Cerebral Infarction In Rats Research Articles

The effects of neuromuscular facilitation techniques on osteoporosis of hemiplegia limbs and serum leptin level in patients or rats with cerebral infarction

Primary objective: This study was to investigate the effect of proprioceptive neuromuscular facilitation techniques (NFT) on osteoporosis and serum leptin level in cerebral infarction patients or rats.Research design: Forty cerebral infarction rats were randomly grouped into control, sham operation, conventional treatment (CT) group and CT+NFT group. Fifty-two stroke patients with hemiplegia were included in this study.Methods and procedures: The bone mineral densities (BMD) of proximal hemiplegia limbs and serum ALP, BALP, BGP, IL-6 and leptin levels were detected using commercial kits.Main outcomes and results: In cerebral infarction rats, the BMD, BGP, BALP, ALP and leptin concentrations in the CT+NFT group was higher compared with the control and CT group, while serum IL-6 level was more reduced by CT+NFT than control and CT. In cerebral infarction patients, both CT and CT+NFT increased the BMD, ALP, BGP and leptin levels. In addition, compared with CT, the BMD, ALP, BGP and leptin levels were markedly increased by CT+NFT. CConclusion: NFC elevated the BMD of hemiplegia limbs, serum ALP, BGP, IL-6 and leptin levels and, thus, alleviated osteoporosis in rats and patients with cerebral infarction.

Abstract WP275: Hemorrhagic Transformation in Large Cerebral Infarction of Rats Pretreated With Dabigatran or Warfarin

Introduction: Dabigatran is effective in preventing stroke and reduces the risk of intracerebral hemorrhage when comparing with warfarin in patients with atrial fibrillation. However, it is uncertain whether hemorrhagic transformation (HT) after large cerebral infarction is also less frequent in dabigatran users than warfarin users. Hypothesis: We hypothesized that intracerebral HT would occur less frequently following large cerebral infarction in rats pretreated with dabigatran than those with warfarin. We also compared the change of matrix metalloproteinases (MMPs), which play a key role in HT. Methods: We performed randomized, double-blind experiments comparing warfarin and dabigatran in rats. After treatment with warfarin (0.2 mg/kg), dabigatran (20 mg/kg), or normal saline for 7 days, male wistar rats were subjected to permanent middle cerebral artery occlusion (MCAO) using a nylon thread. After 22 hours of MCAO, magnetic resonance imaging (MRI) was undergone (9.4T MR scanner, slice thickness = 0.5 mm). Operative procedures and assessment of MRI findings were performed by investigators who were blind to the group information. The presence of HT was assessed on gradient recalled-echo and infarction volume was measured on diffusion-weighted image. The MMP-2 and MMP-9 activities in brain tissues (obtained 24 hours after MCAO) were investigated using gelatin zymography. Results and Conclusions: Of the 33 rats with MRI, HT was observed less frequently in the dabigatran group than the warfarin group (placebo 14% [2/14], dabigatran 0% [0/10], and warfarin 100% [9/9], p < 0.001 [dabigatran vs warfarin]). The volume of infarction was similar between the groups (placebo 432.45 ± 78.35 mm3, dabigatran 432.42 ± 60.27 mm3, and warfarin 446.55 ± 73.55 mm3). MMP-2 and MMP-9 activities were not different between the groups. In the placebo, dabigatran, and warfarin groups, mean international normalized ratio were 1.38 ± 0.13, 1.73 ± 0.20, and 4.72 ± 2.92, respectively; mean activated partial thromboplastin times were 30.20 ± 7.49, 31.14 ± 7.02, and 55.06 ± 24.05, respectively. The risk of HT after large cerebral infarction was remarkably reduced in rats pretreated with dabigatran. MMPs did not seem to play a major role in reduced risk of HT.

Tocilizumab inhibits neuronal cell apoptosis and activates STAT3 in cerebral infarction rat model.

