Ischemia Injury In Rats Research Articles

Picroside II Diminishes Oxidative Stress Induced By Cerebral Ischemic Injury In Rats

Stoke is a major health problem and there is no effective treatment of the disease. Therefore, finding novel chemicals that can be used to treat stroke has been an intensive research area. Picroside II seems to be a promising compound, yet its utilization in particular, the dosage and time window of its application after stroke has not been optimized. In this study, we wanted to address this problem using Malondialdehyde (MDA) and superoxide dismutase (SOD) as two parameters. MDA, a lipid peroxidation product formed by reactions between free radicals and polyunsaturated fatty acids, can be measured to reflect the magnitude of oxidative stress [1]. The aldehyde of MDA can occur crosslinking reaction with the amino groups of phosphatidylserine in neuronal membrane phospholipids [2]. The lipid peroxidation of biomembrane and its lipid peroxide products can also implicate the protein in the membrane to result in oxidative damage and apoptosis[3,4]. The content of MDA can reflect the levels of the free radicals and lipid peroxidation in tissue [5,6]. When the level of oxygen free radicals (OFR) elevates, SOD can react with superoxide anion with the generation of hydrogen peroxide. And hydrogen peroxide (H2O2) can turn into water under the effect of catalase and glutathione peroxidase to remove the OFR to protect cells from damage. Therefore, the level of SOD activity can reflect the ability of the body in clearing OFR [7,8]. Cell culture experiments confirmed that picroside II can reduce H2O2-induced injury in PC12 cells and improve cell survival [9,10,11]. Animal experiments showed that picroside II, an active ingredient of traditional Chinese medicine, can also inhibit the expression of inflammatory factors and apoptosis in cerebral ischemic penumbra, thus improve the neurobehavioral functions in rats [12,13,14]. Our group dealt the rats with different doses of picroside II at different ischemic time, and the result showed that the optimized therapeutic dose and time window of picroside II in cerebral ischemia reperfusion injury was ischemia 1.5 h with 20mg/kg body weight by intraperitoneal injection [15]. This study was designed to detect the MDA levels and SOD activity in blood and brain tissue to further explore the anti-oxidation effect and the optimal therapeutic dose and time window of picroside II in cerebral ischemic injury. Abstract

Protective effect of Panax quinquefolium 20(S)-protopanaxadiol saponins, isolated from Pana quinquefolium, on permanent focal cerebral ischemic injury in rats

Oxidative stress is significant in the pathogenesis of cerebral ischemia. Panax quinquefolium 20(S)-protopanaxadiol saponins (PQDS) have been demonstrated to exhibit a variety of biological effects in the cardiovascular system as a result of their antioxidant properties. However, little is known regarding the effect of PQDS on cerebral ischemia. The purpose of this study was to investigate whether PQDS exhibited protective effects against cerebral ischemia. A model of cerebral ischemia was induced by middle cerebral artery occlusion (MCAO) in Sprague-Dawley rats. Adult male rats were randomly divided into five groups: Sham, MCAO and PQDS treatment groups at doses of 12.5, 25.0 and 50.0 mg/kg. The effects of PQDS on neurological deficits, cerebral infarct area, brain water content, and the malondialdehyde (MDA) and Ca2+ levels and Na+-K+-ATPase and superoxide dismutase (SOD) activities in the brain tissue were analyzed, and the nitric oxide (NO) content and nitric oxide synthase (NOS) activity in the serum were evaluated. Moreover, the expression of Bcl-2 was analyzed using western blotting. Pretreatment with PQDS (25.0 and 50.0 mg/kg) significantly reduced the neurological deficit score, decreased the infarcted area and decreased the brain water content from 83.09 to 80.27% (P<0.05). In addition, PQDS pretreatment decreased the NOS activity and the NO levels in the serum compared with those in the MCAO group. Furthermore, pretreatment with PQDS (25.0 and 50.0 mg/kg) significantly increased the activities of SOD and Na+-K+-ATPase and decreased the levels of Ca2+ and MDA in the brain tissue (P<0.05) compared with those in the MCAO group. Pretreatment with PQDS (25.0 and 50.0 mg/kg) also increased the protein expression level of Bcl-2 compared with that in the MCAO group. The histopathological results demonstrated the protective effect of PQDS on ischemic injury. The results indicated that PQDS has protective effects against ischemic injury in rats. The mechanism may be associated with the inhibition of oxidative stress and apoptosis.

