Current application and future perspective of CRISPR/cas9 gene editing system mediated immune checkpoint for liver cancer treatment.

Liver cancer, which is well-known to us as one of human most prevalent malignancies across the globe, poses a significant risk to live condition and life safety of individuals in every region of the planet. It has been shown that immune checkpoint treatment may enhance survival benefits and make a significant contribution to patient prognosis, which makes it a promising and popular therapeutic option for treating liver cancer at the current time. However, there are only a very few numbers of patients who can benefit from the treatment and there also exist adverse events such as toxic effects and so on, which is still required further research and discussion. Fortunately, the clustered regularly interspaced short palindromic repeat/CRISPR-associated nuclease 9 (CRISPR/Cas9) provides a potential strategy for immunotherapy and immune checkpoint therapy of liver cancer. In this review, we focus on elucidating the fundamentals of the recently developed CRISPR/Cas9 technology as well as the present-day landscape of immune checkpoint treatment which pertains to liver cancer. What's more, we aim to explore the molecular mechanism of immune checkpoint treatment in liver cancer based on CRISPR/Cas9 technology. At last, its encouraging and powerful potential in the future application of the clinic is discussed, along with the issues that already exist and the difficulties that must be overcome. To sum up, our ultimate goal is to create a fresh knowledge that we can utilize this new CRISPR/Cas9 technology for the current popular immune checkpoint therapy to overcome the treatment issues of liver cancer.

The role of glutamate transporter-1 in the acquisition of brain ischaemic tolerance in rats induced by electro-acupuncture pre-treatment.

OBJECTIVE: To investigate whether electro-acupuncture can serve as a method of inducing brain ischaemic tolerance (BIT) by encouraging the expression of glutamate transporter-1 (GLT-1) and suppressing the release of glutamate (Glu). METHODS: Sprague-Dawley (SD) rats were divided into sham, ischaemia and EA groups. EA was performed on dazhui and baihui acupoints and the rat cerebral ischaemia model was achieved by occluding the middle cerebral artery (MCA) for 2 hours, followed by reperfusion. Dialysate was collected from the striatum in vivo to detect the concentration of Glu and the expression of Glutamate Transporter-1 (GLT-1) was examined. The changes of neurological deficit scores were evaluated at 24 hours after reperfusion, while the infarct volumes of brains were then measured with 2,3,5-triphenyltetrazolium chloride (TTC) staining. RESULTS: Compared with the ischaemia group, the concentration of Glu decreased and the expression of GLT-1 increased at most of the detective time points in the EA group; the neurological deficit scores were lower and the infarct volumes were smaller in the EA group. CONCLUSION: EA can up-regulate the expression of GLT-1 and inhibit the excessive release of Glu in the striatum in the process of subsequent ischaemic-reperfusion brain injury, which may be one of the mechanisms of inducing BIT and, thus, be neuroprotective for early ischaemic brain injury.

Exercise pretreatment promotes mitochondrial dynamic protein OPA1 expression after cerebral ischemia in rats.

Exercise training is a neuroprotective strategy in cerebral ischemic injury, but the underlying mechanisms are not yet clear. In the present study, we investigated the effects of treadmill exercise pretreatment on the expression of mitochondrial dynamic proteins. We examined the expression of OPA1/DLP1/MFF/Mfn1/Mfn2, which regulates mitochondrial fusion and fission, and cytochrome C oxidase subunits (COX subunits), which regulate mitochondrial functions, after middle cerebral artery occlusion (MCAO) in rats. T2-weighted magnetic resonance imaging (MRI) was evaluated as indices of brain edema after ischemia as well. Treadmill training pretreatment increased the expression levels of OPA1 and COXII/III/IV and alleviated brain edema, indicating that exercise pretreatment provided neuroprotection in cerebral ischemic injury via the regulation of mitochondrial dynamics and functions.

Recent research progress based on ferroptosis-related signaling pathways and the tumor microenvironment on it effects.