Cerebral infarction is a severe hypoxic ischemic necrosis with accelerated neuronal cell apoptosis in the brain. As a monoclonal antibody against interleukin 6, tocilizumab (TCZ) is widely used in immune diseases, whose function in cerebral infarction has not been studied. This study aims to reveal the role of TCZ in regulating neuronal cell apoptosis in cerebral infarction. The cerebral infarction rat model was constructed by middle cerebral artery occlusion and treated with TCZ. Cell apoptosis in hippocampus and cortex of the brain was examined with TUNEL method. Rat neuronal cells cultured in oxygen-glucose deprivation (OGD) conditions and treated with TCZ were used to compare cell viability and apoptosis. Apoptosis-related factors including B-cell lymphoma extra large (Bcl-xL) and Caspase 3, as well as the phosphorylated signal transducer and activator of transcription 3 (p-STAT3) in brain cortex were analyzed from the protein level. Results indicated that TCZ treatment could significantly prevent the promoted cell apoptosis caused by cerebral infarction or OGD (P < 0.05 or P < 0.01). In brain cortex of the rat model, TCZ up-regulated Bcl-xL and down-regulated Caspase 3, consistent with the inhibited cell apoptosis. It also promoted tyrosine 705 phosphorylation of STAT3, which might be the potential regulatory mechanism of TCZ in neuronal cells. This study provided evidence for the protective role of TCZ against neuronal cell apoptosis in cerebral infarction. Based on these fundamental data, TCZ is a promising option for treating cerebral infarction, but further investigations on related mechanisms are still necessary.

Effect of microRNA-155 on angiogenesis after cerebral infarction of rats through AT1R/VEGFR2 pathway.

To explore the function and mechanism of microRNA-155 to regulate the angiogenesis after the cerebral infarction of rats through the angiotensin II receptor 1 (AT1R)/vascular endothelial growth factor (VEGF) signaling pathway. Female SD rats were chosen for the construction of cerebral infarction model of rats using the modified right middle cerebral artery occlusion. The real-time PCR (RT-PCR) method was employed to detect the expression of microRNA-155 in each group at different time points after the cerebral infarction (1h, ld, 3d and 7d). SD rats were randomly divided into four groups (n=20 rats): sham operation group (Sham group), MACO group, MACO+microRNA-155 mimic group, and MACO+microRNA-155 inhibitor group. Sham group was given the free graft, while MACO+microRNA-155 mimic group and MACO+microRNA-155 inhibitor group were treated with microRNA-155 mimic and microRNA-155 inhibitor respectively. The Zea Longa 5-point scale was used to score the neurologic impairment of rats in each group; 2, 3, 5-triphenyl tetrazolium chloride staining to evaluate the volume of cerebral infarction of rats in each group; the immunohistochemistry to detect the expression of CD31; Western blot and RT-PCR to detect the expression of AT1R and VEGF receptor 2 (VEGFR2). The expression of microRNA-155 was increased in the cerebral ischemia tissue after the cerebral infarction. It was significantly increased at 1d of ischemia and maintained at the high level for a long time. Rats in the Sham group had no symptom of neurologic impairment, while rats in the MACO group had the obvious neurologic impairment. After being treated with microRNA-155 inhibitor, the neural function of MACO rats had been improved, with the decreased area of cerebral infarction. But after being treated with microRNA-155 mimic, the neural function was further worsened, with the increased area of cerebral infarction. Results of immunohistochemical assay indicated that microRNA-155 inhibitor could up-regulate the expression of CD31, while microRNA-155 mimic could down-regulate the expression of CD31. The RT-PCR found that, after being treated with microRNA-155 inhibitor, MACO rats had the increased expression of AT1R and VEGFR2 messenger RNA (mRNA); but after being treated with microRNA-155 mimic, the expression of AT1R and VEGFR2 mRNA was decreased. Results of Western blot showed that, after being treated with microRNA-155 inhibitor, MACO rats had the increased expression of AT1R and VEGFR2 mRNA; but after being treated with microRNA-155 mimic, the expression of AT1R and VEGFR2 mRNA was decreased. The inhibition of microRNA-155 can improve the neurologic impairment of rats with the cerebral infarction, reduce the volume of cerebral infarction and effectively promote the angiogenesis in the region of ischemia, which may be mediated through AT1R/VEGFR2 pathway.

