Establishment of the Model of Status Epilepticus in Rats

Lithium chloride (Sigma, USA) and pilocarpine (Sigma, USA) were used to induce SE (García-García et al., 2017). Rats were intraperitoneally injected with 127 mg/kg lithium chloride in 0.9% saline 20–24 h before pilocarpine injection. Scopolamine (1 mg/kg in 0.9% saline) was injected intraperitoneally 30 min before pilocarpine injection to reduce peripheral side effects. Intraperitoneal injection of 30 mg/kg pilocarpine was performed in the SE and AST groups, and saline was injected into the Normal group as a replacement for lithium chloride and pilocarpine. Electroencephalogram (EEG) monitoring was performed on rats during SE to identify a seizure (Figure 1), and behavioral seizures were scored using a modified Racine scale (Ishida et al., 1992). Seizures were graded using the following classification: I—standing still or wet dog shakes; II—nodding and chewing rhythmically; III—unilateral forelimb clonic seizure; IV—bilateral forelimb clonic and convulsive seizure with standing; and V—receding, tumbling, with a generalized tonic-clonic seizure. SE models were regarded as successfully kindled when the rats developed seizure scoring grade IV-V within 30 min and exhibited a sustained state. If the rat did not develop seizure scoring grade IV-V, then rats were injected (i.p.) with 10 mg/kg pilocarpine every 30 min until the seizure reached grade IV-V. No rat received more than 60 mg/kg pilocarpine. Diazepam (10 mg/kg, i.p.) was administered after a seizure lasted 60 min to terminate the seizure. The criteria for SE model success included EEG showing seizure, seizure grade reaching IV-V and seizure lasting for over 30 min. A total of 104 rats were used. Twenty-two rats were injected with saline for the Normal group, and 82 rats were injected with pilocarpine to induce SE. Sixty-three rats were successfully induced SE rats (success rate 76.83%), and these rats were randomly divided into an SE group (31 rats) and AST group (32 rats). Nine rats failed (failure rate 10.98%), and ten rats died (mortality rate 12.20%).

EEG changes of rats pro-SE and post-SE.(A) The EEG of rats pro-SE and post-SE; (B) the EEG relative power of rats pro-SE and post-SE.The EEG relative power (μV²) of SE rats was significantly increased (**p < 0.01 vs. Normal).