水谷 謙明

Although it has been suggested that the combination of exercise and bryostatin-1 administration may induce greater functional recovery than exercise alone, the detailed molecular mechanisms are not well known. Here, we examined the relationship between this combination treatment and monoamine dynamics in the cerebral cortex peri-infarction area to promote our understanding of these molecular mechanisms. Experimental cerebral cortex infarctions were produced by photothrombosis in rats. Voluntary exercise was initiated 2 days after surgery. Motor performance was then measured using the rotarod test. Monoamine concentrations in the perilesional cortex were analyzed by high-performance liquid chromatography. In behavioral evaluations, performance in the rotarod test was significantly increased by exercise. Moreover, performance in the rotarod test after the combination of exercise and bryostatin-1 administration was significantly greater than that after exercise alone. In the analysis of monoamines, serotonin (5-HT) concentrations were significantly higher in the groups treated with exercise and bryostatin-1. In addition, 5-HT turnover was significantly lower in the groups treated with exercise and bryostatin-1. Furthermore, the mean latency in the rotarod test showed a significant positive correlation with 5-HT levels. In immunohistochemical analysis, 5-HT immunoreactivity in the dorsal raphe nucleus was shown to be higher in the groups treated with exercise. In the present study, we detected changes in the levels of monoamines associated with the combined treatment of exercise and bryostatin-1 administration in the perilesional cortex. It has been suggested that this combination of therapies may affect 5-HT turnover and serve to increase local 5-HT concentrations in the perilesional area. Copyright (C) 2016 Wolters Kluwer Health, Inc. All rights reserved.

Background and objective: Malocclusion induced by raising the bite causes chronic stress. Chronic stress leads to increased plasma corticosterone levels and impaired hippocampal function due to impaired neurogenesis or increased apoptosis in the hippocampus. The present study aimed to clarify the mechanisms underlying the impaired hippocampal function induced by the bite-raised condition in aged senescence-accelerated mouse prone 8 (SAMP8). Design: Nine-month-old aged SAMP8 mice were randomly divided into control and bite-raised groups. The vertical dimension of the bite was raised by applying resin to the molars. We evaluated newborn cell proliferation, survival, differentiation, and apoptosis in the hippocampal dentate gyrus (DG). Hippocampal brain-derived neurotrophic factor (BDNF) levels were also measured. Results: The bite-raised mice exhibited a significant decrease in proliferation, survival, and differentiation of newborn cells into neurons in the hippocampal DG compared with controls. The number of apoptotic cells in the hippocampal DG was increased at 7 and 14 days after the bite-raising procedure. Expression of BDNF protein and mRNA in the hippocampus was also decreased in the bite-raised mice. Conclusion: Bite-raised aged SAMP8 mice exhibited decreased neurogenesis, increased apoptosis in the hippocampal DG, and decreased hippocampal BDNF expression, in association with hippocampus-dependent learning and memory deficits. (C) 2016 Elsevier Ltd. All rights reserved.

Background and objective: Teeth are crucial, not only for mastication, but for overall nutrition and general health, including cognitive function. Aged mice with chronic stress due to tooth loss exhibit impaired hippocampus-dependent learning and memory. Exposure to an enriched environment restores the reduced hippocampal function. Here, we explored the effects of an enriched environment on learning deficits and hippocampal morphologic changes in aged senescence-accelerated mouse strain P8 (SAMP8) mice with tooth loss. Design: Eight-month-old male aged SAMP8 mice with molar intact or with molars removed were housed in either a standard environment or enriched environment for 3 weeks. The Morris water maze was performed for spatial memory test. The newborn cell proliferation, survival, and differentiation in the hippocampus were analyzed using 5-Bromodeoxyuridine (BrdU) immunohistochemical method. The hippocampal brain-derived neurotrophic factor (BDNF) levels were also measured. Results: Mice with upper molars removed (molarless) exhibited a significant decline in the proliferation and survival of newborn cells in the dentate gyrus (DG) as well as in hippocampal BDNF levels. In addition, neuronal differentiation of newly generated cells was suppressed and hippocampus-dependent spatial memory was impaired. Exposure of molarless mice to an enriched environment attenuated the reductions in the hippocampal BDNF levels and neuronal differentiation, and partially improved the proliferation and survival of newborn cells, as well as the spatial memory ability. Conclusion: These findings indicated that an enriched environment could ameliorate the hippocampus-dependent spatial memory impairment induced by molar tooth loss. (C) 2015 Elsevier Ltd. All rights reserved.