Effects of Duloxetine on Urethral Continence Reflex and Bladder Activity in Rats with Cerebral Infarction

We investigated the effect of duloxetine, a norepinephrine and serotonin reuptake inhibitor, on the sneeze induced continence reflex and on bladder function in rats with cerebral infarction. Using urethane anesthesia the effect of duloxetine (1 mg/kg intravenously) on the amplitude of urethral responses during sneezing as well as urethral baseline pressure at the mid urethra was evaluated in normal female adult rats and cerebral infarction rats. Tilt leak point pressure was also measured. In normal and cerebral infarction rats continuous cystometry was evaluated before and after duloxetine injection. In cerebral infarction rats urethral baseline pressure was 43% lower than in normal rats but the amplitude of urethral responses during sneezing did not differ in the 2 groups. Duloxetine increased the amplitude of urethral responses during sneezing and urethral baseline pressure by 31% and 21%, respectively, in normal rats but did not affect either in cerebral infarction rats. Also, in cerebral infarction rats leak point pressure was 29% lower compared with normal rats. Duloxetine increased leak point pressure in normal rats but not in cerebral infarction rats. Cerebral infarction reduced intercontraction intervals without affecting the amplitude of bladder contractions compared with normal rats. Duloxetine prolonged intercontraction intervals in cerebral infarction rats but not in normal rats. These results suggest that cerebral infarction induces not only bladder overactivity but also stress urinary incontinence, which may account for mixed incontinence in patients with cerebral infarction. After cerebral infarction duloxetine reduced bladder overactivity but failed to enhance active urethral closure mechanisms during sneezing, suggesting that disorganization of the brain network after cerebral infarction might influence the effect of duloxetine on lower urinary tract function.

Effect of Inducible Co-Stimulatory Molecule siRNA in Cerebral Infarction Rat Models.

BackgroundT cell-induced inflammatory response and related cytokine secretion at the injury site may participate in the pathogenesis of cerebral infarction. Recent studies established inducible co-stimulatory molecule (ICOS) as a novel T cell-related factor for its activation and functions. We thus investigate the role of ICOS in cerebral infarction.Material/MethodsThe siRNA of ICOS was first used to suppress the gene expression in cultured lymphocytes. An in vivo study was then performed by intravenous application of ICOS siRNA in cerebral infarction rats. Survival rates, neurological scores, serum tumor necrosis factor (TNF)-α, interleukin (IL)-1, and IL-17 levels were observed.ResultsThe expression of ICOS in cultured lymphocytes was significantly suppressed by siRNA. In the in vivo study, the application of siRNA effectively lowered mortality rates of rats, in addition to the improvement of neurological behaviors and amelioration of cerebral tissue damage. Serum levels of TNF-α, IL-1 and IL-17 were all significantly suppressed after siRNA injection.ConclusionsICOS siRNA can protect brain tissues from ischemia injuries after cerebral infarction, improve limb movement and coordination, lower the mortality rate of rats, and inhibit T cell-induced cytokines. These results collectively suggest the potential treatment efficacy of ICOS siRNA against cerebral infarction.

The Effect of Umbilical Cord Blood Mesenchymal Stem Cells on the Neurological Function and the Expression of Caspase-3 in Cerebral Ischemiareperfusion Rats

Cerebral infarction, a type of ischemic stroke disease, is a threat to human health. Thrombolytic therapy and brain protection methods have been used to treat cerebral infarction clinically. Recently, cell therapy has become a hotspot. This study aimed to explore the effect of Umbilical Cord Blood Mesenchymal Stem Cells on the neurological function and the expression of caspase-3 in cerebral ischemia-reperfusion rats. Methods: The rat cerebral infarction models were established. The treatment group was injected into 2×106 Umbilical Cord Blood Mesenchymal Stem Cells; Sham-operated group and the control were injected into the same amount of cell culture media. Evaluation of neurological function was performed and the mRNA and protein expression level of caspase-3 was detected using RT-PCR and immunohistochemical method, respectively. Apoptosis analysis was assessed using a TUNEL kit. Results: Labeled Umbilical Cord Blood Mesenchymal Stem Cells survived well after being injected into rats, while the green fluorescence signal was not discovered in the control and sham-operated group; The neurological function of rats in the treatment group improved compared to the control (p 0.05). Immunohistochemistry results indicated that the number of caspase-3 positive cells decreased in the treatment group than the control (P 0.05). Apoptosis results showed that TUNEL-positive cells were significantly lower in the treatment group than the control group. This study indicated that Umbilical Cord Blood Mesenchymal Stem Cells contribute to the recovery of neurological function of cerebral ischemia-reperfusion rats and the expression of caspase-3 decreased.