Effects of hydrogen sulfide on inflammatory factors in acute myocardial ischemia injury in rats

Effects of hydrogen sulfide on inflammatory factors in acute myocardial ischemia injury in rats

Short-term treadmill exercise preserves sensory-motor function through inhibiting apoptosis in the hippocampus of hypoxic ischemia injury rat pups

Perinatal hypoxic ischemia injury is a common cause of morbidity and mortality in neonates. Physical exercise may ameliorate neurological impairment by impeding neuronal loss following various brain insults. In the present study, the effect of treadmill exercise on sensory-motor function in relation with hippocampal apoptosis following hypoxic ischemia brain injury was investigated. Sensory-motor function was determined by walking initiation test and apoptosis was detected by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) staining and caspase-3 immunohistochemistry. On postnatal 7 day, left common carotid artery of the neonatal rats was ligated for two hours and then the neonatal rats were exposed to hypoxia conditions for one hour. The rat pups in the exercise groups were forced to run on a motorized treadmill for 30 min once a day for 10 days, starting 22 days after induction of hypoxic ischemia brain injury. Hypoxic ischemia caused sensory-motor disturbance with enhancement of apoptosis in the hippocampus. Short-term treadmill exercise suppressed hypoxic ischemia injury-induced apoptosis in the hippocampus, and preserved sensory-motor function of hypoxic ischemia injury rat pups.

Inhibition of HDAC2 Protects the Retina From Ischemic Injury

Protein acetylation is an essential mechanism in regulating transcriptional and inflammatory events. Studies have shown that nonselective histone deacetylase (HDAC) inhibitors can protect the retina from ischemic injury in rats. However, the role of specific HDAC isoforms in retinal degenerative processes remains obscure. The purpose of this study was to investigate the role of HDAC2 isoform in a mouse model of ischemic retinal injury. Localization of HDAC2 in mice retinas was evaluated by immunohistochemical analyses. To investigate whether selective reduction in HDAC2 activity can protect the retina from ischemic injury, Hdac2⁺/⁻ mice were utilized. Electroretinographic (ERG) and morphometric analyses were used to assess retinal function and morphology. Our results demonstrated that HDAC2 is primarily localized in nuclei in inner nuclear and retinal ganglion cell layers, and HDAC2 activity accounted for approximately 35% of the total activities of HDAC1, 2, 3, and 6 in the retina. In wild-type mice, ERG a- and b-waves from ischemic eyes were significantly reduced when compared to pre-ischemia baseline values. Morphometric examination of these eyes revealed significant degeneration of inner retinal layers. In Hdac2⁺/⁻ mice, ERG a- and b-waves from ischemic eyes were significantly greater than those measured in ischemic eyes from wild-type mice. Morphologic measurements demonstrated that Hdac2⁺/⁻ mice exhibit significantly less retinal degeneration than wild-type mice. This study demonstrated that suppressing HDAC2 expression can effectively reduce ischemic retinal injury. Our results support the idea that the development of selective HDAC2 inhibitors may provide an efficacious treatment for ischemic retinal injury.

Ferulic Acid Attenuates the Injury-Induced Decrease of Protein Phosphatase 2A Subunit B in Ischemic Brain Injury

