Mechanism of inflammatory response and therapeutic effects of stem cells in ischemic stroke:current evidence and future perspectives

Ischemic stroke is a leading cause of death and disability worldwide,with an increasing trend and tendency for onset at a younger age.China,in particular,bears a high burden of stroke cases.In recent years,the inflammatory response after stroke has become a research hotspot:understanding the role of inflammatory response in tissue damage and repair following ischemic stroke is an important direction for its treatment.This review summarizes several major cells involved in the inflammatory response following ischemic stroke,including microglia,neutrophils,monocytes,lymphocytes,and astrocytes.Additionally,we have also highlighted the recent progress in various treatments for ischemic stroke,particularly in the field of stem cell therapy.Overall,understanding the complex interactions between inflammation and ischemic stroke can provide valuable insights for developing treatment strategies and improving patient outcomes.Stem cell therapy may potentially become an important component of ischemic stroke treatment.

Association of DNA methylation/demethylation with the functional outcome of stroke in a hyperinflammatory state

Inflammation is closely related to stroke prognosis, and high inflammation status leads to poor functional outcome in stroke. DNA methylation is involved in the pathogenesis and prognosis of stroke. However, the effect of DNA methylation on stroke at high levels of inflammation is unclear. In this study, we constructed a hyperinflammatory cerebral ischemia mouse model and investigated the effect of hypomethylation and hypermethylation on the functional outcome. We constructed a mouse model of transient middle cerebral artery occlusion and treated the mice with lipopolysaccharide to induce a hyperinflammatory state. To investigate the effect of DNA methylation on stroke, we used small molecule inhibitors to restrain the function of key DNA methylation and demethylation enzymes. 2,3,5-Triphenyltetrazolium chloride staining, neurological function scores, neurobehavioral tests, enzyme-linked immunosorbent assay, quantitative reverse transcription PCR and western blot assay were used to evaluate the effects after stroke in mice. We assessed changes in the global methylation status by measuring DNA 5-mc and DNA 5-hmc levels in peripheral blood after the use of the inhibitor. In the group treated with the DNA methylation inhibitor, brain tissue 2,3,5-triphenyltetrazolium chloride staining showed an increase in infarct volume, which was accompanied by a decrease in neurological scores and worsening of neurobehavioral performance. The levels of inflammatory factors interleukin 6 and interleukin-1 beta in ischemic brain tissue and plasma were elevated, indicating increased inflammation. Related inflammatory pathway exploration showed significant overactivation of nuclear factor kappa B. These results suggested that inhibiting DNA methylation led to poor functional outcome in mice with high inflammation following stroke. Further, the effects were reversed by inhibition of DNA demethylation. Our findings suggest that DNA methylation regulates the inflammatory response in stroke and has an important role in the functional outcome of hyperinflammatory stroke.

A growth-regulating factor 7(GRF7)-mediated gene regulatory network promotes leaf growth and expansion in sugarcane

Knowledge of the function of growth-regulating factors(GRFs)in sugarcane(Saccharum officinarum and S.spontaneum)growth and development could assist breeders in selecting desirable plant architectures.However,limited information about GRFs is available in Saccharum due to their polyploidy.In this study,22 GRFs were identified in the two species and their conserved domains,gene structures,chromosome location,and synteny were characterized.GRF7 expression varied among tissues and responded to diurnal rhythm.SsGRF7-YFP was localized preferentially in the nucleus and appears to act as a transcriptional cofactor.SsGRF7 positively regulated the size and length of rice leaves,possibly by regulating cell size and plant hormones.Of seven potential transcription factors binding to the SsGRF7 promoter in S.spontaneum,four showed positive expression patterns,and two showed negative expression patterns relative to SsGRF7.