The effect of transplanted bone marrow mononuclear cells under different transplant paths on neovascularization in ischemic cerebral infarction rats

Objective To investigate the effect of treatment with transplanted bone marrow mononuclear cells under different transplant paths on neovascularization in ischemic cerebral infarction rats. Methods The MCAO models were established by intraluminal vascular suture method. All the successful models were randomly divided into control group, intravenous transplantation group and subarachnoid transplantation group according to the random number table. The Extraction, isolation and culture of bone marrow mononuclear cells were extracted, isolated and cultured. The models in the control group were injected 200 μl PBS through the femoral vein. The models in the intravenous transplantation group were injected 200 μl containing 2×107 bone marrow mononuclear cells through the femoral vein. The models in the subarachnoid transplantation group were injected 200 μl containing 2×107 bone marrow mononuclear cells through the subarachnoid. The VEGF levels in cerebrospinal fluid of rats were detected using quantitative ELISA method. The vascular regenerations in the infarct area were observed by using quantitative immunofluorescence. Results After transplantation of bone marrow mononuclear cells 7 d, 14 d and 28 d, the VEGF levels of rat cerebrospinal fluid in subarachnoid transplantation group were (207.4±8.9)pg/ml, (171.2±10.3)pg/ml and (143.8±13.8)pg/ml, respectively, which were all higher than the VEGF levels in intravenous transplantation group, the differences were all statistically significant (P<0.05). After transplantation 14 d and 28 d, the BrdU-positive cells in subarachnoid transplantation group were (2043.8±514.2) and (1834.8±307.4), respectively, which were higher than the intravenous transplantation group, the differences were all statistically significant (P<0.05). The microvessel counts in subarachnoid transplantation group were (384.6±45.1) and (514.8±51.3), respectively, which were higher than that in the intravenous transplantation group, and the differences were all statistically significant (P<0.05). Conclusions Bone marrow mononuclear cells transplantation can increase VEGF secretion, and promote angiogenesis infarct. The effect of subarachnoid transplantation is better. Key words: Cerebral infarction; Bone marrow mononuclear cells; Transplantation; Angiogenesis

Reduction in Ischemic Cerebral Infarction is Mediated through Golgi Phosphoprotein 3 and Akt/mTOR Signaling Following Salvianolate Administration

Salvianolate has been reported to possess protective properties. However, its specific mechanisms have yet to be identified. Our study aimed to identify the molecular mechanism of antioxidative stress function of salvianolate on rat ischemia and reperfusion brain tissues. Rats were randomly distributed into three experimental groups: sham, model and intervention . All animal neurobehavioral tests were performed at the end of 72-h reperfusion per Longa's method, and rats with a score of 0 (no neurological deficit) or 4 (severe neurological deficit with impaired consciousness) were excluded. Brain slices were obtained after 72 h of reperfusion and stained with triphenyltetrazolium chloride. Western blot analysis and quantitative real-time polymerase chain reaction (qRT-PCR) were used to determine levels of GOLPH3, Akt/p-Akt, and mTOR/p-mTOR expressions in ischemic cortex. Salvianolate (18mg/kg intraperitoneal injection) significantly decreased the neurological deficit scores of rats in groups of 72 h I/R and reduced the number of TUNELpositive cells in the cerebral cortex when given at onset and at 24 and 48 h after reperfusion, leading to decreased cerebral infarction in rats after ischemia/reperfusion injury. Results of Western blot and qRT-PCR showed that salvianolate could significantly upregulate the expression of Golgi phosphoprotein-3 as well as the phosphorylation of Akt and mTOR. Above findings indicate that salvianolate exerts potent and long-term neuroprotective effects in the model of cerebral I/R, and Golgi phosphoprotein-3 and its downstream activation of Akt/mTOR signaling pathway may provide a new insight for the antioxidative effect of salvianolate.