BackgroundFerulic acid provides a neuroprotective effect during cerebral ischemia through its anti-oxidant function. Protein phosphatase 2A (PP2A) is a serine and threonine phosphatase that contributes broadly to normal brain function. This study investigated whether ferulic acid regulates PP2A subunit B in a middle cerebral artery occlusion (MCAO) animal model and glutamate toxicity-induced neuronal cell death.Methodology/Principal FindingsMCAO was surgically induced to yield permanent cerebral ischemic injury in rats. The rats were treated with either vehicle or ferulic acid (100 mg/kg, i.v.) immediately after MCAO, and cerebral cortex tissues were collected 24 h after MCAO. A proteomics approach, RT-PCR, and Western blot analyses performed to identification of PP2A subunit B expression levels. Ferulic acid significantly reduced the MCAO-induced infarct volume of the cerebral cortex. A proteomics approach elucidated the reduction of PP2A subunit B in MCAO-induced animals, and ferulic acid treatment prevented the injury-induced reduction in PP2A subunit B levels. RT-PCR and Western blot analyses also showed that ferulic acid treatment attenuates the injury-induced decrease in PP2A subunit B levels. Moreover, the number of PP2A subunit B-positive cells was reduced in MCAO-induced animals, and ferulic acid prevented these decreases. In cultured neuronal cells, ferulic acid treatment protected cells against glutamate toxicity and prevented the glutamate-induced decrease in PP2A subunit B.Conclusions/SignificanceThese results suggest that the maintenance of PP2A subunit B by ferulic acid in ischemic brain injury plays an important role for the neuroprotective function of ferulic acid.

To Optimize the Therapeutic Dose and Time Window of Picroside II in Cerebral Ischemic Injury in Rats by Orthogonal Test

The paper aims to optimize the therapeutic dose and time window of picroside II by orthogonal test in cerebral ischemic injury in rats. The forebrain ischemia models were established by bilateral common carotid artery occlusion (BCCAO) methods. The successful models were randomly divided into sixteen groups according to orthogonal experimental design and treated by injecting picroside II intraperitonenally at different ischemic time with different dose. The concentrations of neuron-specific enolase (NSE), neuroglial marker protein S100B and myelin basic protein (MBP) in serum were determined by enzyme linked immunosorbent assay to evaluate the therapeutic effect of picroside II in cerebral ischemic injury. The results indicated that best therapeutic time window and dose of picroside II in cerebral ischemic injury were ischemia 1.5 h with 20 mg/kg body weight according to the concentrations of NSE, S100B and MBP in serum. It is concluded that according to the principle of lowest therapeutic dose with longest time window, the optimized therapeutic dose and time window are injecting picroside II intraperitonenally with 20 mg/kg body weight at ischemia 1.5 h in cerebral ischemic injury in rats.

The Neuroprotective Effect of Picroside II and Its Best Therapeutic Dose and Time Window in Cerebral Ischemic Injury in Rats

Objective: To study the neuroprotective effect of picrosede II and explore the best therapeutic dose and time window according to orthogonal design in cerebral ischemic injury in rats. Methods: The forebrain ischemia rat models were established by bilateral common carotid artery occlusion (BCCAO) method. The successful models were randomly grouped according to orthogonal experimental design and treated by injecting picroside II intraperitoneally at different ischemic time with different doses. The contents of neuron-specific enolase (NSE), neuroglial marker protein S100B and myelin basic protein (MBP) in serum and brain tissue were determined by enzyme linked immunosorbent assay (ELISA) to evaluate the therapeutic effect of picroside II in cerebral ischemic injury. Results: The best therapeutic time window and dose of picroside II in cerebral ischemic injury may be 1) ischemia 1.5 h with 20 mg/kg and ischemia 1.5 h with 10 mg/kg body weight according to the content of NSE in serum and brain tissue respectively, 2) ischemia 1.5 h with 20 mg/kg according to the content of S100B in both serum and brain tissue, and 3) ischemia 1.5 h with 20 mg/kg and ischemia 1.5 h with 10 mg/kg according to the content of MBP in serum and brain tissue respectively. Conclusion: Based on the principle of the minimization of therapeutic drug dose and maximization of therapeutic time window, the optimal composition of the therapeutic dose and time window of picroside II in treating cerebral ischemic injury should be achieved by injecting picroside II intraperitoneally with 10-20 mg/kg body weight at ischemia 1.5 h in cerebral ischemic injury in rats.

