Status epilepticus severity influences the long-term outcome of neurogenesis in the adult dentate gyrus.
Status epilepticus (SE) is characterized by continual seizure activity that can vary widely in the intensity of convulsions. We induced seizures by applying continuous electrical stimulation to the hippocampus in adult rats to explore the effects of three different SE states on neurogenesis and neuronal death in the hippocampus. Rats exhibiting the most severe SE state (fully convulsive) demonstrated profound increases in cell proliferation in the dentate gyrus (DG) at 1 week post-insult, but the majority of the new neurons had died at 4 weeks. In contrast, rats exhibiting less severe SE states (ambulatory or masticatory, partial convulsive) had the same degree of cell proliferation at 1 week, but most new neurons survived at 4 weeks. As compared to partially convulsive SE rats, fully convulsive SE rats had significantly greater DG pathology. Our data indicate that SE of varying severity triggers similar short-term proliferation of neural progenitors, but that the long-term outcome of neurogenesis is influenced by the degree of insult-induced degeneration in the DG tissue environment.
Mohapel
Paul
P
Section of Restorative Neurology, Wallenberg Neuroscience Center, SE-221 84 Lund, Sweden. paul.mohapel@neurol.lu.se
Ekdahl
Christine T
CT
Lindvall
Olle
O
D000818:Animals; D016923:Cell Death / Q000502:physiology; D002454:Cell Differentiation / Q000502:physiology; D002455:Cell Division / Q000502:physiology; D002470:Cell Survival / Q000502:physiology; D018891:Dentate Gyrus / Q000254:growth & development* / Q000473:pathology / Q000503:physiopathology; D004195:Disease Models, Animal; D004558:Electric Stimulation; D008297:Male; D009410:Nerve Degeneration / Q000473:pathology / Q000503:physiopathology*; D009416:Nerve Regeneration / Q000502:physiology*; D009473:Neuronal Plasticity / Q000502:physiology*; D009474:Neurons / Q000166:cytology / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D011930:Reaction Time / Q000502:physiology; D012640:Seizures / Q000473:pathology / Q000503:physiopathology; D013226:Status Epilepticus / Q000473:pathology / Q000503:physiopathology*; D013234:Stem Cells / Q000166:cytology / Q000502:physiology