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Objective To study the effect of hyperbaric oxygen (HBO) on the proliferation and differentiation of neural stem cells (NSCs) in rats after middle cerebral artery occlusion (MCAO).Methods Seventy-two adult,male,Sprague-Dawley rats were randomly divided into a control (CON) group,a hyperbaric air (HBA) group,a normobaric oxygen (NBO) group and a hyperbaric oxygen (HBO) group.All were subjected to MCAO.Rats in the CON group did not receive any treatment; those in the other groups were treated with HBA,NBO or HBO daily beginning 2 hours after the operation.Western blotting was applied to detect the expression of nestin,MAP2 and GFAP at 2,3,7 and 14 days after the MCAO.Results The expression of nestin in the HBO group was significantly higher than in the other groups on the 3rd,7th and 14th days.It peaked at day 3 but remained high until day 14.Similarly,expression of MAP2 was significantly higher than in the other groups at least until day 14.GFAP expression was significantly lower than in the other groups.Conclusion HBO can increase neural stem cell proliferation and neuronal differentiation,and inhibit the proliferation of astrocytes.
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Objective To investigate the effects of 20 Hz repetitive transcranial magnetic stimulation (rTMS) with different intensities on neurobehavior and expression of glial fibrillary acidic protein (GFAP) in ischemic penumbra of rats with cerebral infarction,so as to explore the probable mechanism. Methods Forty-three rats were randomly divided into a blank control group( n =7 ),a model control group( n =7),a sham stimulation control group(n =8) and a rTMS group (n =21) ; the rTMS group was further subdivided into 3 subgroups:80％ MT subgroup,100％ MT subgroup and 120％ MT subgroup,with 7 rats in each subgroup.The cerebral infarction model was established by right middle cerebral artery occlusion (MCAO) in each group except the blank control group.The 3 rTMS subgroups were given 14 successive blocks of 20 Hz rTMS with corresponding intensity.The sham stimulation control group received sham treatment (without any output).The model control group was given no stimulation,and the blank control group did not receive any special treatment.Functional assessments were performed at 3 different time points.After 14-day treatment,the expression of GFAP proteins in ischemic penumbra were detected by immunohistochemistry technique. Results Functional outcome reflected from 3 behavioral tests in 100％ MT subgroup after 14-day stimulation was better than 1 day after operation,while in the other rTMS subgroups functional outcomes were just better in 2 behavioral tests.The expressions of GFAP in 3 rTMS subgroups were all less than that in model control group. Conclusions The 20 Hz rTMS with 80％ MT and 100％ MT might be safe and effective to improve the functional outcome in rats with acute cerebral infarction,especially 100％ MT.Decrease of expression of GFAP in ischemic penumbra might be one of the mechanisms of beneficial effects of rTMS in ischemia brain injury.
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Objective To investigate the effects of high-frequency repetitive transcranial magnetic stimulation (rTMS) at different intensities on the ultrastructure of an ischemic brain penumbra and the expression of brainderived neurotrophic factor (BDNF) using rats with permanent middle cerebral artery occlusion (MCAO).Methods Forty-two rats were randomly divided into a blank control group,an MCAO model control group,a sham stimulation control group and an rTMS group.The rTMS group was divided further into 3 subgroups:an 80％ of motor threshold (MT) subgroup,a 100％ of MT subgroup and a 120％ of MT subgroup.The cerebral infarction model was established by right MCAO.rTMS treatment was given 24 hours after the MCAO model was successfully established.The rTMS group and sham stimulation control group were given 20 Hz rTMS with the planned intensities.The MCAO model control group was not given any stimulation.After 14 days of treatment,transmission electron microscopy,immunohistochemical and Western blotting ( WB ) methods were used to investigate the ultrastructure of the ischemic penumbra and the expression of BDNF.Results Damage reflected in the ultrastructure in the 3 rTMS subgroups was less than in the model control group and the sham stimulation control group.Expression of BDNF protein increased significantly in 100％ of the MT group and blank control group rats as compared with that in the sham stimulation control group,while the blank control group and the 3 rTMS subgroups had no statistically significant difference in comparison with the MCAO model control group.The expression of BDNF protein had no statistically significant difference between any of the groups.Conclusion 20 Hz rTMS might,especially at 100％ of the MT,promote the recovery of the ultrastructure of neural tissues in the ischemic penumbra after acute cerebral infarction and enhance the expression of BDNF in the ipsilesional hemisphere.This may be one of the important mechanisms of rTMS's effectiveness in the treatment of ischemic stroke.