The effect of picroside II on the expressions of AQP4, MMP9 and COX2 in cerebral ischemic injury in rats

The aim is to study the neuroprotective effect and optimize the therapeutic dose and time window of picrosede II by orthogonal test in cerebral ischemic injury in rats. The forebrain ischemia models of rats were established by bilateral common carotid artery occlusion (BCCAO) methods. The successful models were randomly grouped according to orthogonal experimental design and treated by injecting picroside II intraperitonenally with different therapeutic dose at different ischemic time. The contents of aquaporins 4 (AQP4), matrix metalloproteinases 9 (MMP 9) and cyclooxygenase 2 (COX2) in brain tissue were determined by enzyme linked immunosorbent assay to evaluate the therapeutic effect of picroside II on cerebral ischemic injury. The results indicated that the best therapeutic time window and dose of picroside II in cerebral ischemic injury should be 1) ischemia 1.5 h with 20 mg/kg body weight according to the content of AQP4; 2) ischemia 2.0 h with 20 mg/kg according to the content of MMP9; and 3) ischemia 1.5 h with 20 mg/kg according to the content of COX2 inbrain tissue. It is concluded that the optimized therapeutic dose and time window is injecting picroside II peritonenally with 10 - 20 mg/kg body weight at ischemia 1.5 - 2.0 h in cerebral ischemic injury according to the principle of lowest therapeutic dose with longest time window.

The anti-inflammatory effect of picroside II and the optimizing of therapeutic dose and time window in cerebral ischemic injury in rats

The aim is to optimize the anti-inflammatory effect and the therapeutic dose and time window of picrosede II by orthogonal test in cerebral ischemic injury in rats. The forebrain ischemia models were established by bilateral common carotid artery occlusion (BCCAO) methods in 30 Wistar rats. The successful models were randomly divided into sixteen groups according to orthogonal experimental design and treated by injecting picroside II intraperitoneally at different ischemic time with different dose. The concentrations of aquaporins 4 (AQP4), matrix metalloproteinases9 (MMP9) and cyclooxygenase 2 (COX2) in serum and brain tissue were determined by enzyme linked immunosorbent assay to evaluate the therapeutic effect of picroside II in cerebral ischemic injury. The best therapeutic time window and dose of picroside II in cerebral ischemic injury were 1) ischemia 2.0 h with 20 mg/kg and 1.5 h with 20 mg/kg body weight according to the concentration of AQP4 in serum and brain tissue; 2) ischemia 1.5 h with 20 mg/kg and ischemia 2.0 h with 20 mg/kg according to the concentrations of MMP9 in serum and brain tissue; and 3) ischemia 1.5 h with 10 mg/kg and ischemia 1.5 h with 20 mg/kg according to the concentrations of COX2 in serum and brain tissue respectively. According to the principle of the lowest therapeutic dose with the longest time window, the optimized therapeutic dose and time window were injecting picroside II intraperitoneally with 10 - 20 mg/kg body weight at ischemia 1.5 - 2.0 h in cerebral ischemic injury.

Evaluation of the anti-myocardial ischemia effect of individual and combined extracts of Panax notoginseng and Carthamus tinctorius in rats

