title: Quantitative hippocampal structural changes following electroconvulsive seizure treatment in a rat model of depression.
abstract: OBJECTIVE
  The pathophysiology of depression and the effects of antidepressant treatment are hypothesized to be related to hippocampal structural changes. This study aims to investigate the effect of electroconvulsive seizures on behavior and hippocampal structure in a rat model of depression.
  
  
  METHODS
  Flinders Sensitive Line (FSL) and Flinders Resistant Line (FRL) rats were treated daily for 10 days with either electroconvulsive seizures or sham treatment. The behavior was evaluated using the forced swim test. Design-based stereological methods were used to quantify the hippocampal volume and the numbers of neurons and glial cells in specific hippocampal subregions.
  
  
  RESULTS
  The basal level of hippocampal volume and neuron number differed significantly between the two rat strains, and a trend toward the FSL strain having more glial cells was found. The structural differences found between the sham-treated animals were counteracted by electroconvulsive seizure (ECS) treatment, which also normalized the behavior. ECS treatment increased the number of glial cells in hilus significantly in the FRL rats and with the same tendency for the FSL rats.
  
  
  CONCLUSIONS
  Our results indicate that along with hippocampal neurogenesis, gliogenesis may also be involved in the pathophysiology of depression and in the effect of antidepressant treatment. The underlying mechanisms remain unknown, and further investigations are required to clarify whether the structural changes are necessary to induce a therapeutic effect of antidepressant treatment or if they rather represent an epiphenomenon.
authors.affiliation: Stereology and EM Laboratory, Centre for Stochastic Geometry and Advanced Bioimaging, Aarhus University Hospital, DK-8000 Aarhus C, Denmark.
authors.forename: Susanne S
authors.initials: SS
authors.lastname: Kaae
authors.forename: Fenghua
authors.initials: F
authors.lastname: Chen
authors.forename: Gregers
authors.initials: G
authors.lastname: Wegener
authors.forename: Torsten M
authors.initials: TM
authors.lastname: Madsen
authors.forename: Jens R
authors.initials: JR
authors.lastname: Nyengaard
mesh_terms: D000818:Animals; D049109:Cell Proliferation; D003866:Depressive Disorder / Q000473:pathology* / Q000628:therapy*; D004195:Disease Models, Animal; D004565:Electroconvulsive Therapy; D006624:Hippocampus / Q000473:pathology* / Q000503:physiopathology; D008297:Male; D055495:Neurogenesis; D009457:Neuroglia / Q000473:pathology; D051381:Rats; D011919:Rats, Inbred Strains; D013550:Swimming