title: Altered hippocampal myelinated fiber integrity in a lithium-pilocarpine model of temporal lobe epilepsy: a histopathological and stereological investigation.
abstract: The damage of white matter, primarily myelinated fibers, in the central nervous system (CNS) of temporal lobe epilepsy (TLE) patients has been recently reported. However, limited data exist addressing the types of changes that occur to myelinated fibers inside the hippocampus as a result of TLE. The current study was designed to examine this issue in a lithium-pilocarpine rat model. Investigated by electroencephalography (EEG), Gallyas silver staining, immunohistochemistry, western blotting, transmission electron microscopy, and stereological methods, the results showed that hippocampal myelinated fibers of the epilepsy group were degenerated with significantly less myelin basic protein (MBP) expression relative to those of control group rats. Stereological analysis revealed that the total volumes of hippocampal formation, myelinated fibers, and myelin sheaths in the hippocampus of epilepsy group rats were decreased by 20.43%, 49.16%, and 52.60%, respectively. In addition, epilepsy group rats showed significantly greater mean diameters of myelinated fibers and axons, whereas the mean thickness of myelin sheaths was less, especially for small axons with diameters from 0.1 to 0.8µm, compared to control group rats. Finally, the total length of the myelinated fibers in the hippocampus of epilepsy group rats was significantly decreased by 56.92%, compared to that of the control group, with the decreased length most prominent for myelinated fibers with diameters from 0.4 to 0.8µm. This study is the first to provide experimental evidence that the integrity of hippocampal myelinated fibers is negatively affected by inducing epileptic seizures with pilocarpine, which may contribute to the abnormal propagation of epileptic discharge.
authors.affiliation: Lab of Pediatric Neurology, Ministry of Education Key Laboratory of Child Development and Disorders, Key Laboratory of Pediatrics in Chongqing, Chongqing International Science and Technology Cooperation Center for Child Development and Disorders, Children's Hospital of Chongqing Medical University, Chongqing, PR China.
authors.forename: Yuanzhen
authors.initials: Y
authors.lastname: Ye
authors.forename: Jiajia
authors.initials: J
authors.lastname: Xiong
authors.forename: Jun
authors.initials: J
authors.lastname: Hu
authors.forename: Min
authors.initials: M
authors.lastname: Kong
authors.forename: Li
authors.initials: L
authors.lastname: Cheng
authors.forename: Hengsheng
authors.initials: H
authors.lastname: Chen
authors.forename: Tingsong
authors.initials: T
authors.lastname: Li
authors.forename: Li
authors.initials: L
authors.lastname: Jiang
mesh_terms: D000818:Animals; D015153:Blotting, Western; D003292:Convulsants / Q000633:toxicity; D004195:Disease Models, Animal; D004569:Electroencephalography; D004833:Epilepsy, Temporal Lobe / Q000139:chemically induced / Q000473:pathology* / Q000503:physiopathology; D006624:Hippocampus / Q000473:pathology*; D007150:Immunohistochemistry; D008094:Lithium / Q000633:toxicity; D008297:Male; D046529:Microscopy, Electron, Transmission; D009413:Nerve Fibers, Myelinated / Q000473:pathology*; D010862:Pilocarpine / Q000633:toxicity; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D003292:Convulsants; D010862:Pilocarpine; D008094:Lithium