Effects Of DBS On Electrophysiological Changes Of Hippocampus And Expression Of The Extrasynaptic GABA Receptor In Epileptic Rats

Objective To approach the effectiveness of STN DBS treatment on electrophysiological changes of hippocampus and the distribution and expression of the delta subunit of the GABA receptor in the kainic acid induced rat model.Methods SD rats (n=24,male) were randomized into the blank control group, epilepsy group and DBS treatment group. Implanted the injection tube in the hippocampus and recording and stimulating electrodes in the subthalamic nucleus by stereotaxic apparatus, established the kainate rat model of epilepsy in the free state, given the high-frequency electrical stimulation to the treatment group for DBS therapy, we observed the changes in animal behavior. The neuron electrophysiological signal of rats in the hippocampus were recorded by the Alpha Omega EEG signal acquisition system during the seizures and after the DBS, analysis the time domain and frequency domain of the EEG signal by the NeuroExplorer software, observed the hippocampal physiology pattern by DBS treatment. Given 10 days DBS treatment, all the rats brain tissue was obtained to observer the DBS treatment effects on the epileptic hippocampal neurons by Nissl staining , while use of immunohistochemistry to detect the distribution and expression ofδsubunit containing extrasynaptic GABA receptor in the seizure states and the DBS treatments.Result 1. There was no seizures in the normal control group. The seizure frequency in the DBS treatment group(6.01±4.87, n = 8) was significantly lower than the epilepsy control group(17.31±4.59, n = 8) (p <0.05).2. Both the low and high frequency components of the abnormal discharge were inhibited in the earlier and later stages respectively in the hippocampus of epileptic rat. However, DBS treatment does not change the spike frequency of the hippocampal neurons.3. Nissl staining showed that hyperplasia of hippocampal neurons loss and glial cells in the STN DBS treatment group (463.62±38.41, n = 8) lighter than the epilepsy group (357.12±20.50, n = 8) (P <0.05).4. Compared with the blank control group(IOD=30.96±2.73 in hippocampus and IOD=32.85±2.35 in thalamencephal) and the epilepsy control group(IOD=12.31±1.72 in hippocampus and IOD=22.39±1.94 in thalamencephal), the immunohistochemistry results showed that DBS induced a significant increase of the expression of the delta subunit of the GABA receptor in the thalamencephal (IOD=35.91±3.97) (P<0.05), while inhibited the decrease of the delta subunit of the GABA receptor in hippocampus (IOD=22.74±2.08)(P<0.05).Conclusion STN DBS treatment can inhibit the epilepsy and alter the electrophysiological patter of Hippocampus by increasing the expression of the delta subunit of the GABA receptor in the thalamencephal and hippocampus.