The existing therapies for cancer are not remote satisfactory due to drug-resistance in tumors that are malignant. There is a pressing necessity to take a step forward to develop innovative therapies that can complement current ones. Multiple investigations have demonstrated that ferroptosis therapy, a non-apoptotic modality of programmed cell death, has tremendous potential in face of multiple crucial events, such as drug resistance and toxicity in aggressive malignancies. Recently, ferroptosis at the crosswalk of chemotherapy, materials science, immunotherapy, tumor microenvironment, and bionanotechnology has been presented to elucidate its therapeutic feasibility. Given the burgeoning progression of ferroptosis-based nanomedicine, the newest advancements in this field at the confluence of ferroptosis-inducers, nanotherapeutics, along with tumor microenvironment are given an overview. Here, the signaling pathways of ferroptosis-related were first talked about briefly. The emphasis discussion was placed on the pharmacological mechanisms and the nanodrugs design of ferroptosis inducing agents based on multiple distinct metabolism pathways. Additionally, a comprehensive overview of the action mechanisms by which the tumor microenvironment influences ferroptosis was elaborately descripted. Finally, some limitations of current researches and future research directions were also deliberately discussed to provide details about therapeutic avenues for ferroptosis-related diseases along with the design of anti-drugs.

Dual-drug controllable co-assembly nanosystem for targeted and synergistic treatment of hepatocellular carcinoma.

The effectiveness of chemotherapeutic agents for hepatocellular carcinoma (HCC) is unsatisfactory because of tumor heterogeneity, multidrug resistance, and poor target accumulation. Therefore, multimodality-treatment with accurate drug delivery has become increasingly popular. Herein, a cell penetrating peptide-aptamer dual modified-nanocomposite (USILA NPs) was successfully constructed by coating a cell penetrating peptide and aptamer onto the surface of sorafenib (Sora), ursolic acid (UA) and indocyanine green (ICG) condensed nanodrug (USI NPs) via one-pot assembly for targeted and synergistic HCC treatment. USILA NPs showed higher cellular uptake and cytotoxicity in HepG2 and H22 cells, with a high expression of epithelial cell adhesion molecule (EpCAM). Furthermore, these NPs caused more significant mitochondrial membrane potential reduction and cell apoptosis. These NPs could selectively accumulate at the tumor site of H22 tumor-bearing mice and were detected with the help of ICG fluorescence; moreover, they retarded tumor growth better than monotherapy. Thus, USILA NPs can realize the targeted delivery of dual drugs and the integration of diagnosis and treatment. Moreover, the effects were more significant after co-administration of iRGD peptide, a tumor-penetrating peptide with better penetration promoting ability or programmed cell death ligand 1 (PD-L1) antibody for the reversal of the immunosuppressive state in the tumor microenvironment. The tumor inhibition rates of USILA NPs + iRGD peptide or USILA NPs + PD-L1 antibody with good therapeutic safety were 72.38 % and 67.91 % compared with control, respectively. Overall, this composite nanosystem could act as a promising targeted tool and provide an effective intervention strategy for enhanced HCC synergistic treatment.

Cortical reorganization after motor imagery training in chronic stroke patients with severe motor impairment: a longitudinal fMRI study.