Recently, it has become widely known that neuronal reorganization in the perilesional cortex contributes to some improvement of hemiparesis after stroke. Here, the authors examined in vivo the effects of administration of bryostatin-1, an activator of protein kinase C, combined with voluntary exercise on functional recovery and on cortical phosphorylation of -amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor subunit GluR1 after infarction. In behavioral evaluation, the mean latency until falling from a rotating rod in the group with exercise and administered agent at 8 days after infarction was significantly longer than that in the other groups. Although there were no significant changes in GluR1 phosphorylation between bryostatin-1 administration alone and the untreated groups, exercise induced an increase in phosphorylated-Ser845-GluR1. Moreover, combining exercise with administration led to increased phosphorylated-Ser831-GluR1. These results suggest that bryostatin-1 facilitated exercise-induced paralysis recovery, which is possibly mediated by synaptic plasticity related to an increase in synaptic transmission efficiency.

Predicting recovery from hemiparesis after stroke is important for rehabilitation. A few recent studies reported that the levels of some growth factors shortly after stroke were positively correlated with the clinical outcomes during the chronic phase. The aim of this study was to examine the relationships between the serum levels of growth factors (vascular endothelial growth factor [VEGF], insulin-like growth factor-I [IGF-I], and hepatocyte growth factor [HGF]) and improvement in hemiparesis in stroke patients who received rehabilitation in a postacute rehabilitation hospital. Subjects were 32 stroke patients (cerebral infarction: 21 and intracerebral hemorrhage [ICH]: 11). We measured serum levels of VEGF, IGF-I, and HGF and 5 items of the Stroke Impairment Assessment Set (SIAS) for hemiparesis on admission and at discharge. Age-matched healthy subjects (n 5 15) served as controls. Serum levels of VEGF and HGF in cerebral infarct patients on admission were higher than those in control subjects, and the serum levels of IGF-I in stroke patients were lower than those in controls. The level of HGF in ICH patients on admission was negatively correlated with gains in SIAS, and higher outliers in HGF concentration were correlated with lower gains in SIAS. Focusing on the extremely high levels of these factors may be a predictor of the low recovery from hemiparesis after stroke.

Recently, it has become widely known that rehabilitative training after stroke brings about some improvement of paralysis and disability; however, not much is known about the relationship between paralysis recovery and the participation of plasticity-related molecules. Hence, the localization and level of expression of several proteins in the cerebral cortex of rat groups with/without voluntary exercise using a running wheel after photo thrombotic infarction were examined in this study. In behavioral evaluation, the mean latency until falling from a rotating rod in the group with voluntary exercise at 6 days after infarction was significantly longer than that in the group without exercise. Immunohistochemical localization of c-Fos protein after behavioral test occurred in the area surrounding the infarction core in the exercise group. In protein expression analysis, protein kinase C (PKC), growth-associated protein 43 (GAP43) and phosphorylated at serine 41 GAP43 (p-GAP43) were significantly increased after voluntary exercise compared with those in rats without exercise. Expression of PKC immunoreactivity was observed in layer III of the perilesional cortex in rats with exercise, and the intracellular localization in the pyramidal neurons was mainly translocated to the plasma membrane. The expression and localization of these proteins may be related to the underlying mechanisms of exercise-induced paralysis recovery, that is, neuronal plasticity and remodeling of cortical connections through the phosphorylation of GAP43 by interaction with PKC. In the present study, the participation of at least some of the modulators associated with the improvement of motor deficit adjacent to the brain lesion might have been detected.