Ethnopharmacological relevanceThe decoction of combined Panax notoginseng (Burk) F.H. Chen and Carthamus tinctorius L. has a history of use in traditional medicine for the prevention and treatment of cardiovascular diseases such as angina pectoris and myocardial infarction. Aim of the studyIn this study, we investigated the effects of individual herbal extracts and combined extracts on anti-myocardial ischemia injuries in vivo, and determined the proper dosage of Panax notoginseng (EPN) combined with Carthamus tinctorius (ECT) that could strengthen their cardio-protective effects. Meanwhile, their potential anti-oxidative stress and anti-inflammation effect were assessed. Material and MethodsSD rats were orally given individual EPN 50, 100mg/kg, ECT 100, 200mg/kg, and different combinations between them. Myocardial infarction was produced by occlusion of the left anterior descending coronary artery for 24h. Infarct area was determined with 2,3,5-triphenyltetrazolium chloride (TTC) staining. The biomarkers related to myocardial ischemia injury were determined. Simultaneously, hemodynamic parameters were monitored as left ventricular systolic pressure (LVSP), LV end-diastolic pressure (LVEDP) and maximal rate of increase and decrease of left ventricular pressure (dP/dtmax). The oxidative stress indicators and inflammatory factors were also evaluated. ResultsThe results showed EPN or ECT significantly reduced infarct size, improved cardiac function, decreased levels of creatine kinase (CK) and lactate dehydrogenase (LDH) (all P<0.05 vs. control ). EPN or ECT alone also restrained the oxidative stress related to myocardial ischemia injury as evidenced by decreased malondialdehyde (MDA) and elevated superoxide dismutase (SOD) activity (all P<0.05 vs. control). However, this cardio-protective effect was further strengthened by their combinations. Among all the combinations, EPN 50mg/kg plus ECT 200mg/kg showed predominant potential to reduce infarct size (22.21±1.72%, P<0.05 vs. each single, respectively), preserve cardiac function (P<0.05 vs. ECT 200mg/kg for LVEDP and −dP/dtmax) after myocardial ischemia injury in rats. This heart protection was confirmed with the lowered cardiac troponin I (cTnI) (P<0.05 vs. ECT 200mg/kg and EPN 50mg/kg, respectively). Oxidative stress and inflammation are the two key factors in the pathogenesis of myocardial ischemia injury. In the present study, EPN 50mg/kg plus ECT 200mg/kg markedly increased SOD and GSH-Px activity (475.30±23.60U/ml, P<0.05 vs. each single, respectively), while elevated MDA level was significantly depressed. Meanwhile, the inflammatory cascade was inhibited as evidenced by decreased cytokines such as tumor necrosis factor-α (TNF-α), C-reactive protein (CRP) and interleukin-1β (IL-1β). ConclusionThese results demonstrated EPN, ECT and their combinations exhibited significant cardio-protective effects. The findings suggest EPN combined with ECT may be therapeutically more useful for ameliorating anti-myocardial ischemia injuries than individual herbal extract, and EPN 50mg/kg plus ECT 200mg/kg is the appropriate combination in the present research. The cardio-protective effect of this combination was achieved partially by decreasing oxidative stress and repressing inflammatory cascade.

Pre-conditioned mesenchymal stem cells ameliorate renal ischemic injury in rats by augmented survival and engraftment

BackgroundIschemia is the major cause of acute kidney injury (AKI), associated with high mortality and morbidity. Mesenchymal stem cells (MSCs) have multilineage differentiation potential and can be a potent therapeutic option for the cure of AKI.MethodsMSCs were cultured in four groups SNAP (S-nitroso N-acetyl penicillamine), SNAP + Methylene Blue (MB), MB and a control for in vitro analysis. Cultured MSCs were pre-conditioned with either SNAP (100 μM) or MB (1 μM) or both for 6 hours. Renal ischemia was induced in four groups (as in in vitro study) of rats by clamping the left renal padicle for 45 minutes and then different pre-conditioned stem cells were transplanted.ResultsWe report that pre-conditioning of MSCs with SNAP enhances their proliferation, survival and engraftment in ischemic kidney. Rat MSCs pre-conditioned with SNAP decreased cell apoptosis and increased proliferation and cytoprotective genes’ expression in vitro. Our in vivo data showed enhanced survival and engraftment, proliferation, reduction in fibrosis, significant improvement in renal function and higher expression of pro-survival and pro-angiogenic factors in ischemic renal tissue in SNAP pre-conditioned group of animals. Cytoprotective effects of SNAP pre-conditioning were abrogated by MB, an inhibitor of nitric oxide synthase (NOS) and guanylate cyclase.ConclusionThe results of these studies demonstrate that SNAP pre-conditioning might be useful to enhance therapeutic potential of MSCs in attenuating renal ischemia reperfusion injury.

A novel approach to induction and rehabilitation of deficits in forelimb function in a rat model of ischemic stroke