Immunotherapeutic hydrogel for co-delivery of STAT3 siRNA liposomes and lidocaine hydrochloride for postoperative comprehensive management of NSCLC in a single application

Despite standard treatment for non-small cell lung cancer(NSCLC)being surgical resection,cancer recurrence and complications,such as induction of malignant pleural effusion(MPE)and significant postoperative pain,usually result in treatment failure.In this study,an alginate-based hybrid hydrogel(SOG)is developed that can be injected into the resection surface of the lungs during surgery.Briefly,endoplasmic reticulum-modified liposomes(MSLs)pre-loaded with the signal transducer and activator of transcription 3(STAT3)small interfering RNA and lidocaine hydrochloride are encapsulated in SOG.Once applied,MSLs strongly downregulated STAT3 expression in the tumor microenvironment,resulting in the apoptosis of lung cancer cells and polarization of tumor-associated macrophages towards the M1-like phenotype.Meanwhile,the release of lidocaine hydrochloride(LID)was beneficial for pain relief and natural killer cell activation.Our data demonstrated MSL@LID@SOG not only efficiently inhibited tumor growth but also potently improved the quality of life,including reduced MPE volume and pain relief in orthotopic NSCLC mouse models,even with a single administration.MSL@LID@SOG shows potential for comprehensive clinical management upon tumor resection in NSCLC,and may alter the treatment paradigms for other cancers.

Thrombin increases the expression of cholesterol 25-hydroxylase in rat astrocytes after spinal cord injury

Astrocytes are important cellular centers of cholesterol synthesis and metabolism that help maintain normal physiological function at the organism level.Spinal cord injury results in aberrant cholesterol metabolism by astrocytes and excessive production of oxysterols,which have profound effects on neuropathology.25-Hydroxycholesterol(25-HC),the main product of the membrane-associated enzyme cholesterol-25-hydroxylase(CH25H),plays important roles in mediating neuroinflammation.However,whether the abnormal astrocyte cholesterol metabolism induced by spinal cord injury contributes to the production of 25-HC,as well as the resulting pathological effects,remain unclear.In the present study,spinal cord injury-induced activation of thrombin was found to increase astrocyte CH25H expression.A protease-activated receptor 1 inhibitor was able to attenuate this effect in vitro and in vivo.In cultured primary astrocytes,thrombin interacted with protease-activated receptor 1,mainly through activation of the mitogen-activated protein kinase/nuclear factor-kappa B signaling pathway.Conditioned culture medium from astrocytes in which ch25h expression had been knocked down by siRNA reduced macrophage migration.Finally,injection of the protease activated receptor 1 inhibitor SCH79797 into rat neural sheaths following spinal cord injury reduced migration of microglia/macrophages to the injured site and largely restored motor function.Our results demonstrate a novel regulatory mechanism for thrombin-regulated cholesterol metabolism in astrocytes that could be used to develop anti-inflammatory drugs to treat patients with spinal cord injury.

Residence time distribution of high viscosity fluids falling film flow down outside of industrial-scale vertical wavy wall: Experimental investigation and CFD prediction

The flow behavior of gravity-driven falling film of non-conductive high viscosity polymer fluids on an industrial-scale vertical wavy wall was investigated in terms of film thickness and residence time distribution by numerical simulation and experiment.Falling film flow of high viscosity fluids was found to be steady on a vertical wavy wall in the presence of the large film thickness.The comparison between numerical simulation and experiment for the film thickness both in crest and trough of wavy wall showed good agreement.The simulation results of average residence time of falling film flow with different viscous fluids were also consistent with the experimental results.This work provides the initial insights of how to evaluate and optimize the falling film flow system of polymer fluid.

Mechanosignaling activation of TGFβmaintains intervertebral disc homeostasis

Intervertebral disc （IVD） degeneration is the leading cause of disability with no disease-modifying treatment. IVD degeneration is associated with instable mechanical loading in the spine, but little is known about how mechanical stress regulates nucleus notochordal （NC） cells to maintain IVD homeostasis. Here we report that mechanical stress can result in excessive integrin αvβ6-mediated activation of transforming growth factor beta （TGFβ）, decreased NC cell vacuoles, and increased matrix proteoglycan production, and results in degenerative disc disease （DDD）. Knockout of TGFβ type II receptor （TβRII） or integrin αv in the NC cells inhibited functional activity of postnatal NC cells and also resulted in DDD under mechanical loading. Administration of RGD peptide, TGFβ, and αvβ6-neutralizing antibodies attenuated IVD degeneration. Thus, integrin-mediated activation of TGFβ plays a critical role in mechanical signaling transduction to regulate IVD cell function and homeostasis. Manipulation of this signaling pathway may be a potential therapeutic target to modify DDD.

