Intervention Mechanism Of Melatonin And Electroacupuncture On Sleep In Mouse Model Of Acute Epilepsy Induced By Kainic Acid

Objective: The two-way effect of epilepsy and sleep has been paid attention to as early as the nineteenth century,accumulating clinical and basic studies have also shown that epilepsy affects the patients’ sleep.The primary or secondary insomnia also is thought as one of the risk factors that induce epilepsy,or cause the aggravation of epilepsy,accelerate the progression of the disease.The drugs used in the guidelines of the International League Against Epilepsy also have an effect on sleep,so the improvement of sleep in epilepsy patients needs urgent attention.The treatment with melatonin and electroacupuncture of insomnia has achieved a very good effect,but the mechanism of electroacupuncture treatment has not been fully understood.The combined treatment of melatonin and anti-epileptic drugs has been found effectively in clinical,also electroacupuncture Neiguan(PC6)and Sanyinjiao(SP6)points have a function of nourishing blood and calming nerves.The hippocampal brain region is closely related to epilepsy,so this study is intended to recording the firing information of population neurons in hippocampal CA1 region.To explore the neuron firing pattern during the sleep of mice with epilepsy,and the change of pattern and characteristics after melatonin and electroacupuncture intervention,lay the foundation for the study of the neural mechanism of melatonin and electro-acupuncture intervention in treating epilepsy.Methods: The 2-4-month-old C57BL/6J mice were selected,and given intraperitoneal injection of kainic acid to induce acute temporal lobe epilepsy animal model.The intervention method of electro-acupuncture of bilateral Neiguan and Sanyinjiao points with melatonin intraperitoneal injection.The experiments were divided into control group,epilepsy model non-treatment group,epilepsy model melatonin group,epilepsy model electro-acupuncture group,epilepsy model mouse restrained group.The model inducing(or control treatment),intervention(or control treatment),sodium barbiturate induces sleep were given in every 30 min separately.To observe the behavioral of mice(HD video recording),the electrophysiological information was recording simultaneously,then combining the behavioral data with firing pattern to explore the mechanism.Results:According to Racine’s epilepsy evaluation criteria,a stable acute temporal lobe epilepsy animal model was obtained after kainic acid intraperitoneal injection.The total sleep duration of the epilepsy model non-treatment group was 1112 ±124 s,the delay of sleep was 433±32 s.With the 30mg/kg melatonin and 20 min 1-5 Hz electro-acupuncture treatment,the sleep duration was extended to 5256 ±463s and 2832 ±81 s,respectively,and the electro-acupuncture effectively shortened the delay of sleep to 238±28 s.Further,by employing the neuron multi-channel in vivo recording technology,we recorded five different firing patterns in mice hippocampal CA1 region with acute temporal lobe epilepsy.According to the variation of firing frequency,neurons in the hippocampal CA1 region of mouse epilepsy model can be shown as the excitability enhancement and inhibition activity.From the Z-score of population neuron firing frequency,the neuron’s firing showed significant inhibition first,and then with a slow rebound after epilepsy modeling.The melatonin treatment could reduce the rise rate of neuron firing frequency during the rebound stage,then the firing frequency decreased again after sodium barbiturate induced sleep,and then the firing frequency slowly rebounded at the end of the sleep stage.During the sleep latency,the decrease rate of neuron firing rate varies.We found that the frequency of local field potential is closely related to animal behavior.The melatonin could significantly reduce the frequency of local field potential oscillation in the mice model of epilepsy during sleep,as well as the electro-acupuncture aggravated the short-term sharp increase of local field potential in acute epilepsy period.Based on the condition of behavioral righting reflex,in the transition stage of sleep and wakefulness,there was a characteristic local field potential oscillation in the mice model of epilepsy: first a large amplitude and low frequency firing and then a significant inhibition.In addition,we found 35-40 Hz low-frequency γ wave oscillations 15 minutes after modeling.In all groups,there was an inhibition of the band above 35 Hz and the enhancement of δ(0.5-3Hz)and θ(4-8Hz)oscillation.Conclusion: Through behavioral testing,melatonin and low frequency electroacupuncture for epilepsy animal models have the effect of prolonging the total sleep duration,electro-acupuncture intervention can also shorten the delay period to sleep.Through the results of in vivo electrophysiology experiments,the local field potential showed short-term sharp increase for the acute period of epilepsy,and this enhancement was alleviated by melatonin treatment but interestingly,it was worsened with the electroacupuncture treatment.So by using the electro-acupuncture to treat epilepsy should pay attention to avoid the acute stage of epilepsy and reduce the frequency of electroacupuncture.