Kenmei Mizutani

Alteration of protein expression profile following voluntary exercise in the perilesional cortex of rats with focal cerebral infarction

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.

Analysis of protein expression profile in the cerebellum of cerebral infarction rats after treadmill training.

Mizutani K, Sonoda S, Hayashi N, Takasaki A, Beppu H, Saitoh E, Shimpo K: Analysis of protein expression profile in the cerebellum of cerebral infarction rats after treadmill training. Objective:To investigate the relation between protein expression changes in the cerebellum and improvement of motor coordination in rats with cerebral infarction. Design:The rat group with treadmill training (n = 10) were compared with the rat group without treadmill training (n = 10) after 2.5 hrs of transient middle cerebral artery occlusion. Motor performance measured by the rotarod test and alteration of protein expression using two-dimensional electrophoresis based on proteomics in the cerebellum were examined. Results:In behavioral evaluation, the mean latency until falling from the rotating rod in the group with treadmill training was significantly longer (P < 0.01) than that in the group without treadmill training 24 days after surgery. As for protein expression, it was revealed by proteome analysis and Western blotting that the expression of the two protein spots, 25-kDa synaptosomal-associated protein and glial fibrillary acidic protein, were significantly enhanced in the cerebellum of rats with treadmill training than that in rats without a treadmill training. Conclusions:The 25-kDa synaptosomal-associated protein and glial fibrillary acidic protein may be related to the underlying mechanisms of improvement of motor coordination and exercise-induced angiogenesis, that is, remodeling of synaptic connections and proliferation of astroglial cells, respectively.

Immunohistochemical localization of mitochondrial fatty acid β-oxidation enzymes in Müller cells of the retina

The presence of a mitochondrial fatty acid β-oxidation system in the retina was shown by immunohistochemistry. Fatty acids are considered to serve as a major energy source metabolized by fatty acid β-oxidation together with glucose metabolized by glycolysis in the organs of the entire body, but almost nothing is known about this metabolic system in the retina. Adult rat retinae were subjected to immunofluorescence and immuno-electron microscopy for the localization of fatty acid β-oxidation enzymes, together with western blot analysis for quantitation of the amount of enzyme proteins and DNA microarray analysis for gene expression. All the enzymes examined were shown to be present in the retina, but in small amounts, with the amount of protein and gene expression in the retina being about 1/10 of those in the liver. Immunohistochemistry at light and electron microscopic levels revealed the enzymes to be more preferentially localized to the mitochondria of Müller cells than the retinal neurons. The Müller cells were isolated from the retina and confirmed for the presence of mitochondrial fatty acid β-oxidation enzymes. A mitochondrial fatty acid β-oxidation system was thus shown to be present in the retina heterogeneously.

Immunohistochemical Localization of Mitochondrial Fatty Acid β-Oxidation Enzymes in Rat Testis

The testis consists of two types of tissues, the interstitial tissue and the seminiferous tubule, which have different functions and are assumed to have different nutritional metabolism. The localization of enzymes of the mitochondrial fatty acid β-oxidation system in the testis was investigated to obtain a better understanding of nutrient metabolism in the testis. Adult rat testis tissues were subjected to immunoblot analysis for quantitation of the amounts of enzyme proteins, to DNA microarray analysis for gene expression, and to immunofluorescence and immunoelectron microscopy for localization. Quantitative analysis by immunoblot and DNA microarray revealed that enzymes occur abundantly in Leydig cells in the interstitial tissue but much less so in the seminiferous tubules. Immunohistochemistry revealed that Leydig cells in the interstitial tissue and Sertoli cells in the seminiferous tubules contain a full set of mitochondrial fatty acid β-oxidation enzymes in relatively plentiful amounts among the cells in the testis, but that this is not so in spermatogenic cells. This characteristic localization of the mitochondrial fatty acid β-oxidation system in the testis needs further elucidation in terms of a possible role for it in the nutritional metabolism of spermatogenesis.

Pelvic axis-based gait analysis for ataxic mice

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, Parkinsons disease model (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine treated (MPTP)), and cerebellum hypoplasia (cytosine-β-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-wob/t 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.

Ritanserin, a serotonin-2 receptor antagonist, inhibits functional recovery after cerebral infarction

It has been suggested that serotonin (5-HT) may be implicated in functional recovery after stroke; however, the underlying molecular mechanisms remain unknown. Here, the role of 5-HT was verified using ritanserin, a potent 5-HT2A receptor antagonist, and protein expression and modification were analyzed to further understand the association between paralysis recovery and molecular mechanisms in the brain. Experimental cerebral cortex infarctions were induced by photothrombosis in rats. Voluntary exercise was initiated 2 days after surgery. Motor performance was then measured using the rotarod test. Differences in protein expression and phosphorylation in the perilesional cortex were analyzed using western blot. In behavioral evaluations, performance in the rotarod test was significantly increased by exercise. However, there was a significantly lower value in time until falling after combined exercise and ritanserin administration compared with that of exercise alone. Protein expression analysis revealed that phosphorylation of protein kinase C (PKC) &agr;, PKC&egr;, and growth-associated protein 43 (GAP43) was significantly upregulated by exercise. These effects were attenuated by ritanserin administration. These data suggest that 5-HT may be related to the underlying mechanisms of exercise-dependent paralysis recovery, that is, exercise-dependent plasticity through the phosphorylation of PKC and GAP43.