Utilization of longitudinal ultrasound to quantify joint soft-tissue changes in a mouse model of posttraumatic osteoarthritis

To assess the utility of longitudinal ultrasound （US） to quantify volumetric changes in joint soft tissues during the progression of posttraumatic osteoarthritis （PTOA） in mice, and validate the US results with histological findings. A longitudinal cohort of 3-month-old wild-type C57BL/6 male mice received the Hulth-Telhag surgical procedure on right knee to induce ~OA, and sham surgery on their left knee as control. US scans were performed on both knees before, 2, 4, 6, and 8 weeks post-surgery. Joint space volume and Power-Doppler （PD） volume were obtained from US images via Amira software. A paraUel cross-sectional cohort of mice was killed at each US time point, and knee joints were subjected to histological analysis to obtain synovial soft-tissue area and OARSI scores. The correlation between US joint space volume and histological synovial soft-tissue area or OARSI score was assessed via linear regression analysis. US images indicated increased joint space volume in PTOA joints over time, which was associated with synovial inflammation and cartilage damage by histology. These changes started from 2 weeks post-surgery and gradually became more severe. No change was detected in sham joints. Increased joint space volume was significantly correlated with increased synovial soft-tissue area and the OARSI score （P 〈 0.001）. PD signal was detected in the joint space of PTOA joints at 6 weeks post-surgery, which was consistent with the location of blood vessels that stained positively for CD31 and alpha-smooth muscle actin in the synovium. This study indicates that US is a cost-effective longitudinal outcome measure of volumetric and vascular changes in joint soft tissues during PTOA progression in mice, which positively correlates with synovial inflammation and cartilage damage.

Rapid transfer alignment for SINS of carrier craft

In order to improve the survival ability and rapid response ability of the carrier craft,a new rapid transfer alignment method of the strapdown inertial navigation system（SINS） on a rocking base is put forward.In the method,the aircraft carrier does not need any form of movement.Meantime,interfering motions such as rolling,pitching,and yawing motions caused by sea waves are effectively used.Firstly,the deck flexure deformation model is made.Secondly,the state space model of transfer alignment is presented.Finally,the feasibility of this method is validated by the simulation.Simulation results show that the misalignment angle error can be estimated and reach an anticipated precision-0.2 mrad in 5 s,while the deck deformation angle error can be estimated and reach a better precision- 0.1 mrad in 20 s.

Can semipermeable membranes coating materials influence in vivo performance for paliperidone tri-layer ascending release osmotic pump tablet:In vitro evaluation and in vivo pharmacokinetics study

One purpose of this study was to develop a paliperidone(PAL)tri-layer ascending release pushepull osmotic pump(TA-PPOP)tablet which could meet the needs of clinical applications.And another purpose was to investigate whether different coating materials influenced in vivo performance of TA-PPOP.The ascending release mechanism of this trilayer delivery system on theory was elaborated.TA-PPOP was prepared by means of coating with cellulose acetate(CA)or ethyl cellulose(EC).Several important influence factors such as different core tablet compositions and different coating solution ingredients involved in the formulation procedure were investigated.The optimization of formulation and process was conducted by comparing different in vitro release behaviors of PAL.In vitro dissolution studies indicated that both the two formulations of different coating materials were able to deliver PAL at an ascending release rate during the whole 24 h test.The in vivo pharmacokinetics study showed that both self-made PPOP tablets with different coating had a good in vitro-in vivo correlation(IVIVC)and were bioequivalent with the brand product,which demonstrated no significant influence of the coating materials on the in vivo release acceleration of TA-PPOP.

Ratiometric delivery of doxorubicin and berberine by liposome enables superior therapeutic index than Doxil?