Constraint-induced movement therapy (CIMT), which forces use of the impaired arm following unilateral stroke, promotes functional recovery in the clinic but animal models of CIMT have yielded mixed results. The aim of this study is to develop a refined endothelin-1 (ET-1) model of focal ischemic injury in rats that resulted in reproducible, well-defined lesions and reliable upper extremity impairments, and to determine if an appetitively motivated form of rehabilitation (voluntary forced use movement therapy; FUMT) would accelerate post-ischemic motor recovery. Male Sprague Dawley rats (3 months old) were given multiple intracerebral microinjections of ET-1 into the sensorimotor cortex and dorsolateral striatum. Sham-operated rats received the same surgical procedure up to but not including the drill holes on the skull. Functional deficits were assessed using two tests of forelimb placing, a forelimb postural reflex test, a forelimb asymmetry test, and a horizontal ladder test. In a separate experiment ET-1 stroke rats were subjected to daily rehabilitation with FUMT or with a control therapy beginning on post-surgery d 5. Performance and post-mortem analysis of lesion volume and regional BDNF expression were measured. Following microinjections of ET-1 animals exhibited significant deficits in contralateral forelimb function on a variety of tests compared with the sham group. These deficits persisted for up to 20 d with no mortality and were associated with consistent lesion volumes. FUMT therapy resulted in a modest but significantly accelerated recovery in the forelimb function as compared with the control therapy, but did not affect lesion size or BDNF expression in the ipsilesional hemisphere. We conclude that refined ET-1 microinjection protocols and forcing use of the impaired forelimb in an appetitively motivated paradigm may prove useful in developing strategies to study post-ischemic rehabilitation and neuroplasticity.

Dual effects of hydrogen sulphide on focal cerebral ischaemic injury via modulation of oxidative stress‐induced apoptosis

1. Hydrogen sulphide (H₂S), one of three signalling gasotransmitters, plays an important role in oxidative stress and apoptosis. However, the effects of H₂S on oxidative stress-induced apoptosis in focal cerebral ischaemic injury in rats have not been clarified. 2. In the present study, sodium hydrosulphide (NaHS) was used as the H₂S donor. Eighty-four Sprague-Dawley rats were randomly divided into six groups: sham, sham + low-dose (2.8 mg/kg) NaHS, sham + high-dose (11.2 mg/kg) NaHS, infarct, infarct + low-dose NaHS and infarct + high-dose NaHS. The focal cerebral ischaemic model was created by cranially inserting a nylon thread with a rounded tip into an internal carotid artery. Rats were killed 21 h after administration of NaHS. 3. In the infarct + low-dose NaHS compared with infarct group, infarct volume was significantly decreased and injury to the mitochondria in nerve cells was mitigated. Furthermore, significant increases were seen in mitochondrial superoxide dismutase and glutathione peroxidase activity and neuronal bcl-2 protein levels, whereas mitochondrial malondialdehyde content and neuronal bax and caspase 3 protein levels were significantly decreased, in the infarct + low-dose NaHS compared with infarct group. The effects seen in the infarct group were significantly aggravated in the infarct + high-dose NaHS group. 4. The findings of the present study provide novel evidence for the dual effects of H₂S on focal cerebral ischaemic injury via modulation of oxidative stress-induced apoptosis.

Limb Ischemia Protects Against Contrast-Induced Nephropathy

Contrast-induced acute kidney injury (CI-AKI), or nephropathy (CIN), is frequently diagnosed in the setting of coronary angiography. The incidence varies in the literature partly related to the differences in diagnostic criteria used for CIN. In a recently published article in Circulation , Maioli et al1 used a definition of an increase of ≥0.5 mg/dL over baseline serum creatinine within 3 days of the administration of contrast medium and found an incidence of 12.1% among 1490 patients who had a baseline estimated creatinine clearance of 4-fold in patients who had mild AKI (≥0.3 mg/L or …

Noninvasive limb remote ischemic preconditioning contributes neuroprotective effects via activation of adenosine A1 receptor and redox status after transient focal cerebral ischemia in rats