Functional electrical stimulation-facilitated proliferation and regeneration of neural precursor cells in the brains of rats with cerebral infarction.

Previous studies have shown that proliferation of endogenous neural precursor cells cannot alone compensate for the damage to neurons and axons. From the perspective of neural plasticity, we observed the effects of functional electrical stimulation treatment on endogenous neural precursor cell proliferation and expression of basic fibroblast growth factor and epidermal growth factor in the rat brain on the infarct side. Functional electrical stimulation was performed in rat models of acute middle cerebral artery occlusion. Simultaneously, we set up a placebo stimulation group and a sham-operated group. Immunohistochemical staining showed that, at 7 and 14 days, compared with the placebo group, the numbers of nestin (a neural precursor cell marker)-positive cells in the subgranular zone and subventricular zone were increased in the functional electrical stimulation treatment group. Western blot assays and reverse-transcription PCR showed that total protein levels and gene expression of epidermal growth factor and basic fibroblast growth factor were also upregulated on the infarct side. Prehensile traction test results showed that, at 14 days, prehension function of rats in the functional electrical stimulation group was significantly better than in the placebo group. These results suggest that functional electrical stimulation can promote endogenous neural precursor cell proliferation in the brains of acute cerebral infarction rats, enhance expression of basic fibroblast growth factor and epidermal growth factor, and improve the motor function of rats.

Cluster analysis for acupoint specificity of acupuncture effect based on cerebral infarction rat model

To study the acupoint specificity through the comprehensive evaluation of the acupuncture effect on rat model with the middle cerebral artery occlusion (MCAO). Duplicated MCAO model by Zea-longa's thread ligation was assessed by Zausinger's six-point method, and rats with 1-3 scores were chosen to be grouped. According to the randomized and controlled principle, rats were divided into 6 basic control groups (including normal group, sham group, model control group, model group without intervention, Nimodipine group, lateral-to-Renzhong group) and 6 acupuncture groups [including Neiguan (PC6) group, Weizhong (BL40) group, Chize (LU5) group, Sanyinjiao (SP6) group, Renzhong (DU6) group and non-acupoint group]; in each acupoint or non-acupoint 9 different parameter combinations were respectively set by orthogonal intersection method. There were in total 60 groups, and each group had 12 rats. The rats were treated by acupuncture with the lifting-thrusting manipulation every 12 h, in total 6 times. Indices of neurobehavioral scores, cerebral blood flow, infarction rate, microcirculation, and light microscope, etc. were measured. In order to comprehensively evaluate the acupuncture effect to research the specificity of acupoint, a cluster analysis was made with SPSS17.0 for the comprehensive effect scores of the samples computed according to the comprehensive evaluation models, and then sorting and classification were made for the comprehensive effect scores. In the acupuncture groups every acupoint had different therapeutic effect due to different acupuncture parameter combinations; among the acupuncture groups the orders of curative effect were as followings: Neiguan group was of exceptional result, Weizhong group and Sanyinjiao group were of valid results in upper level, Chize group and Renzhong group were of valid results in lower level, and non-acupoint group was of invalid result; the therapeutic result of acupoint group was superior to non-acupoint group; and the curative effect of acupuncture group was also superior to basic control group. The acupoint has the specificity of acupuncture effect, and the acupoint specificity is relative.

Studies on cerebroprotective potential of 2,4,6-trisubstituted-1,3,5-pyrimidines in global ischemia/reperfusion induced cerebral infarction in rats