Although the appearance of Doxil alleviated the cardiotoxicity of DOX, the progression-free survival of patients was not prolonged compared with traditional medication regimens, and side effects such as hand-foot syndrome has occurred. In order to solve this dilemma, we have designed a novel co-delivery strategy to construct a co-loaded liposome of berberine(BER) and doxorubicin(DOX), which was called Lipo Be Do. The optimal synergistic ratio of the two drugs was screened by cell cytotoxicity experiments in vitro, and the optimal attenuation ratio was further determined by in vivo cardiac H&E staining pathological sections. The optimal combination treatment caused a robust increase in apoptotic cells of 4T1, as compared to drug alone treatment. The prepared co-loaded liposome, Lipo Be Do, had high encapsulation efficiency and good stability. The nanoliposome carrier controlled the biological fate of the drugs and maintained a pre-defined optimal ratio in vivo. The Lipo Be Do significantly inhibited tumor growth in 4T1 murine mammary carcinoma model compared with Doxil(P < 0.05), and completely overcame the myocardial rupture toxicity caused by Doxil in mice. Our co-loaded liposome delivery platform technology provided a new direction for the clinical treatment of triple-negative breast cancer and the safe application of DOX.

Development of a method to quantify total and free irinotecan and 7-ethyl-10-hydroxycamptothecin(SN-38) for pharmacokinetic and bio-distribution studies after administration of irinotecan liposomal formulation

In 2015,liposomal formulation of irinotecan(ONIVYDE)has been approved by FDA and widely applied in the treatment of pancreatic cancer.ONIVYDE is a novel liposome formulation,entrapping CPT-11 in the aqueous core of vesicles using a modified gradient loading method.Due to toxicity concerns,it is essential to explore a rapid and reliable method to effectively isolate and quantify the non-liposomal,namely,free CPT-11and total CPT-11 in plasma.This study focuses on separation of non-liposomal CPT-11,evaluation of the pharmacokinetics of free CPT-11 and total CPT-11 and bio-distribution after intravenous administration of CPT-11 liposome.Free CPT-11 in plasma was separated by solid-phase extraction(SPE).The amount of total CPT-11 and main metabolite 7-ethyl-10-hydroxycamptothecin(SN-38)in plasma was quantified by ultra-performance liquid chromatography–MS/MS.The calibration curves fitted well and lower limit of quantitation for SN-38,free CPT-11,total CPT-11 and CPT-11 in tissue and were 5 ng/ml,10 ng/ml,4.44 ng/ml and 25 ng/ml respectively.The recoveries,precision and accuracy of the method appear satisfactory.Using this method,the pharmacokinetics and bio-distribution of CPT-11 liposome formulation after an intravenous dose of 2.5 mg/kg were then investigated.

Mash1 efficiently reprograms rat astrocytes into neurons

To date, it remains poorly understood whether astrocytes can be easily reprogrammed into neurons. Mashl and Brn2 have been previously shown to cooperate to reprogram fibroblasts into neurons. In this study, we examined astrocytes from 2-month-old Sprague-Dawley rats, and found that Brn2 was expressed, but Mashl was not detectable. Thus, we hypothesized that Mashl alone could be used to reprogram astrocytes into neurons. We transfected a recombinant MSCV-MASH1 plasmid into astrocytes for 72 hours, and saw that all cells expressed Mashl. One week later, we observed the changes in morphology of astrocytes, which showed typical neuro- nal characteristics. Moreover, β-tubulin expression levels were significantly higher in astrocytes expressing Mashl than in control cells. These results indicate that Mashl alone can reprogram astrocytes into neurons.

