Disruption of the neurogenic potential of the dentate gyrus in a mouse model of temporal lobe epilepsy with focal seizures.
Adult hippocampal neurogenesis is enhanced in response to multiple stimuli including seizures. However, the relationship between neurogenesis and the development of temporal lobe epilepsy (TLE) remains unclear. Unilateral intrahippocampal injection of kainate in adult mice models the morphological characteristics (e.g. neuronal loss, gliosis, granule cell dispersion and hypertrophy) and occurrence of chronic, spontaneous recurrent partial seizures observed in human TLE. We investigated the influence of a kainate-induced epileptogenic focus on hippocampal neurogenesis, comparing neural stem cell proliferation following status epilepticus and spontaneous recurrent partial seizures. Cell proliferation in the subgranular zone was transiently increased bilaterally after kainate treatment. As a result, neurogenesis was stimulated in the contralateral dentate gyrus. In contrast, the epileptic hippocampus exhibited a strongly reduced neurogenic potential, even after onset of spontaneous recurrent partial seizures, possibly due to an alteration of the neurogenic niche in the subgranular zone. These results show that neurogenesis does not contribute to the formation of the epileptic focus and may be affected when dispersion of dentate gyrus granule cells occurs. Therefore, in patients with TLE, hippocampal sclerosis and granule cell dispersion may play a significant role in disrupting the potential for hippocampal neurogenesis.
Kralic
Jason E
JE
Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, CH -8057 Zurich, Switzerland.
Ledergerber
Debora A
DA
Fritschy
Jean-Marc
JM
D000818:Animals; D001973:Bromodeoxyuridine / Q000378:metabolism; D002452:Cell Count; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D018891:Dentate Gyrus / Q000166:cytology*; D004195:Disease Models, Animal; D004569:Electroencephalography / Q000187:drug effects; D004833:Epilepsy, Temporal Lobe / Q000139:chemically induced / Q000150:complications / Q000473:pathology*; D007839:Functional Laterality; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism; D007150:Immunohistochemistry / Q000379:methods; D007608:Kainic Acid; D008297:Male; D051379:Mice; D009474:Neurons / Q000187:drug effects / Q000502:physiology*; D010751:Phosphopyruvate Hydratase / Q000378:metabolism; D012640:Seizures / Q000139:chemically induced / Q000150:complications / Q000473:pathology*; D013997:Time Factors
D005904:Glial Fibrillary Acidic Protein; D010751:Phosphopyruvate Hydratase; D001973:Bromodeoxyuridine; D007608:Kainic Acid