Background: Although different gait analysis methods such as Walking Track Analysis exist, they cannot be used to demonstrate the physical condition of mice with specific gait disorder characteristic. Therefore, we developed a new method for the gait analysis of such mice to accurately assess hind limb angle based on the pelvic axis. New method: We established and verified a gait analysis method capable of pelvic axis-based limb angle measurement by video-recording the gait of a control mice group (C57BL/6J(B6)) and three ataxic mice (ataxic B6-wob/t, Parkinson's disease model (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine treated (MPTP)), and cerebellum hypoplasia (cytosine-beta-D-arabinofuranoside treated)) from the ventral side. Results: The assessed hind limb angles of B6-wob/t and MPTP-treated mice were significantly wider than B6 mice (p<0.01). Moreover, we could draw separating lines with slopes of minus one that could separate the data of each group in-the scatter plot of the normalized hind limb step width and angle. Comparison with existing methods: We found no significance when we applied the already existing nose-tail method for the analysis of the hind limb angles of B6 and B6-woblt mice. In the nose-tail method, since the whole body axis of the trunk varies while the trunk of the mouse is laterally bent changing the hind limb angle, B6 and B6-wob/t mice could not be differentiated. However, the two mice groups could be differentiated by the pelvic axis-based gait analysis method. Conclusion: The pelvic axis-based gait analysis method is promising and valid for mice with gait disorder. (C) 2013 Elsevier B.V. All rights reserved.

Identification of functional molecules in the brain related to improvement of motor dysfunction after stroke will contribute to establish a new treatment strategy for stroke rehabilitation. Hence, monoamine changes in basal ganglion related to motor control were examined in groups with/without voluntary exercise after cerebral infarction. Cerebral infarction was produced by photothrombosis in rats. Voluntary exercise using a running wheel was initiated from 2 days after surgery. Motor performance was measured by the accelerated rotarod test. Monoamine concentrations in striatum were analyzed using HPLC and immunohistochemical staining performed with anti-tyrosine hydroxylase antibody. In behavioral evaluation, the mean latency until falling from the rotating rod in the group with exercise (infarction-EX group) was significantly longer than that in the group without exercise (infarction-CNT group). When concerning the alteration of monoamine concentration between before and 2 days after infarction, dopamine level showed a significant increase 2 days after infarction. Subsequently, dopamine level was significantly decreased in the infarction-EX group at 10 days after infarction; in contrast, both norepinephrine and 5-HT concentrations were significantly higher in the infarction-EX group than in the infarction-CNT group. Furthermore, duration of rotarod test showed a significant inverse correlation with dopamine levels and a significant positive correlation with 5-HT levels. In immunohistochemical analysis, tyrosine hydroxylase immunoreactivity in substantia nigra pars compacta was shown to increase in the infarction-CNT group. In the present study, at least some of the alterations of monoamines associated with the improvement of paralysis in the basal ganglion related to motor control might have been detected.

Identification of functional molecules in the brain related to improvement of the degree of paralysis or increase of activities will contribute to establishing a new treatment strategy for stroke rehabilitation. Hence, protein expression changes in the cerebral cortex of rat groups with/without voluntary exercise using a running wheel after cerebral infarction were examined in this study. Motor performance measured by the accelerated rotarod test and alteration of protein expression using antibody microarray analysis comprised 725 different antibodies in the cerebral cortex adjacent to infarction area were examined. In behavioral evaluation, the mean latency until falling from the rotating rod in the group with voluntary exercise for five days was significantly longer than that in the group without voluntary exercise. In protein expression profile, fifteen proteins showed significant quantitative changes after voluntary exercise for five days compared to rats without exercise. Up-regulated proteins were involved in protein phosphorylation, stress response, cell structure and motility, DNA replication and neurogenesis (11 proteins). In contrast, down-regulated proteins were related to apoptosis, cell adhesion and proteolysis (4 proteins). Additional protein expression analysis showed that both growth-associated protein 43 (GAP43) and phosphorylated serine41 GAP43 (pSer41-GAP43) were significantly increased. These protein expression changes may be related to the underlying mechanisms of exercise-induced paralysis recovery, that is, neurite formation, and remodeling of synaptic connections may be through the interaction of NGF, calmodulin, PKC and GAP43. In the present study at least some of the participation of modulators associated with the improvement of paralysis might be detected. (C) 2011 Elsevier B.V. All rights reserved.