Impact of the amount of PEG on prodrug nanoassemblies for efficient cancer therapy

PEGylation has been widely used to improve the pharmacokinetic properties of prodrug self-assembled nanoparticles(prodrug-SANPs).However,the impacts of the amount of PEG on the self-assemble stability,cellular uptake,pharmacokinetics,and antitumor efficacy of prodrug-SANPs are still unknown.Herein,selenoether bond bridged docetaxel dimeric prodrug was synthesized as the model prodrug.Five prodrug-SANPs were designed by using different mass ratios of prodrugs to PEG(W_(prodrug)/W_(DSPE-mPEG2000)=10:0,9:1,8:2,7:3 and 6:4),and defined as Pure drug NPs,9:1NPs,8:2NPs,7:3 NPs and 6:4 NPs,respectively.Interestingly,8:2 NPs formed the most compact nanostructure,thus improving the self-assemble stability and pharmacokinetics behavior.In addition,the difference of these prodrug-SANPs in cellular uptake was investigated,and the influence of PEG on cytotoxicity and antitumor efficacy was also clarified in details.The 8:2 NPs exhibited much better antitumor efficacy than other prodrug-SANPs and even commercial product.Our findings demonstrated the pivotal role of the amount of PEG on prodrug-SANPs.

Developmental Temporal Patterns and Molecular Network Features in the Transcriptome of Rat Spinal Cord

The molecular network features of spinal cord development that are integral to tissue engineering remain poorly understood in placental mammals,especially in terms of their relationships with vital biological processes such as regeneration.Here,using a large-scale temporal transcriptomic analysis of rat spinal cord from the embryonic stage to adulthood,we show that fluctuating RNA expression levels reflect highly active transcriptional regulation,which may initiate spinal cord patterning.We also demonstrate that microRNAs(miRNAs)and transcriptional factors exhibit a mosaic profile based on their expression patterns,while differential alternative splicing events reveal that alternative splicing may be a driving force for the development of the node of Ranvier.Our study also supports the existence of a negative correlation between innate immunity and intrinsic growth capacity.Epigenetic modifications appear to perform their respective regulatory functions at different stages of development,while guanine nucleotidebinding protein(G protein)-coupled receptors(including olfactory receptors(ORs))may perform pleiotropic roles in axonal growth.This study provides a valuable resource for investigating spinal cord development and complements the increasing number of single-cell datasets.These findings also provide a genetic basis for the development of novel tissue engineering strategies.

Inhibition of Axinl in osteoblast precursor cells leads to defects in postnatal bone growth through suppressing osteoclast formation

Axinl is a negative regulator of β-catenin signaling and its role in osteoblast precursor cells remains undefined.In the present studies,we determined changes in postnatal bone growth by deletion of Axinl in osteoblast precursor cells and analyzed bone growth in newborn and postnatal Axin1 O5X mice and found that hypertrophic cartilage area was largely expanded in AxinlOSX KO mice.A larger number of chondrocytes and unabsorbed cartilage matrix were found in the bone marrow cavity of Axin1OSX KO mice.Osteoclast formation in metaphyseal and subchondral bone areas was significantly decreased,demonstrated by decreased TRAPpositive cell numbers,associated with reduction of MMP9-and cathepsin K-positive cell numbers in Axin1 O5X KO mice.OPG expression and the ratio of O p g to Rankl were significantly increased in osteoblasts of Axinl O5X KO mice.Osteoclast formation in primary bone marrow derived microphage(BMM)cells was significantly decreased when BMM cells were cultured with conditioned media(CM)collected from osteoblasts derived from Axin1OSX mice compared with BMM cells cultured with CM derived from WT mice.Thus,the loss of Axinl in osteoblast precursor cells caused increased OPG and the decrease in osteoclast formation,leading to delayed bone growth in postnatal Axin1°sx KO mice.

Awareness intervention for Beijing neurologists regarding secondary prevention of cerebral infarction/transient ischemia Cross-sectional investigation

