The Effects Of Repetitive Transcranial Magnetic Stimulation On Refractory Epilepsy And Expression Of Brain-derived Neurotrophic Factor And Neuropeptide Y.

Part1 The effects of low frequency repetitive transcranial magnetic stimulation on the rats model of refractory epilepsy and expression of brain-derived neurotrophic factor and neuropeptide Y.ObjectiveTo investigate the effects of low frequency repetitive transcranial magnetic stimulation(rTMS) on the rats model of refractory epilepsy(RE) and expression of brain-derived neurotrophic factor(BDNF) and neuropeptide Y(NPY), and to disclose the possible mechanisms.MethodsFifty-four male Wistar rats were equally randomized into rTMS intervention (KA+rTMS), sham-rTMS model(KA+s-rTMS) and normal saline(NS) control (NS+s-rTMS) groups, that is eighteen per group. Refractory epilepsy model was established with injecting by kainic acid(KA) in the CA3 area of left hippocampus using a stereotaxic apparatus, while control group was injected equal NS. The rats in rTMS group received 600 pulses and 0.5Hz, at the stimulation intensity of 0.8 Tesla(T) daily for 2 weeks. Seizure frequency and electroencephalogram(EEG), before and after rTMS treatment, were collected for calculation, compared the spike numbers and relative power of each frequency distribution(%) using the software running on MATLAB 7.0 in different groups and time points. Then the six rats in every group were sacrificed at definite time points(24hour, lweek and 3week) after using a stereotaxic apparatus. The changes in expression of BDNF and NPY in Hippocampus were observed by immunohistochemical technique; the half-quantitative analysis was performed by the counting method to positive neurons and the image analysis software of ImagPro-plus 6.0.Results1. The amount of EEG sharp waves was reduced significantly on the rats model of epilepsy, after low frequency rTMS, and every band power distribution was transformed to optimization in brain function. Compared with KA+s-rTMS group, the amount of T3-lead and T4-lead EEG sharp waves was reduced significantly in KA+rTMS group at both 1w and 3w after operation(all P<0.001). The amount of T4-lead EEG sharp increased with time in both KA+rTMS and KA+s-rTMS groups, and corresponded to T3-lead at 3w after operation(P>0.05). Furthermore, compared with KA+s-rTMS group, low-frequency 8 band power distribution decreased at the same time point, while a band showed significant increase in KA+rTMS group, especially in T3-lead EEG at 3w after operation(P<0.01).2 Immunohistochemistry of BDNF:Compared with KA+s-rTMS group, the number of BDNF immunoreactive positive neurons was reduced significantly in hippocampus, at 24h, 1w and 3w after operation in KA+rTMS group(all P<0.01).3 Immunohistochemistry of tyrosine receptor kinase B(TrkB):Compared with KA+s-rTMS group, the number of TrkB immunoreactive positive neurons was reduced in hippocampus, at 24h, lw and 3w after operation in KA+rTMS group, especially in the time pionts of 1w and 3w(P<0.01).4 Immunohistochemistry of NPY:Compared with KA+s-rTMS group, the number of NPY immunoreactive positive neurons was reduced significantly in hippocampus, at 24h, 1w and 3w after operation in KA+rTMS group(all P<0.001).Conclusion1 Low frequency rTMS can reduce the number of EEG spikes on the rats model of RE, and improve epileptic EEG discharges. It can protect the neuron in hippocampus, control the astrocyte reactive and mitigate the hippocampal sclerosis.2 The number of T4-lead EEG spikes increases with time on the rats model of RE, and the background rhythm is bad in the non-injection side. Epileptiform discharge in the ipsilateral hippocampus may affect the contralateral area.3 Low frequency rTMS can change evidently the number of BDNF, TrkB and NPY immunoreactive positive neurons. The expression of BDNF, TrkB and NPY can related closely with the pathogenesis of epilepsy.4 The analysis of EEG signals based on MATLAB 7.0 can effectively reduce the accurate information, and can distinguish the spikes from the background waves effectively and correctly. Part2 The clinical exploration of repetitive transcranial magnetic stimulation in refractory epilepsy.ObjectiveTo observe the effectiveness of low-frequency and subthreshold rTMS on patients with RE.MethodsTwelve subjects with refractory and focal epilepsy were involved. rTMS as a treatment with 600 pulses, intensity of 90% motor resting threshold and 0.5Hz frequency was administrated once per day,5 days as one course.5 of 12 accepted the second course treatment. The number of seizure frequency, seizure days, and seizure latency, pre-and-pro treatment were measured and compared. Meanwhile, EEG was collected for calculation, compared epileptic spikes discharges in the EEG and relative power of each frequency distribution(%) using the software running on MATLAB 7.0.ResultsrTMS significantly decreased the frequency and days of seizures after 5 days of the first treatment among all 12 paients (t=2.450,P=0.032; t=2.797, P=0.017); and prolonged seizure latency in eight patients. Furthermore, high-frequencyβband power distribution showed significant increase (t=-2.703, P=0.021), especially inαband (t=-3.680, P=0.004); while low-frequency 8 band decreased (t=3.047, P=0.011). And the amount of EEG sharp waves was reduced significantly (t=2.411, P=0.035). Compared with the first course, these indexes were improved in the second treatment. The changes ofδandαbands were great, especially 8 band decreased to 2.08 times; this meaned that EEG background waves were improved evidencely.ConclusionLow-frequency and subthreshold rTMS can decrease the events of epileptic seizures, prolong seizure latency and improve epileptic EEG discharges. As a new method in the area of non-drug-induceded neuro-modulation, low-frequency rTMS is safe and effective treatment for refractory epilepsy. It showed illustrates a good prospect of clinical application.