Proliferation changes in hippocampal neurons following pilocarpine-induced intractable epilepsy in adult rats

Epilepsy can lead to the changes in neurons residing in the dentate gyrus. The present study aimed to observe the cell dividing features following epilepsy in adult rat hippocampi,and to study difference in cell proliferation between adult rats with common epilepsy and intractable epilepsy. Adult,male,Sprague Dawley rats were randomly divided into control(n = 8,treatment with normal saline) and three experimental groups: common epilepsy(n = 33) ,intractable epilepsy(n = 11) ,and drug-responsive(n = 25) . Pilocarpine(15 mg/kg) was intraperitoneally administered to establish epilepsy in the three experimental groups. Rats that developed epilepsy were treated with chloral hydrate. Rats that did not exhibit spontaneous seizures were enrolled in the common epilepsy group,and rats with spontaneous seizure were included in the spontaneous seizure group. At 6 hours after epileptic attack termination,rats were intraperitoneally injected with bromodeoxyuridine(BrdU;50 mg/kg) ,an optimal marker for labeling cell proliferation in vivo,four times. Immunohistochemistry results at 48 hours after BrdU injection indicated that the number of BrdU-positive cells was the highest in the common epilepsy group,followed by the control group,and lastly the intractable group(P < 0.01) . In addition,the number of BrdU-positive cells in the common epilepsy group was similar to the drug-responsive group. The present findings demonstrated that intractable epilepsy led to decreased hippocampal neurons in adult rats when compared to common epilepsy.