Cerebral I/R injury is mainly characterized by oxidant production, complement activation, leukocyte–endothelial cell adhesion, platelet–leukocyte aggregation, increased microvascular permeability and decreased endothelium-dependent relaxation. I/R injury can lead to multiorgan dysfunction or death. In recent years, pyrimidines have received much attention of researchers because of their vasodilator, anti-inflammatory and antioxidant properties. Studies on cerebroprotective mechanism of pyrimidine derivatives on cerebral I/R injury are limited. Hence it is worthwhile to study the role of pyrimidines as cerebroprotective agents and evaluated for their possible inherent underlying mechanisms. Experimental cerebral infarction was produced by bilateral common carotid artery occlusion (global cerebral ischemia) for 30 min followed by 4 h reperfusion in Wistar rats. The oxidative and anti-inflammatory biomarkers were estimated and percentage infarction was determined. A dose dependent cerebroprotective action of pyrimidines (AUCP1 and AUCP2) in terms of limiting the infarct size was observed in the present in vivo model of cerebral I/R in Wistar rats. The antioxidant role of pyrimidines (AUCP1 and AUCP2) in cerebroprotection was confirmed by measuring SOD, CAT, MDA, levels. MDA levels were decreased; SOD and CAT levels were increased by treatment with pyrimidines (AUCP1 and AUCP2). The cerebroprotective actions of pyrimidines (AUCP1 and AUCP2) are partially attributed to their anti-inflammatory effects against I/R injury in rats as evidenced by significant reduction in pro-inflammatory markers MPO, TNF-α and significant increase in anti-inflammatory marker IL-10. Pyrimidines (AUCP1 and AUCP2) evaluated in the present investigation has offered significant cerebroprotection against ischemia-reperfusion induced cerebral infarction in rats.

The roles of MMP-9/TIMP-1 in cerebral edema following experimental acute cerebral infarction in rats

Matrix metalloproteinases 9 (MMP-9) and its endogenous inhibitor, tissue inhibitor of metalloproteinases 1 (TIMP-1), regulate homeostasis and turnover of the extra cellular matrix (ECM). They play important roles in acute cerebral infarction (ACI). The contributions of MMP-9 and TIMP-1 to the early stages of ACI are not completely understood. This study investigates the time course of MMP-9 and TIMP-1 and their relations to edema after ACI in rats. Serum concentrations of MMP-9 and TIMP-1 protein were measured using ELISA and mRNA level were measured using real-time PCR. Brain samples were harvested and the brain water content (BWC) was measured. Results revealed that MMP-9 concentration increased fast during the first 12h after ACI, while after 12h the increase was much slower. The MMP-9 protein concentration was elevated earlier than the mRNA level. BWC increased starting at 6h after ACI to reach a peak at 12h and decreased back to normal levels at 72h. Both the MMP-9 protein and its mRNA were positively correlated with BWC, however no correlation was found between TIMP-1 levels and BWC. The MMP-9/TIMP-1 protein ratio was more closely correlated with BWC than the MMP-9 concentration. These results indicate that brain edema induced by ACI is associated with increased MMP-9 levels and MMP-9/TIMP-1 ratio in serum.

Exercise Therapy Augments the Ischemia-Induced Proangiogenic State and Results in Sustained Improvement after Stroke

The induction of angiogenesis will stimulate endogenous recovery mechanisms, which are involved in the long-term repair and restoration process of the brain after an ischemic event. Here, we tested whether exercise influences the pro-angiogenic factors and outcomes after cerebral infarction in rats. Wistar rats were exposed to two hours of middle-cerebral artery occlusion and reperfusion. Different durations of treadmill training were performed on the rats. The expression of matrix metalloproteinase 2 (MMP2) and vascular endothelial growth factor (VEGF)-related genes and proteins were higher over time post-ischemia, and exercise enhanced their expression. Sixteen days post-ischemia, the regional cerebral blood flow in the ischemic striatum was significantly increased in the running group over the sedentary. Although no difference was seen in infarct size between the running and sedentary groups, running evidently improved the neurobehavioral score. The effects of running on MMP2 expression, regional cerebral blood flow and outcome were abolished when animals were treated with bevacizumab (BEV), a VEGF-targeting antibody. Exercise therapy improves long-term stroke outcome by MMP2-VEGF-dependent mechanisms related to improved cerebral blood flow.