INTRODUCTION: Despite its clinical efficacy, few studies have examined the neural mechanisms of motor imagery training (MIT) in stroke. Our objective was to find the cortical reorganization patterns after MIT in chronic stroke patients. METHODS: Twenty stroke patients with severe motor deficits were randomly assigned to the MIT or conventional rehabilitation therapy (CRT) group, but two lost in the follow-up. All 18 patients received CRT 5 days/week for 4 weeks. Nine subjects in the MIT group received 30-min MIT 5 days/week for 4 weeks. Before and after the interventions, the upper limb section of the Fugl-Meyer Scale (FM-UL) was blindly evaluated, and functional magnetic resonance imaging was administered while the patients executed a passive fist clutch task. RESULTS: Two cortical reorganization patterns were found. One pattern consisted of the growth in activation in the contralateral sensorimotor cortex (cSMC) for most patients (six in the MIT group, five in the CRT group), and the other consisted of focusing of the activation in the cSMC with increasing of the laterality index of the SMC for a small portion of patients (three in the MIT group, one in the CRT group). When we applied correlation analyses to the variables of relative ΔcSMC and ΔFM-UL in the 11 patients who experienced the first pattern, a positive relationship was detected. CONCLUSIONS: Our results indicate that different cortical reorganization patterns (increases in or focusing of recruitment to the cSMC region) exist in chronic stroke patients after interventions, and patients may choose efficient patterns to improve their motor function.

Early exercise improves cerebral blood flow through increased angiogenesis in experimental stroke rat model.

BACKGROUND: Early exercise after stroke promoted angiogenesis and increased microvessles density. However, whether these newly formatted vessels indeed give rise to functional vascular and improve the cerebral blood flow (CBF) in impaired brain region is still unclear. The present study aimed to determine the effect of early exercise on angiogenesis and CBF in ischemic region. METHODS: Adult male Sprague Dawley rats were subjected to 90 min middle cerebral artery occlusion(MCAO)and randomly divided into early exercise and non-exercised control group 24 h later. Two weeks later, CBF in ischemic region was determined by laser speckle flowmetry(LSF). Meantime, micro vessels density, the expression of tie-2, total Akt and phosphorylated Akt (p-Akt), and infarct volume were detected with immunohistochemistry, 2,3,5 triphenyltetrazolium chloride (TTC) staining and western blotting respectively. The function was evaluated by seven point's method. RESULTS: Our results showed that CBF, vessel density and expression of Tie-2, p-Akt in ischemic region were higher in early exercise group compared with those in non-exercise group. Consistent with these results, rats in early exercise group had a significantly reduced infarct volume and better functional outcomes than those in non-exercise group. CONCLUSIONS: Our results indicated that early exercise after MCAO improved the CBF in ischemic region, reduced infarct volume and promoted the functional outcomes, the underlying mechanism was correlated with angiogenesis in the ischemic cortex.

Demonstration of posturographic parameters of squat-stand activity in hemiparetic patients on a new multi-utility balance assessing and training system.

BACKGROUND: Quantitative evaluation of position control ability in stroke patients is needed. Here we report a demonstration of position control ability assessment and test-retest reliability during squat-stand activity on a new system in hemiparetic patients and controls. METHODS: Sixty-two healthy adults and thirty-four hemiparetics were enrolled. RESULTS: During partial weight support, the ICCs ranged from 0.77 to 0.91, which indicated a good reliability. During standard weight bearing and resistance, the ICCs varied from 0.64 to 0.86 and 0.54 to 0.84, respectively, indicating a fair reliability. Compared with the healthy adults, the stroke patients demonstrated poorer position control ability. CONCLUSIONS: The posturography of the squat-stand activity is a new and reliable measurement tool for position control. According to the methods proposed here, hemiparetics can be differentiated from healthy adults using the squat-stand activity. This activity will provide a new evaluation tool and therapy with visual feedback for the stroke patients. TRIAL REGISTRATION: Chinese clinical trial registry, ChiCTR-TRC-10000863.

Early Exercise Protects against Cerebral Ischemic Injury through Inhibiting Neuron Apoptosis in Cortex in Rats.

