title: Age, environment, object recognition and morphological diversity of GFAP-immunolabeled astrocytes.
abstract: BACKGROUND
  Few studies have explored the glial response to a standard environment and how the response may be associated with age-related cognitive decline in learning and memory. Here we investigated aging and environmental influences on hippocampal-dependent tasks and on the morphology of an unbiased selected population of astrocytes from the molecular layer of dentate gyrus, which is the main target of perforant pathway.
  
  
  RESULTS
  Six and twenty-month-old female, albino Swiss mice were housed, from weaning, in a standard or enriched environment, including running wheels for exercise and tested for object recognition and contextual memories. Young adult and aged subjects, independent of environment, were able to distinguish familiar from novel objects. All experimental groups, except aged mice from standard environment, distinguish stationary from displaced objects. Young adult but not aged mice, independent of environment, were able to distinguish older from recent objects. Only young mice from an enriched environment were able to distinguish novel from familiar contexts. Unbiased selected astrocytes from the molecular layer of the dentate gyrus were reconstructed in three-dimensions and classified using hierarchical cluster analysis of bimodal or multimodal morphological features. We found two morphological phenotypes of astrocytes and we designated type I the astrocytes that exhibited significantly higher values of morphological complexity as compared with type II. Complexity = [Sum of the terminal orders + Number of terminals] × [Total branch length/Number of primary branches]. On average, type I morphological complexity seems to be much more sensitive to age and environmental influences than that of type II. Indeed, aging and environmental impoverishment interact and reduce the morphological complexity of type I astrocytes at a point that they could not be distinguished anymore from type II.
  
  
  CONCLUSIONS
  We suggest these two types of astrocytes may have different physiological roles and that the detrimental effects of aging on memory in mice from a standard environment may be associated with a reduction of astrocytes morphological diversity.
authors.affiliation: Laboratório de Investigações Em Neurodegeneração e Infecção, Instituto de Ciências Biológicas, Universidade Federal do Pará, Hospital Universitário João de Barros Barreto, Rua dos Mundurucus 4487, Guamá, Belém, Pará, CEP 66073-000, Brazil.|Laboratory of Experimental Neuropathology, Department of Pharmacology, University of Oxford, Oxford, England, UK.
authors.forename: Daniel Guerreiro
authors.initials: DG
authors.lastname: Diniz
authors.affiliation: Laboratório de Investigações Em Neurodegeneração e Infecção, Instituto de Ciências Biológicas, Universidade Federal do Pará, Hospital Universitário João de Barros Barreto, Rua dos Mundurucus 4487, Guamá, Belém, Pará, CEP 66073-000, Brazil.
authors.forename: Marcus Augusto
authors.initials: MA
authors.lastname: de Oliveira
authors.affiliation: Laboratório de Investigações Em Neurodegeneração e Infecção, Instituto de Ciências Biológicas, Universidade Federal do Pará, Hospital Universitário João de Barros Barreto, Rua dos Mundurucus 4487, Guamá, Belém, Pará, CEP 66073-000, Brazil.
authors.forename: Camila Mendes
authors.initials: CM
authors.lastname: de Lima
authors.affiliation: Laboratório de Investigações Em Neurodegeneração e Infecção, Instituto de Ciências Biológicas, Universidade Federal do Pará, Hospital Universitário João de Barros Barreto, Rua dos Mundurucus 4487, Guamá, Belém, Pará, CEP 66073-000, Brazil.
authors.forename: César Augusto Raiol
authors.initials: CA
authors.lastname: Fôro
authors.affiliation: Laboratório de Investigações Em Neurodegeneração e Infecção, Instituto de Ciências Biológicas, Universidade Federal do Pará, Hospital Universitário João de Barros Barreto, Rua dos Mundurucus 4487, Guamá, Belém, Pará, CEP 66073-000, Brazil.
authors.forename: Marcia Consentino Kronka
authors.initials: MC
authors.lastname: Sosthenes
authors.affiliation: Laboratório de Investigações Em Neurodegeneração e Infecção, Instituto de Ciências Biológicas, Universidade Federal do Pará, Hospital Universitário João de Barros Barreto, Rua dos Mundurucus 4487, Guamá, Belém, Pará, CEP 66073-000, Brazil.
authors.forename: João
authors.initials: J
authors.lastname: Bento-Torres
authors.affiliation: Departamento de Arbovirologia e Febres Hemorrágicas, Instituto Evandro Chagas, Ananindeua, Pará, Brazil.
authors.forename: Pedro Fernando
authors.initials: PF
authors.lastname: da Costa Vasconcelos
authors.affiliation: Laboratory of Experimental Neuropathology, Department of Pharmacology, University of Oxford, Oxford, England, UK.
authors.forename: Daniel Clive
authors.initials: DC
authors.lastname: Anthony
authors.affiliation: Laboratório de Investigações Em Neurodegeneração e Infecção, Instituto de Ciências Biológicas, Universidade Federal do Pará, Hospital Universitário João de Barros Barreto, Rua dos Mundurucus 4487, Guamá, Belém, Pará, CEP 66073-000, Brazil. cwpdiniz@gmail.com.|Laboratory of Experimental Neuropathology, Department of Pharmacology, University of Oxford, Oxford, England, UK. cwpdiniz@gmail.com.
authors.forename: Cristovam Wanderley Picanço
authors.initials: CW
authors.lastname: Diniz
mesh_terms: D000367:Age Factors; D000818:Animals; D001253:Astrocytes / Q000378:metabolism* / Q000473:pathology*; D003071:Cognition / Q000502:physiology; D018891:Dentate Gyrus / Q000166:cytology / Q000378:metabolism; D004777:Environment; D005260:Female; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism; D006624:Hippocampus / Q000166:cytology / Q000502:physiology; D008568:Memory / Q000502:physiology; D051379:Mice
chemical_list: D005904:Glial Fibrillary Acidic Protein
keywords: Aging; Astrocytes morphology; Dentate gyrus; Environment; Exercise; Memory