Keigo Tamakoshi

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 90 min 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 30 min 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.

Treadmill running improves motor function and alters dendritic morphology in the striatum after collagenase-induced intracerebral hemorrhage in rats

It is well known that early rehabilitation is effective for functional recovery after intracerebral hemorrhage (ICH); however, the mechanisms have not been well described. The purpose of this study was to elucidate the effects of early rehabilitative therapy (treadmill running) on recovery of motor function and alteration of brain histology after ICH. Male Wistar rats, under deep anesthesia, were placed in a stereotaxic apparatus and injected with collagenase into the left striatum to induce ICH. Sham operated animals were treated with saline. All animals were randomly assigned to treadmill exercise (for 30 min/day, 9 m/min, between 4 and 14 days after surgery) and control and were designated to one of four groups: sham+control (SC), sham+treadmill (ST), ICH+control (IC), ICH+treadmill (IT). Motor deficit score (MDS) was assessed daily after surgery. Volume of tissue lost, dendritic morphology and PSD-95 protein level in the striatum were analyzed at 15 days after surgery. The MDS of IT was significantly improved compared with IC over time. There were no differences between IT and IC in the volume of tissue lost (IT: 63.8%, IC: 61.8%), spine density or PSD-95 protein level in the striatum. However, dendritic length was increased and arborization was more complex in the contralateral striatum of the IT than the IC group (IT: 1226 μm, IC: 937 μm). These data suggest that treadmill running improves motor function after ICH and that improvement may be related to alteration of dendritic morphology in the striatum.

Motor skills training promotes motor functional recovery and induces synaptogenesis in the motor cortex and striatum after intracerebral hemorrhage in rats

We investigated the effects of motor skills training on several types of motor function and synaptic plasticity following intracerebral hemorrhage (ICH) in rats. Male Wistar rats were injected with collagenase into the left striatum to induce ICH, and they were randomly assigned to the ICH or sham groups. Each group was divided into the motor skills training (acrobatic training) and control (no exercise) groups. The acrobatic group performed acrobatic training from 4 to 28 days after surgery. Motor functions were assessed by motor deficit score, the horizontal ladder test and the wide or narrow beam walking test at several time points after ICH. The number of ΔFosB-positive cells was counted using immunohistochemistry to examine neuronal activation, and the PSD95 protein levels were analyzed by Western blotting to examine synaptic plasticity in the bilateral sensorimotor cortices and striata at 14 and 29 days after ICH. Motor skills training following ICH significantly improved gross motor function in the early phase after ICH and skilled motor coordinated function in the late phase. The number of ΔFosB-positive cells in the contralateral sensorimotor cortex in the acrobatic group significantly increased compared to the control group. PSD95 protein expression in the motor cortex significantly increased in the late phase, and in the striatum, the protein level significantly increased in the early phase by motor skills training after ICH compared to no training after ICH. We demonstrated that motor skills training improved motor function after ICH in rats and enhanced the neural activity and synaptic plasticity in the striatum and sensorimotor cortex.

Early onset of forced impaired forelimb use causes recovery of forelimb skilled motor function but no effect on gross sensory-motor function after capsular hemorrhage in rats

Intensive use of the impaired forelimb promotes behavioral recovery and induces plastic changes of the central nervous system after stroke. However, the optimal onset of intensive use treatment after stroke is controversial. In this study, we investigated whether early forced impaired limb use (FLU) initiated 24h after intracerebral hemorrhage (ICH) of the internal capsule affected behavioral recovery and histological damage. Rats were subjected to ICH via low-dose collagenase infusion or sham stroke. One day after surgery, the ipsilateral forelimbs of half of the ICH and sham rats were casted for a week to induce the use of their contralateral forelimbs. Behavioral assessments were performed on days 10-12 and 26-28 after the surgery and followed by histological assessments. Improvements in skilled reaching and coordinated stepping function were found in the FLU-treated group in comparison with the untreated group after ICH. Additionally, FLU-treated ICH animals showed more normal and precise reaching and stepping movements as compared with ICH control animals. In contrast, FLU did not have a significant impact on gross sensory-motor functions such as the motor deficit score, contact placing response and spontaneous usage of the impaired paw. The volume of tissue lost and the number of spared corticospinal neurons in lesioned motor cortex were not affected by early FLU after ICH. These findings demonstrate the efficacy of early focused use of an impaired limb after internal capsule hemorrhage.

Early constraint-induced movement therapy promotes functional recovery and neuronal plasticity in a subcortical hemorrhage model rat

Constraint-induced movement therapy (CIMT) promotes functional recovery of impaired forelimbs after hemiplegic strokes, including intracerebral hemorrhage (ICH). We used a rat model of subcortical hemorrhage to compare the effects of delivering early or late CIMT after ICH. The rat model was made by injecting collagenase into the globus pallidus near the internal capsule, and then forcing rats to use the affected forelimb for 7 days starting either 1 day (early CIMT) or 17 days (late CIMT) after the lesion. Recovery of forelimb function in the skilled reaching test and the ladder stepping test was found after early-CIMT, while no significant recovery was shown after late CIMT or in the non-CIMT controls. Early CIMT was associated with greater numbers of ΔFosB-positive cells in the ipsi-lesional sensorimotor cortex layers II-III and V. Additionally, we found expression of the growth-related genes brain-derived neurotrophic factor (BDNF) and growth-related protein 43 (GAP-43), and abundant dendritic arborization of pyramidal neurons in the sensorimotor area. Similar results were not detected in the contra-lesional cortex. In contrast to early CIMT, late CIMT failed to induce any changes in plasticity. We conclude that CIMT induces molecular and morphological plasticity in the ipsi-lesional sensorimotor cortex and facilitates better functional recovery when initiated immediately after hemorrhage.