Early exercise is an effective strategy for stroke treatment, but the underlying mechanism remains poorly understood. Apoptosis plays a critical role after stroke. However, it is unclear whether early exercise inhibits apoptosis after stroke. The present study investigated the effect of early exercise on apoptosis induced by ischemia. Adult SD rats were subjected to transient focal cerebral ischemia by middle cerebral artery occlusion model (MCAO) and were randomly divided into early exercise group, non-exercise group and sham group. Early exercise group received forced treadmill training initiated at 24 h after operation. Fourteen days later, the cell apoptosis were detected by TdT-mediated dUTP-biotin nick-end labeling (TUNEL) and Fluoro-Jade-B staining (F-J-B). Caspase-3, cleaved caspase-3 and Bcl-2 were determined by western blotting. Cerebral infarct volume and motor function were evaluated by cresyl violet staining and foot fault test respectively. The results showed that early exercise decreased the number of apoptotic cells (118.74 ± 6.15 vs. 169.65 ± 8.47, p < 0.05, n = 5), inhibited the expression of caspase-3 and cleaved caspase-3 (p < 0.05, n = 5), and increased the expression of Bcl-2 (p < 0.05, n = 5). These data were consistent with reduced infarct volume and improved motor function. These results suggested that early exercise could provide neuroprotection through inhibiting neuron apoptosis.

The effect of different intensities of treadmill exercise on cognitive function deficit following a severe controlled cortical impact in rats.

Exercise has been proposed for the treatment of traumatic brain injury (TBI). However, the proper intensity of exercise in the early phase following a severe TBI is largely unknown. To compare two different treadmill exercise intensities on the cognitive function following a severe TBI in its early phase, rats experienced a controlled cortical impact (CCI) and were forced to treadmill exercise for 14 days. The results revealed that the rats in the low intensity exercise group had a shorter latency to locate a platform and a significantly better improvement in spatial memory in the Morris water maze (MWM) compared to the control group (p < 0.05). The high intensity exercise group showed a longer latency and a mild improvement in spatial memory compared to the control group rats in the MWM; however, this difference was not statistically significant (p > 0.05). The brain-derived neurotrophic factor (BDNF) and p-CREB protein levels in the contralateral hippocampus were increased significantly in the low intensity exercise group. Our results suggest that 2 weeks of low intensity of treadmill exercise is beneficial for improving cognitive function and increasing hippocampal BDNF expression after a severe TBI in its early phase.

Early exercise protects the blood-brain barrier from ischemic brain injury via the regulation of MMP-9 and occludin in rats.

Early exercise within 24 h after stroke can reduce neurological deficits after ischemic brain injury. However, the mechanisms underlying this neuroprotection remain poorly understood. Ischemic brain injury disrupts the blood-brain barrier (BBB) and then triggers a cascade of events, leading to secondary brain injury and poor long-term outcomes. This study verified the hypothesis that early exercise protected the BBB after ischemia. Adult rats were randomly assigned to sham, early exercise (EE) or non-exercise (NE) groups. The EE and NE groups were subjected to ischemia induced by middle cerebral artery occlusion (MCAO). The EE group ran on a treadmill beginning 24 h after ischemia, 30 min per day for three days. After three-days' exercise, EB extravasation and electron microscopy were used to evaluate the integrity of the BBB. Neurological deficits, cerebral infarct volume and the expression of MMP-9, the tissue inhibitors of metalloproteinase-1 (TIMP-1), and occludin were determined. The data indicated that early exercise significantly inhibited the ischemia-induced reduction of occludin, and an increase in MMP-9 promoted TIMP-1 expression (p < 0.01), attenuated the BBB disruption (p < 0.05) and neurological deficits (p < 0.01) and diminished the infarct volume (p < 0.01). Our results suggest that the neuroprotection conferred by early exercise was likely achieved by improving the function of the BBB via the regulation of MMP-9 and occludin.

Shear stress inhibits apoptosis of ischemic brain microvascular endothelial cells.