Comparative study among three different methods of bone marrow mesenchymal stem cell transplantation following cerebral infarction in rats

The objective of this study was to investigate the effects of transplanted bone marrow mesenchymal stem cells (BMSCs) administered via internal jugular vein injection, carotid artery injection, or intraventricular transplantation for the treatment of cerebral infarction, which was modeled in rats. The neurological scores of the treated rats and the distribution of the transplanted cells (GFP-labeled) in the infarction area were evaluated. The cerebral infarction model was produced by inserting a modified Zea-longa suture, which generated middle cerebral artery occlusion (MCAO). The GFP-labeled BMSCs were transplanted through the jugular vein or the carotid artery or by stereotactic intraventricular delivery to the infarction models 1 week after the cerebral infarction was established. The ‘Nerve Function Score’ of the model rats was recorded before and after BMSC transplantation. Brain tissue sections were examined under a fluorescence microscope. We determined that the transplanted BMSCs rescued brain function, which was indicated by a decrease in the neurological scores (P<0·05) following BMSC transplantation. The effect of BMSC transplantation was reflected in decreases in the neurological score in the intraventricular transplantation group, the carotid artery transplantation group, and the jugular vein graft group*. The transplanted BMSCs were able to migrate to the brain injury area and the cortex and survived the infarction; thus, BMSCs may promote the recovery of nerve function.

Preventive and Therapeutic Effects of Ginsenoside Rb1 for Neural Injury During Cerebral Infarction in Rats

To examine the preventive and therapeutic effects of ginsenoside Rb1 for neural injury during cerebral infarction, we used a middle cerebral artery occlusion (MCAO) model in rats to investigate the effects of ginsenoside Rb1 with Edaravone as a control. Ginsenoside Rb1 was given to the rats by intragastric administration either before or after the MCAO surgery to study its preventive and therapeutic effects. Ginsenoside Rb1-treated rats had a smaller infarct volume than the positive control. Interleukin-1 (IL-1), brain-derived neurotrophic factor (BDNF), tumor necrosis factor-α (TNF-α), neurofilament (NF) and growth associated protein-43 (GAP-43) were measured to determine brain damage and the recovery of nerves. These findings suggest that ginsenoside Rb1 has neuroprotective effects in rats, and the protection efficiency is higher than Edaravone. The protective mechanism is different from Edaravone. The preventive ability of ginsenoside Rb1 is higher than its repair ability in neuroprotection in vivo.

Bilateral cortical hyperactivity detected by fMRI associates with improved motor function following intravenous infusion of mesenchymal stem cells in a rat stroke model

Intravenous transplantation of mesenchymal stem cells (MSCs) derived from bone marrow ameliorates functional deficits in rat cerebral infarction models. In this study, MSCs were intravenously administered 6h after right middle cerebral artery occlusion (MCAO) induction in rat. Functional MRI (fMRI) during electrical stimulation of the left forepaw and behavioral testing (treadmill stress test) were carried out at day 1, 4, 7, 14, 21, 28 and 42 following MCAO. In medium infused group (n=20) electrical stimulation of the left forepaw elicited a unilateral (right cortex) activated signal detected by fMRI in the infarcted somatosensory cortex. In the MSC infused animals two fMRI patterns were observed: unilateral (n=17) and bilateral (n=19) activation of sensorimotor cortex. In the MSC group both unilateral and bilateral cortical activated animals displayed significantly improved motor function compared to the medium infused group. However, the bilateral activated pattern in the MSC group showed the greatest functional recovery. Lesion volume as calculated from high intensity signals using T2WI was less in the MSC groups as compared to the medium group, but the lesion volume for the unilateral and bilateral signals in the MSC group was the same. These results suggest that the presence of a bilateral signal in sensorimotor cortex as detected by fMRI was more predictive of improved functional outcome than lesion volume alone.