Running exercise enhances motor functional recovery with inhibition of dendritic regression in the motor cortex after collagenase-induced intracerebral hemorrhage in rats

Rehabilitative approaches benefit motor functional recovery after stroke and relate to neuronal plasticity. We investigated the effects of a treadmill running exercise on the motor functional recovery and neuronal plasticity after collagenase-induced striatal intracerebral hemorrhage (ICH) in rats. Male Wistar rats were injected with type IV collagenase into the left striatum to induce ICH. Sham-operated animals were injected with saline instead of collagenase. The animals were randomly assigned to the sham control (SC), the sham exercise (SE), the ICH control (IC), or the ICH exercise (IE) group. The exercise groups were forced to run on a treadmill at a speed of 9 m/min for 30 min/day between days 4 and 14 after surgery. Behavioral tests were performed using a motor deficit score, a beam-walking test and a cylinder test. At fifteen days after surgery, the animals were sacrificed, and their brains were removed. The motor function of the IE group significantly improved compared with the motor function of the IC group. No significant differences in cortical thickness were found between the groups. The IC group had fewer branches and shorter dendrite lengths compared with the sham groups. However, dendritic branches and lengths were not significantly different between the IE and the other groups. Tropomyosin-related kinase B (TrkB) expression levels increased in the IE compared with IC group, but no significant differences in other protein (brain-derived neurotrophic factor, BDNF; Nogo-A; Rho-A/Rho-associated protein kinase 2, ROCK2) expression levels were found between the groups. These results suggest that improved motor function after a treadmill running exercise after ICH may be related to the prevention of dendritic regression due to TrkB upregulation.

Motor Skills Training Improves Sensorimotor Dysfunction and Increases Microtubule-Associated Protein 2 mRNA Expression in Rats with Intracerebral Hemorrhage

BACKGROUND In this study, we examined the effects of motor skills training on the sensorimotor function and the expression of genes associated with synaptic plasticity after intracerebral hemorrhage (ICH) in rats. METHODS Male Wistar rats were subjected to ICH or sham operation. ICH was caused by the injection of collagenase into the left striatum. Rats were randomly assigned to no training, acrobatic training, and sham groups. The acrobatic group performed 5 types of acrobatic tasks from 4 to 28 days after surgery. The forelimb sensorimotor function was evaluated over time using forepaw grasping, forelimb placing, and postural instability tests. At 14 and 29 days after the lesion, we analyzed the mRNA expression levels of microtubule-associated protein 2 (MAP2), brain-derived neurotrophic factor, and growth-associated protein 43 in the bilateral sensorimotor cortex (forelimb area) by real-time reverse transcription-polymerase chain reaction. RESULTS Motor skills training in ICH rats improved the sensorimotor dysfunction significantly from the early phase. The mRNA expression level of MAP2 was upregulated in the ipsilesional sensorimotor cortex by motor skills training at 29 days after the lesion. CONCLUSIONS Our results suggest that sensorimotor functional recovery following motor skills training after ICH is promoted by dendritic growth in the ipsilesional sensorimotor cortex.

Motor Skills Training Enhances α-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid Receptor Subunit mRNA Expression in the Ipsilateral Sensorimotor Cortex and Striatum of Rats Following Intracerebral Hemorrhage

BACKGROUND We investigated the effects of acrobatic training (AT) on expression of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR) subunits in the sensorimotor cortex and striatum after intracerebral hemorrhage (ICH). METHODS Male Wistar rats were divided into 4 groups: ICH without AT (ICH), ICH with AT (ICH + AT), sham operation without AT (SHAM), and sham operation with AT (SHAM + AT). ICH was induced by collagenase injection into the left striatum. The ICH + AT group performed 5 acrobatic tasks daily on days 4-28 post ICH. Forelimb sensorimotor function was evaluated using the forelimb placing test. On days 14 and 29, mRNA expression levels of AMPAR subunits GluR1-4 were measured by real-time reverse transcription-polymerase chain reaction. RESULTS Forelimb placing test scores were significantly higher in the ICH + AT group than in the ICH group. Expression levels of all AMPAR subunit mRNAs were significantly higher in the ipsilateral sensorimotor cortex of rats in the ICH + AT group than in that of rats in the ICH group on day 29. GluR3 and GluR4 expression levels were reduced in the ipsilateral striatum of rats in the ICH group compared with that of rats in the SHAM group on day 14. CONCLUSIONS These changes may play a critical role in motor skills training-induced recovery after ICH.

Forced-use of impaired forelimb increases expression of neurotrophic factors in rats motor cortex and induces recovery of skilled reaching and stepping following internal capsule hemorrhage

P2-f10 Forced-use of impaired forelimb increases expression of neurotrophic factors in rats motor cortex and induces recovery of skilled reaching and stepping following internal capsule hemorrhage Akimasa Ishida 1,2 , Yasuyuki Takamatsu 1, Michiru Hamakawa 1, Keigo Tamakoshi 1, Hideki Hida 2, Kazuto Ishida 1 1 Department Phys Ther., Nagoya University Grad. Sch. Med 2 Neurophysiol. and Brain Sci., Nagoya City University Grad. Sch. Med