Effects Of Low-Frequency Repetitive Transcranial Magnetic Stimulation On Learning-Memory Function And The Expression Of Astrocytes In The Cerebral Infarction Rats

Objective:To observe the effect of low-frequency repetitive transcranial magnetic stimulation to improve learning and memory function and the expression of astrocytes in the cerebral infarction rats.Further more,we wanted to investigate the mechanism of low frequency rTMS on the recovery of learning and memory impairment after cerebral infarction.Methods:The study contains five group:the Control group?Model group?40%output intensity group?60%output intensity group?80%output intensity group,all groups were randomly divided by One hundred male SD rats.And each group were divided into 7d andl4d two subgroups.Model of middle cerebral artery occlusion(MCAO)was established,from the second day low-frequency(1 Hz)rTMS was performed on rats for 7 d and 14 d respectively.In 6th/9th day after operation,the learning and memory function of every group were tested through a kind of multi-functional reaction tank and water maze test.In 7th/14th day after operation,MCAO rat's hippocampal CA1 and CA3 area AST activation,migration ability were observed by immunofluorescence.Results:1?The results of multi-functional reaction tank revealed that(1)?step down latency(SDL1):The SDL1 of the model group shortened distinctly,it was significantly smaller than Control group and other three rTMS groups(P<0.05);The three rTMS groups and the Control group were no obvious difference for each of the other(P>0.05).?The number of error(N1):The error times of the model group was higher,compared with the Control group and other three rTMS groups(P>0.05).(2)?step down latency(SDL2)The SDL2 of the model group shortened distinctly,it was significantly smaller than Control group and 60%output intensity(P<0.05);the three rTMS groups and Control group were no obvious difference for each other(P>0.05).?The number of error(N2)The error times of the model group was higher,compared with the Control group and other three rTMS groups(P>0.05).The three rTMS groups and Control group were no obvious difference for each other(P>0.05).2.The Morris water maze test result(1)The navigation task ?The 1st day The average distance swimming of the model group?40%group and 80%group were shorter than the Control group(P<0.05);The average distance swimming of the 60%group and the Control group were no obvious difference(P>0.05).The average distance swimming of the model group and the three rTMS groups,the former was shorter(P<0.05).?The 2nd day The average distance swimming of the Control group and the rTMS groups were longer than the model group(P<0.05);the Control group and the rTMS groups were no obvious difference between each other(P>0.05).?The 3rd day The average distance swimming of the Control group were longer than the model group and 80%group(P<0.05);the Control group?40%group and 60%group were no statistics difference between each of the other(P>0.05).The average distance swimming of the model group was shorter than the 60%group(P<0.05).The 40%group,60%group and 80%group were no significant difference between each other(P>0.05).?The 4th day The average distance swimming of the model group was shorter than the Control group and 60%group(P<0.05);the 40%group and 80%group were no statistics difference(P>0.05).(2)The probe task ?tP/tT The tP/tT of the Control group was higher than the model group?40%group and 80%group(P<0.05);but the model group?40%group and 80%group were no obvious difference between each other(P>0.05).The Control group and 60%group were no statistics difference(P>0.05).The tP/tT of the model group?40%group and 80%group were smaller than the 60%group(P<0.05).?dP/dT The dP/dT of the Control group was higher than the model group?40%group and 80%group(P<0.05);but the model group?40%group and 80%group were no obvious difference between each other(P>0.05).The Control group and 60%group were no obvious difference(P>0.05).The dP/dT of the model group?40%group and 80%group were smaller than the 60%group(P<0.05).3.Immunofluorescence results,At 7th day and14th day after ischemia,the expression of AST in the 60%group was higher than the 40%and 80%group in area CA1 and CA3 of the hippocampus of the ischemia cerebral(P<0.05).It has no obvious statistical differences,either 7d or 14d(P<0.05).Conclusion:The low-frequency repetitive transcranial magnetic stimulation could increase learning and memory function and the expression of astrocytes in the cerebral infarction rats.Therefore,we speculated that the rTMS promotes the recovery mechanism of learning and memory function in rats with cerebral infarction might be correlated with it increase the expression of astrocytes in the cerebral infarction rats.It is possible to have a certain relationship with the output intensity of the magnetic stimulation.