As a therapeutic strategy for ischemic stroke, to restore or increase cerebral blood flow (CBF) is the most fundamental option. Laminar shear stress (LS), as an important force generated by CBF, mainly acts on brain microvascular endothelial cells (BMECs). In order to study whether LS was a protective factor in stroke, we investigated LS-intervented ischemic apoptosis of rat BMECs (rBMECs) through PE Annexin V/7-AAD, JC-1 and Hoechst 33258 staining to observe the membranous, mitochondrial and nuclear dysfunction. Real-time PCR and western blot were also used to test the gene and protein expressions of Tie-2, Bcl-2 and Akt, which were respectively related to maintain membranous, mitochondrial and nuclear norm. The results showed that LS could be a helpful stimulus for ischemic rBMECs survival. Simultaneously, membranous, mitochondrial and nuclear regulation played an important role in this process.

The effects of exercise intensity on p-NR2B expression in cerebral ischemic rats.

BACKGROUND: The current study explored the effects of treadmill exercise intensity on functional recovery and hippocampal phospho-NR2B (p-NR2B) expression in cerebral ischemic rats, induced by permanent middle cerebral artery occlusion (MCAO) surgery. METHOD: Adult male Sprague-Dawley rats were randomly divided into four groups, including sham, no exercise (NE), low intensity training (LIT, v = 15 m/min), and moderate intensity training groups (MIT, v = 20 m/min). At different time points, the hippocampal expressions of p-NR2B and total NR2B were examined. In addition, neurological deficit score (NDS), body weight, and 2,3,5-triphenyltetrazolium chloride (TTC) staining were used to evaluate brain infarct volume as assessments of post-stroke functional recovery. In order to investigate the effect of exercise on survival, the mortality rate was also recorded. RESULTS: The results showed that treadmill exercise significantly decreased hippocampal expression of p-NR2B but didn't change the total NR2B, compared to the NE group on the 3rd, 7th, and 14th days following MCAO surgery. The effect on changes in p-NR2B levels, body weight, and brain infarct volume were more significant in the LIT compared to the MIT group. DISCUSSION AND CONCLUSION: The current findings demonstrate that physical exercise can produce neuroprotective effects, in part by down-regulating p-NR2B expression. Furthermore, the appropriate intensity of physical exercise is critical for post-stroke rehabilitation.

Early exercise affects mitochondrial transcription factors expression after cerebral ischemia in rats.

Increasing evidence shows that exercise training is neuroprotective after stroke, but the underlying mechanisms are unknown. To clarify this critical issue, the current study investigated the effects of early treadmill exercise on the expression of mitochondrial biogenesis factors. Adult rats were subjected to ischemia induced by middle cerebral artery occlusion followed by reperfusion. Expression of two genes critical for transcriptional regulation of mitochondrial biogenesis, peroxisome proliferator-activated receptor coactivator-1 (PGC-1) and nuclear respiratory factor-1 (NRF-1), were examined by RT-PCR after five days of exercise starting at 24 h after ischemia. Mitochondrial protein cytochrome C oxidase subunit IV (COX IV) was detected by Western blot. Neurological status and cerebral infarct volume were evaluated as indices of brain damage. Treadmill training increased levels of PGC-1 and NRF-1 mRNA, indicating that exercise promotes rehabilitation after ischemia via regulation of mitochondrial biogenesis.

Pre-ischemic treadmill training for prevention of ischemic brain injury via regulation of glutamate and its transporter GLT-1.

Pre-ischemic treadmill training exerts cerebral protection in the prevention of cerebral ischemia by alleviating neurotoxicity induced by excessive glutamate release following ischemic stroke. However, the underlying mechanism of this process remains unclear. Cerebral ischemia-reperfusion injury was observed in a rat model after 2 weeks of pre-ischemic treadmill training. Cerebrospinal fluid was collected using the microdialysis sampling method, and the concentration of glutamate was determined every 40 min from the beginning of ischemia to 4 h after reperfusion with high-performance liquid chromatography (HPLC)-fluorescence detection. At 3, 12, 24, and 48 h after ischemia, the expression of the glutamate transporter-1 (GLT-1) protein in brain tissues was determined by Western blot respectively. The effect of pre-ischemic treadmill training on glutamate concentration and GLT-1 expression after cerebral ischemia in rats along with changes in neurobehavioral score and cerebral infarct volume after 24 h ischemia yields critical information necessary to understand the protection mechanism exhibited by pre-ischemic treadmill training. The results demonstrated that pre-ischemic treadmill training up-regulates GLT-1 expression, decreases extracellular glutamate concentration, reduces cerebral infarct volume, and improves neurobehavioral score. Pre-ischemic treadmill training is likely to induce neuroprotection after cerebral ischemia by regulating GLT-1 expression, which results in re-uptake of excessive glutamate.

