pulmonary injury following AKI,resulting in significant increases in W/D ratio of lung, and the levels of Scr, BUN, inflammatory cytokines, MDA and MPO(P<0.01);all of these were reduced in the CS groups(P<0.05 or P<0.01). Compared with the IRI groups, the expression levels of P62 and mTOR were significantly lower(P<0.05 or P<0.01), while those of LC3-Ⅱ/LC3-Ⅰ, ULK1, and AMPK were significantly higher in the CS2 group(P<0.05 or P<0.01). Conclusion:CS had a potential in treating lung injury following renal IRI through activation of the autophagy-related AMPK/mTOR signaling pathway in AKI-induced ALI.

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℃-38℃） ischemic group and a mild hypothermic （31℃-32℃） 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.

Remote ischemia conditioning-an endogenous cardioprotective strategy from outside the heart

Objective A general review was made of studies involving： （1） The experimental evidence of remote ischemic preconditioning （RIPC） and relative clinical studies, （2） The experimental and clinical evidences of remote ischemic postconditioning （RIPOC）, （3） The potential mechanistic pathways underlying their protective effects.Data sources The data used in this review were mainly from manuscripts listed in PubMed that were published in English from 1986 to 2010. The search terms were ＂myocardial ischemia reperfusion injury＂, ＂ischemia preconditioning＂,＂ischemia postconditioning＂, ＂remote preconditioning＂ and ＂remote postconditioning＂.Study selection （1） Clinical and experimental evidence that both RIPC and RIPOC produce preservation of ischemia reperfusion injury （IRI） of myocardium and other organs, （2） Studies related to the potential mechanisms, by which remote ischemic conditioning protects myocardium against IRI.Results Both RIPC and RIOPC have been shown to attenuate myocardial IRI in laboratory animals. Also, their cardioprotective effects have appeared in some clinical studies. Except the external, the detailed internal mechanisms of remote ischemic conditioning have been generally described. Through these descriptions better protocols can be developed to provide improved cardioprotective procedures.Conclusions Remote ischemic conditioning is an endogenous cardioprotective mechanism from outside the heart that protects against myocardial IRI and represents a general form of inter-organ protection. Remote ischemic conditioning may have an immense impact on clinical practice in the near future.