Neuroprotective effects of focal brain cooling on photochemically-induced cerebral infarction in rats: Analysis from a neurophysiological perspective

Although systemic hypothermia provides favorable outcomes in stroke patients, it has only been adopted in a limited number of patients because of fatal complications. To resolve these issues, focal brain cooling (FBC) has recently drawn attention as a less-invasive treatment for brain injuries. Therefore, we investigated whether FBC has a favorable effect on focal cerebral ischemia (FCI). Male-adult-Wistar rats were used. Under general anesthesia, a small burr hole was made and FCI was induced in the primary sensorimotor area (SI-MI) using photothrombosis. An additional craniotomy was made over the SI-MI and FBC was performed at a temperature of 15°C for 5h. Electrocorticograms (ECoG) were recorded on the border cortex of the ischemic focus. Thereafter, rats were sacrificed and the infarct area was measured. In another experiment, rats were allowed to recover for 5 days after cooling and neurobehavioral function was evaluated. FBC suppressed all ECoG frequency bands during and after cooling (p<0.05), except for the delta frequency band in the precooling versus rewarming periods. The injured areas in the cooling and non-cooling groups were 0.99±0.30 and 1.71±0.54mm2, respectively (p<0.03). The grip strength at 2 days after surgery was preserved in the cooling group (p<0.05). We report the novel finding that epileptiform discharges were suppressed in the ischemic border, the infarct area was reduced and neurobehaviour was preserved by FBC. These results indicate that FBC is neuroprotective in the ischemic brain and has demonstrated therapeutic potential for cerebral infarction.

Low-speed treadmill running exercise improves memory function after transient middle cerebral artery occlusion in rats

Physical exercise may enhance the recovery of impaired memory function in stroke rats. However the appropriate conditions of exercise and the mechanisms underlying these beneficial effects are not yet known. Therefore, the purpose of this study was to investigate the effect exercise intensity on memory function after cerebral infarction in rats. The animals were subjected to middle cerebral artery occlusion (MCAO) for 90min to induce stroke and were randomly assigned to four groups; Low-Ex, High-Ex, Non-Ex and Sham. On the fourth day after surgery, rats in the Low-Ex and High-Ex groups were forced to exercise using a treadmill for 30min every day for four weeks. Memory functions were examined during the last 5 days of the experiment (27–32 days after MCAO) by three types of tests: an object recognition test, an object location test and a passive avoidance test. After the final memory test, the infarct volume, number of neurons and microtubule-associated protein 2 (MAP2) immunoreactivity in the hippocampus were analyzed by histochemistry. Memory functions in the Low-Ex group were improved in all tests. In the High-Ex group, only the passive avoidance test improved, but not the object recognition or object location tests. Both the Low-Ex and High-Ex groups had reduced infarct volumes. Although the number of neurons in the hippocampal dentate gyrus of the Low-Ex and High-Ex groups was increased, the number for the Low-Ex group increased more than that for the High-Ex group. Moreover hippocampal MAP2 immunoreactivity in the High-Ex group was reduced compared to that in the Low-Ex group. These data suggest that the effects of exercise on memory impairment after cerebral infarction depend on exercise intensity.

In vitro and in vivo pharmacological profile of the selective β3-adrenoceptor agonist mirabegron in rats

To investigate the pharmacological properties of mirabegron in in vitro and in vivo, the effects on cAMP accumulation in Chinese hamster ovary (CHO) cells expressing rat β-adrenoceptors, the relaxant activity in isolated rat bladder smooth muscle, and the voiding effects in cerebral infarcted rats were evaluated. Mirabegron increased cAMP accumulation with EC(50) value and intrinsic activity of 19nmol/L and 1.0, respectively, in CHO cells expressing rat β(3)-adrenoceptors. The EC(50) values and the intrinsic activities of mirabegron were 610nmol/L and 0.6 for rat β(1)-adrenoceptors and were sumless and 0.1 for β(2)-adrenoceptors, respectively. Mirabegron showed concentration-dependent relaxant and full agonistic effects in rat bladder strips under passive tension with EC(50) value of 290nmol/L. The concentration-response curve of mirabegron was affected neither by the β(1)-adrenoceptor selective antagonist CGP-20712A nor by the β(2)-adrenoceptor selective antagonist ICI-118,551. In in vivo studies with cerebral infarcted rats, a significant decrease in the volume voided per micturition compared with sham-operated rats was observed. Mirabegron dose-dependently increased the volume voided per micturition. In conclusion, we have extended the selectivity profile of mirabegron to rats and demonstrated that it is effective via stimulation of β(3)-adrenoceptors in a rat cerebral infarction model of detrusor overactivity.