Purposes: To investigate whether activation of adenosine A1 receptor (A1R) through limb remote ischemic preconditioning (RIPC) by a noninvasive tourniquet contribute neuroprotective effects against rat focal cerebral ischemic injury induced by transient middle cerebral artery occlusion (MCAO). Methods: One hundred twenty-eight Sprague–Dawley (SD) rats were randomly assigned into eight groups (n=16 each): MCAO, Control, 8-cyclopentyl-1,3-dipropulxanthine (DPCPX, Adenosine A1 receptor antagonist), RIPC, DPCPX+RIPC, Vehicle+RIPC, 2-chloro-N6-cyclopentyladenosine (CCPA, Adenosine A1 receptor agonist) and CCPA+DPCPX groups. All animals underwent right middle cerebral artery occlusion (MCAO) for 2h. Limb RIPC consisted of three cycles of 5-minute ischemia followed by 5-minute reperfusion in right hind-limb by tourniquet application. Neurological deficit scores were evaluated 24h after reperfusion, and then the infarct volume was assessed with diffusion weighted imaging (DWI) and 2, 3, 5-triphenyltetrazolium chloride (TTC) staining. Inflammation was assessed by serum tumor necrosis factor α (TNFα) and NO; oxidative stress was estimated by malondialdehyde (MDA) and 4-hydroxyalkenals (4-HAD), superoxide dismutase (SOD) activity and GSH. Results: Animals in the RIPC, Vehicle+RIPC and CCPA groups developed lower neurological deficit scores and smaller brain infarct volumes than the Control group (P<0.01). Animals in the DPCPX, DPCPX+RIPC and CCPA+DPCPX groups developed higher neurological deficit scores and larger brain infarct volumes than the RIPC, Vehicle+RIPC and CCPA groups (P<0.01). DPCPX abolished the protective effects of RIPC and CCPA. RIPC or CCPA induced a significant increase in brain MnSOD (manganese SOD) activity and NO generation, and this activity was abolished by DPCPX pretreatment. RIPC or CCPA induced a significant reduction (P<0.05) in the GSH and MDA+4HDA concentration and an accumulation in the GSSG concentration in both compartments (serum and tissue) as compared with the MCAO group. Conclusions: The present study demonstrates that limb RIPC induced by noninvasive tourniquet reduces cerebral ischemic injury in rats, and the effect of neuroprotection may depend on the activation of adenosine A1 receptors. CCPA pretreatment can induce delayed ischemic tolerance against cerebral ischemia/reperfusion injury. These protective effects are associated with a reduction in oxidative stress, inflammation and endogenous antioxidant preservation.

Effects of different frequencies of electro-acupuncture at Shuigou (GV 26) on recovery of motor function in rats with focal cerebral ischemic injury

ObjectiveTo investigate the effects of different frequencies of electro-acupuncture at Shuigou (GV 26) on the latent period and wave amplitude of motor evoked potentials (MEPs) in rats with focal cerebral infarction. MethodsFifty healthy male Wistar rats were randomly divided into five groups: controls, model, 2 Hz Shuigou, 50 Hz Shuigou and 100 Hz Shuigou. There were 10 rats in each group. Using a modification of a technique for middle cerebral artery occlusion, focal cerebral ischemic injury was induced in all rats except those in the control group. The rats in the control group received no treatment. After behavioral deficit had been evaluated using the Zausinger 6-point neurological function score, the rats in the Shuigou groups underwent acupuncture and continuous wave stimulation at a frequency of 2 Hz, 50 Hz or 100 Hz (intensity 1 mA) for 10 min twice daily for 3 days. The control and model groups underwent no intervention. Zausinger 6-point neurological function score and MEPs were measured 72 h after the start of treatment. ResultsThe neurological function scores of the three Shuigou groups were significantly higher than those of the model group (P<0.05). There was no significant difference between sides in the latency and amplitude of MEPs in the model group (P>0.05). The latency on the affected side in the model group was significantly longer than that in the control group (P<0.05) and the amplitude on affected side was significantly reduced (P<0.01). After 3 days of electro-acupuncture, the latency on the affected side in the 2 Hz Shuigou group was significantly shortened (P<0.05) and the amplitude was significantly increased (P<0.05) compared with the model group. ConclusionLow frequency electro-acupuncture at Shuigou (GV 26) can promote recovery of motor function after focal cerebral ischemic injury in rats.

