Alleviation Of Seizures And Retarded Behavior Of Epileptic Rats Induced With Ferric Chloride By Cortical Electrical Stimulation

Epilepsy is a chronic neurological disorder invoked by excessive abnormal discharge of brain neurons and characterized by recurrent seizures. Its prevalence is around 0.5% to 1%. A variety of factors can lead to the occurrence of seizures, such as intracranial infection, intracranial tumor, encephalodysplasia, brain trauma, cerebral hemorrhage, brain injury, etc. Although the outcome of pharmacological treatment is relatively good, seizures are not satisfactorily controlled with anti-epileptic drugs in about 30% patients. For these patients, surgery can be a good option. However, identifiable epileptogenic foci are hard to find in many patients with refractory epilepsy, alternative therapies are needed. Emerge of electrical stimulation therapy rekindles the hopes for treatment of patients with refractory epilepsy. Previous experiments have shown that electrical stimulation therapy is effective for control of epilepsy and other brain functional diseases. A number of studies have confirmed that the low-frequency electrical stimulation can inhibit epileptic seizures of amygdala kindling animals. In recent years, numbers of studies on brain slices indicate that electrical stimulation, in particular low frequency electrical stimulation, can inhibit epileptic discharges.The purpose of this experiment was to study the effects of cortical electrical stimulation on seizures and behavior of epileptic rats, and to explore its effective mechanism. Thirty-two male SD rats were randomly assigned into four groups. Eight rats accepted no treatment. Other rats accepted open-skull surgery. Among them, eight rats were injected saline in the right sensorimotor cortex, eight rats were injected ferric chloride to induce epilepsy and the other eight rats were injected ferric chloride and accepted electrical (1Hz, 0.1mA) stimulation for 2 hours per day for seven days. All rats were inserted electrodes during the surgery for electrocephalography (EEG). Behaviors in water maze and open-field were used to exam their learning abilities and emotional responses. Expression levels of brain-derived neurotrophic factor (BDNF) in cortical and hippocampal samples were examined by western blot. The results indicate that electrical stimulation significantly decreased the number and grade of seizures and improved rat behavior compared with rats in the model group (p<0.05). In addition, electrical therapy enhanced BDNF expression in cortical sample and reduced BDNF expression in hippocampal samples compared with epileptic rats. Electron microscopy showed less damage and ultrastructural changes in neurons in the electrical stimulated rats. Taking together, the study indicates that low-frequency electrical stimulation can effectively inhibit ferric chloride induced epileptic seizures in rats and improve the learning and memory capacities and environmental adaptability of epileptic rats and this neuron protective effect may be caused by the alteration of BDNF expression in rat brain.