[Effects of early application of Tuina treatment on quadriceps surface myoelectricity in patients after total knee arthroplasty: a randomized controlled trial].

BACKGROUND: Total knee replacement surgery is commonly used in end-stage diseases of the knee. It is important for improving surgical efficacy and patient satisfaction by promoting early rehabilitation of patients and improving knee function. OBJECTIVE: To observe the effects of early application of Tuina treatment on quadriceps surface electromyography (EMG) in patients with rheumatoid arthritis having undergone total knee arthroplasty. DESIGN, SETTING, PARTICIPANTS AND INTERVENTION: The study was performed at the Orthopedic Department of Huashan Hospital, Fudan University, and the Shanghai Guanghua Hospital of Integrated Traditional Chinese and Western Medicine from June 2010 to September 2011. A total of 66 patients with rheumatoid arthritis who had undergone total knee replacement surgery were randomly divided into control group and observation group, 33 cases in each. The patients in the control group were administered with continuous passive training (CPM), and the patients in the observation group were treated with CPM combined with Tuina, from prior surgery to four weeks post-surgery. MAIN OUTCOME MEASURES: The knee function was evaluated using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) questionnaire at baseline and 4 weeks after the surgery. Quadriceps surface EMG was also detected at the same time points. RESULTS: After 4 weeks of Tuina and comprehensive rehabilitation intervention, the WOMAC questionnaire score of the observation group was decreased compared with the control group (P<0.01); median frequency and integrated electromyography of the rectus femoris and vastus medialis muscles, which were recorded by EMG, in the observation group were higher than those in the control group (P<0.01). CONCLUSION: Tuina can improve the recovery of patients who have undergone total knee replacement by increasing quadriceps EMG.

Exercise improves recovery after ischemic brain injury by inducing the expression of angiopoietin-1 and Tie-2 in rats.

Post-ischemia angiogenesis plays a critical part in the recovery of neural networks. Angiopoietin (Ang) has received much attention recently due to its key role in neurovascular remodeling. Exercise is proved to contribute to angiogenesis in normal or injured human skeletal muscle. The therapeutic effect of exercise on central angiogenesis after cerebral ischemia, however, has not been studied. In the present study, we investigated the relationship between exercise and the expression of Ang-1, Ang-2, and Tie-2 receptor tyrosine kinase in the brain using a rat model of stroke, with right middle cerebral artery occluded (MCAO). Male Sprague-Dawley rats were randomly grouped (n = 12): stroke-exercise (SE), stroke-no exercise (SNE) and sham-no exercise (SHAM). The SE group ran on a treadmill at a speed of 12 m/min, 30 min/day for 2 weeks. Functional recovery was assessed with neurological evaluation scores. Brain infarction was measured by Nissl staining. Expression of Ang-1, Ang-2, and Tie-2 were compared by immunohistochemical and real-time PCR analyses. The infarct volume in the SE group was significantly reduced compared with the SNE group (p < 0.05). Ang-1 (p < 0.05) and Tie-2 (p < 0.05) and their mRNA expression (p < 0.01 and p < 0.05, respectively) were increased in SE animals at 2 weeks, whereas Ang-2 expression remained unchanged. In conclusion, enhanced expression of Ang-1 and Tie-2 by exercise improves recovery of brain function in MCAO rats. Our results suggest the importance of angiogenesis in rehabilitation for post-ischemia brain injury and help to explain the underlying mechanism.