Primary Study for the Therapeutic Dose and Time Window of Picroside II in Treating Cerebral Ischemic Injury in Rats

The aim of this study was to explore the optimal therapeutic dose and time window of picroside II for treating cerebral ischemic injury in rats according to the orthogonal test. The middle cerebral artery occlusion (MCAO) models were established by intraluminally inserting a thread into middle cerebral artery (MCA) from left external carotid artery (ECA). The successful rat models were randomly divided into 16 groups according to the orthogonal layout of [L16(45)] and treated by injecting picroside II intraperitoneally with different doses at various times. The neurological behavioral function was evaluated by Bederson’s test and the cerebral infarction volume was measured by tetrazolium chloride (TTC) staining. The expressions of neuron specific enolase (NSE) and neuroglial mark-protein S-100 were determined by immunohistochemisty assay. The results indicated that the optimal compositions of the therapeutic dose and time window of picroside II in treating cerebral ischemic injury were ischemia 1.5 h with 20 mg/kg body weight according to Bederson’s test, 1.0 h with 20 mg/kg body weight according to cerebral infarction volume, 1.5 h with 20 mg/kg body weight according to the expressions of NSE and S-100 respectively. Based on the principle of the minimization of medication dose and maximization of therapeutic time window, the optimal composition of the therapeutic dose and time window of picroside II in treating cerebral ischemic injury should be achieved by injecting picroside II intraperitoneally with 20 mg/kg body weight at ischemia 1.5 h.

Aberrant Tubuloglomerular Feedback and HIF-1α Confer Resistance to Ischemia after Subtotal Nephrectomy

Nephron loss in a diseased kidney invokes adaptations in the remaining nephrons. Whether and how these adaptations condition the response of the kidney to injury is not known. We examined the susceptibility of the kidney after subtotal (5/6th) nephrectomy (STN) to ischemic injury in rats. GFR in STN kidneys did not significantly change after ischemia reperfusion (IR), whereas GFR fell by 70% after IR in unilateral nephrectomy controls. In micropuncture experiments, single-nephron GFR responses mirrored the whole-kidney responses: in STN, single-nephron GFR decreased by 7% after IR compared with 28% in controls. Furthermore, we found that tubuloglomerular feedback, a mechanism that links proximal tubular injury to a fall in GFR, was inoperative in STN but was normal in controls. Restoration of normal feedback in STN attenuated the functional resistance to IR. In addition to the functional resilience, the morphology of the kidney was better preserved in STN. In STN kidneys, the S3 segment of the proximal tubule, normally injured after ischemia, constitutively expressed hypoxia-inducible factor-1α (HIF-1α), which is cytoprotective in ischemia. Inducing HIF before IR improved GFR in control animals, and inhibiting the HIF target heme-oxygenase-1 before IR reduced GFR in STN animals. Taken together, these data suggest that fewer functioning nephrons in a diseased kidney do not increase the susceptibility to injury, but rather, hemodynamic and molecular adaptations in the remnant nephrons precondition them against ischemic injury.

Effects of the active components of Chinese herbal medicine Xiaoxuming Decoction on memory behavior and brain injury in rats with chronic cerebral ischemia

To study the effects of the active components of Xiaoxuming Decoction (XXM), a compound traditional Chinese herbal medicine, on chronic cerebral ischemia in rats. Chronic cerebral ischemia was induced in rats by occlusion of bilateral common carotid arteries. Then, the rats with chronic cerebral ischemia were randomly divided into five groups: model group, extract of Ginkgo biloba group and low-, medium- and high-dose active components of XXM groups. Another 11 rats without occlusion of common carotid arteries were used as the sham-operation group. Memory behavior was investigated by Morris water maze test. The structure of hippocampus and cortex neurons was observed with Nissel staining. The white matter lesion was stained with Klüver-Barrera stain method to observe the pathological changes. The astrocyte activation was observed using immunohistochemical method with glial fibrillary acidic protein (GFAP) antibody. The active components of XXM could significantly improve the impairment of learning and memory induced by chronic cerebral ischemia in rats. Compared with the model group, the time to reach the platform for rats was shortened by treating with the active components of XXM in Morris water maze test, particularly in the medium-dose group (P<0.05). In addition, the low- and medium-dose active components of XXM improved the decrease of cerebrovascular reactivity induced by chronic cerebral ischemia. The results of the pathological analysis also suggested that the active components of XXM could ameliorate the pathological damage induced by chronic cerebral ischemia in rats with the number of neurons increased, and the morphology and distribution of neurons recovered to normal levels. The low-dose active components of XXM significantly reduced the white matter lesions (P<0.05, P<0.01). Active components of XXM treatment could also reduce the activation of astrocytes. The active components of XXM may attenuate the chronic cerebral ischemic injury in rats.