BACKGROUND： Stroke prevention guidelines should be made available application to aid in uniformity, timing, preciseness, and acceptance of disease. OBJECTIVE： To investigate the awareness of neurologists in some Beijing secondary prevention of cerebral infarction/transient ischemia. DESIGN： Cross-sectional study. to neurologists for clinical hospitals of intervention in SETTING： Beijing Tiantan Hospital, Beijing Anzhen Hospital, General Hospital of Beijing Military Area, Command of Chinese PLA, Beijing Chuiyangliu Hospital, Beijing 6^th Hospital, Beijing Hepingli Hospital, and Beijing Daxing District Hospital. PARTICIPANTS： A total of 28 （associate） chief physicians, 58 attending physicians, and 54 resident physicians who engaged in clinical treatment of cerebrovascular diseases were selected from 8 hospitals in Beijing from March to April 2007. All physicians provided informed consent. METHODS： Self-made closed questionnaires were provided for data collection, consisting of 16 questions that were single choice or multiple choice. Specifically, questions 1-7 focused on awareness of blood pressure regulation in different patients and first choice of decompression drug; questions 8-12 focused on awareness of lipid regulation; and questions 13-16 focused on awareness of anti-blood platelet drugs applied in secondary prevention. The scores ranged from 0-100 points, and each question was worth 6.25 points. The scores positively correlated with the awareness rate. To test leveling real-time, the survey lasted for a maximum of 20 minutes. One questionnaire was independently finished by each subject in the survey. MAIN OUTCOME MEASURES： Awareness intervention among neurologists during secondary prevention of cerebral infarction/transient ischemia and questionnaire scores. RESULTS： 140 subjects were included in the final analysis. ① The awareness rate among neurologists for intervention during secondary prevention of cerebral infarction/transient ischemia ranged from 0.7-57.9%, the scores ranged between 0-56 points, and the mean score was 26 points.② Scores of resident physicians were 0-56 points with a mean score of 26 points; attending physicians scored 6-50 points, with a mean score of 26 points; and chief physicians scored 6-50 points, with a mean score of 23 points. There were no significant differences among the various physicians （F = 0.771, t = 0.465, P 〉 0.05）. CONCLUSION： Awareness among neurologists of intervention during secondary prevention of cerebral infarction/transient ischemia is not ideal. However, there was no significant difference between professional titles.

Enhanced bioavailability of rebamipide nanocrystal tablets:Formulation and in vitro/in vivo evaluation

The purpose of this study was to formulate rebamipide nanocrystal tablets(REB-NTs)by wet-milling technique to enhance its dissolution rate and oral bioavailability.The formulation and preparation technology were screened by single factor tests with particle size and distribution as indicators.Rebamipide nanocrystals(REB-NSs)was then achieved by freeze-dry from the prepared nanosuspensions which were characterized by differential scanning calorimetry(DSC)and x-ray powder diffraction(XRD),while the vitro dissolution and the plasma drug concentration of the nanocrystal tablets were investigated.The results indicated that the prepared nanosuspensions got an average particle size of 286 nm,PI of 0.173 and the average Zeta potential of
18.2 mv.The average particle size of obtained REB-NSs’redispersibility was 278 nm,and the crystalline of REB-NSs was the same as the rebamipide bulk drug as shown by DSC and XRD.The drug dissolution rate of self-made nanocrystal tablets in different dissolutions was slightly faster than that from the reference tablets,REB-MTs(Mucosta®),while the Cmax and AUC0e24 of REB-NTs were 1 and 1.57 times higher than that of REB-MTs,which means the nanotechnology could significantly improve the oral bioavailability of rebamipide.

The studies of PLGA nanoparticles loading atorvastatin calcium for oral administration in vitro and in vivo

A biodegradable poly(lactic-co-glycolic acid) loading atorvastatin calcium(AC) nanoparticles(AC-PLGA-NPs) were prepared by probe ultrasonication and evaporation method aiming at improving the oral bioavailability of AC. The effects of experimental parameters, including stabilizer species, stabilizer concentration and pH of aqueous phase, on particle size were also evaluated. The resultant nanoparticles were in spherical shape with an average diameter of 174.7 nm and a narrow particle size distribution. And the drug loading and encapsulation efficiency were about 8% and 71%, respectively. The particle size and polydispersion were almost unchanged in 10 days. The release curves of AC-PLGA-NPs in vitro displaying sustained release characteristics indicated that its release mechanisms were matrix erosion and diffusion. The pharmacokinetic study in vivo revealed that the Cmax and AUC0-∞ of AC-PLGA-NPs in rats were nearly 3.7-fold and 4.7-fold higher than that of pure atorvastatin calcium suspension. Our results demonstrated that the delivery of AC-PLGANPs could be a promising approach for the oral delivery of AC for enhanced bioavailability.