Treadmill pre-training suppresses the release of glutamate resulting from cerebral ischemia in rats.

This study was designed to investigate the neuroprotective effect of treadmill pre-training against the over-release of glutamate resulting from cerebral ischemia. Sprague-Dawley rats underwent 2 weeks of treadmill run-training before cerebral ischemia was performed by middle cerebral artery occlusion. The level of glutamate in brain extracellular fluid was detected before, during and after ischemia/reperfusion. The expression of metabotropic glutamate receptor-1 (mGluR1) mRNA in striatum was examined after ischemia for 80 min and reperfusion for 240 min. Neurological defect score and brain infarction volumes were measured. The treadmill pre-training significantly suppressed the release of glutamate, and reduced the expression of mGluR1 mRNA at 59% (P < 0.01) and 62% (P < 0.05), respectively, as compared with the ischemia group. The neurological defect score and infarction volume were significantly improved by 75% (P < 0.01) and 74% (P < 0.01), respectively, in the pre-training group, as compared to the ischemia group. Treadmill pre-training has a significant neuroprotective function against ischemia/reperfusion injury, by suppressing glutamate release resulting from cerebral ischemia, and this effect may be mediated by downregulation of mGluR1.

The effect of treadmill training pre-exercise on glutamate receptor expression in rats after cerebral ischemia.

Physical exercise has been demonstrated to be neuroprotective in both clinical and laboratory settings. However, the exact mechanism underlying this effect is unclear. Our study aimed to investigate whether pre-ischemic treadmill training could serve as a form of ischemic preconditioning in a rat model undergoing middle cerebral artery occlusion (MCAO). Thirty-six rats were divided into three groups: a sham control group, a non-exercise with operation group and an exercise with operation group. After treadmill training, ischemia was induced by occluding the MCA for 2 h, followed by reperfusion. Half of the rats in each group were sacrificed for mRNA detection of mGluR5 and NR2B 80 min after occlusion. The remaining animals were evaluated for neurological deficits by behavioral scoring and then decapitated to assess the infarct volume. The mRNA expression of mGluR5 and NR2B was detected by real-time PCR. The results suggest that pre-ischemic treadmill training may induce brain ischemic tolerance by reducing the mRNA levels of mGluR5 and NR2B, and thus, the results indicate that physical exercise might be an effective method to establish ischemic preconditioning.

Pre-ischemic treadmill training induces tolerance to brain ischemia: involvement of glutamate and ERK1/2.

Physical exercise has been shown to be beneficial in stroke patients and animal stroke models. However, the exact mechanisms underlying this effect are not yet very clear. The present study investigated whether pre-ischemic treadmill training could induce brain ischemic tolerance (BIT) by inhibiting the excessive glutamate release and event-related kinase 1/2 (ERK1/2) activation observed in rats exposed to middle cerebral artery occlusion (MCAO). Sprague-Dawley rats were divided into three groups (n = 12/group): sham surgery without prior exercise, MCAO without prior exercise and MCAO following three weeks of exercise. Pre-MCAO exercise significantly reduced brain infarct size (103.1 +/- 6.7 mm3) relative to MCAO without prior exercise (175.9 +/- 13.5 mm3). Similarly, pre-MCAO exercise significantly reduced neurological defects (1.83 +/- 0.75) relative to MCAO without exercise (3.00 +/- 0.63). As expected, MCAO increased levels of phospho-ERK1/2 (69 +/- 5%) relative to sham surgery (40 +/- 5%), and phospho-ERK1/2 levels were normalized in rats exposed to pre-ischemic treadmill training (52 +/- 6%) relative to MCAO without exercise (69% +/- 5%). Parallel effects were observed on striatal glutamate overflow. This study suggests that pre-ischemic treadmill training might induce neuroprotection by inhibiting the phospho-ERK1/2 over-activation and reducing excessive glutamate release.