Neuroprotective effect of high-dose hyperbaric oxygenation on rats with acute cerebral infarction in super-early stage:Curative comparison between 9-hour and 18-hour therapeutic protocols

BACKGROUND： Previously, only single short-time low-dose hyperbaric oxygenation （HBO） protocol was administrated to treat acute ischemic stroke in early stage and the conflicting results were obtained. There are few studies to report the outcome of administering long-time （can cover all the natural pathologic progression period） high-dose HBO to treat the disease. OBJECTIVE： To evaluate the therapeutic effect between two kinds of high-dose hyperbaric oxygenation on super-early stage of acute permanent middle cerebral artery occlusion （MCAO） in rats. DESIGN： A randomized controlled experimental study. SETTING： Beijing Tiantan Hospital, Capital Medical University; Beijing Research Institute of Neurosurgery. MATERIALS： Seventy-four male SD rats, aged 2.5 months old, weighing （ 280 ＋ 20） g, were provided by the Animal Institute, Chinese Academy of Medical Sciences. Hyperbaric oxygenation device was hyperbaric air cabin in which there was a self-made pure oxygen animal experimental cabin （made in China）. METHODS： This experiment was carried out in the municipal laboratory of Beijing Tiantan Hospital affiliated to Capital Medical University and Beijing Research Institute of Neurosurgery. ① Experimental intervention： All the rats were developed into models of permanent MCAO by suture embolism. Then, they were randomly divided into two HBO groups （9 hours and 18 hours） and control group, with 24 rats in each as well as 3-hour ultrastructure control group, with 2 rats. After being modeled for 3 hours, rats in the two HBO groups stayed in the hyperbaric cabin for 9 hours and 18 hours, separately. Rats in the 9-hour HBO group inhaled pure oxygen at hours 1, 3, 5, 7 and 9, and hyperbaric air at hours 2, 4, 6 and 8. Rats in the 18-hour HBO group inhaled pure oxygen at hours l, 3, 5, 7, 9, 11, 13, 15 and 17, and hyperbaric air at hours 2, 4, 6, 8, l0 12, 14, 16 and 18. After being created into models, rats in the control group and 3-hour ultrastructure control group breathed room air. ② Experimental evaluation： Neurologic functions of rat models in the 9-hour and 18-hour HBO groups as well as control group were scored by Bederson and Garica two neurological grading systems at hours 14 and 28 and on day 5; Infarct volume of rat models in the two HBO groups and control group was measured at hour 24 and on day 5 with NIH image processing software Image J; The pathological changes of brain tissue in the brain infarct region and its opposite region of rat models in the two HBO groups and 3-hour ultrastructure control group were observed with a Philips EM 208S transmission electron microscope. MAIN OUTCOME MEASURES： ① Neurobehavioral outcome. ② Rat brain infarct volume. ③ Ultrastructure of brain tissue in the ischemic penumbra of infarct models at the different time points RESULTS： ① Neurobehavioral outcome： After treatment, Garica score in the 9-hour and 18-hour HBO groups was significantly higher than that in the control group （P 〈 0.01）. Bederson score on day 5 after modeling in the 9-hour and 18-hour HBO groups was significantly lower than that in the control group （P 〈 0.01）. ② Cerebral infarct volume： Cerebral infarct volume in the 9-hour and 18-hour HBO groups was significantly smaller than that in the control group at hour 24 and on day 5 after modeling （P 〈 0.01）. In the 18-hour HBO group, infarct volume on day 5 after modeling was significantly larger than that at hour 24 after modeling （P 〈 0.05）. ③In the 3-hour ultrastructure control group, astrocyte edema and neuron damage around the capillary in the infarct cerebral tissue significantly relieved in the rats which were subjected to HBO. CONCLUSION： High dose of HBO is highly efficient in reducing infarct volume and improving neurobehavioral outcome of rats with acute cerebral infarction, and also has an important role in inhibiting the pathological progression of ischemic brain tissue after cerebral infarction.