Standardized environmental enrichment supports enhanced brain plasticity in healthy rats and prevents cognitive impairment in epileptic rats.
Environmental enrichment of laboratory animals influences brain plasticity, stimulates neurogenesis, increases neurotrophic factor expression, and protects against the effects of brain insult. However, these positive effects are not constantly observed, probably because standardized procedures of environmental enrichment are lacking. Therefore, we engineered an enriched cage (the Marlau™ cage), which offers: (1) minimally stressful social interactions; (2) increased voluntary exercise; (3) multiple entertaining activities; (4) cognitive stimulation (maze exploration), and (5) novelty (maze configuration changed three times a week). The maze, which separates food pellet and water bottle compartments, guarantees cognitive stimulation for all animals. Compared to rats raised in groups in conventional cages, rats housed in Marlau™ cages exhibited increased cortical thickness, hippocampal neurogenesis and hippocampal levels of transcripts encoding various genes involved in tissue plasticity and remodeling. In addition, rats housed in Marlau™ cages exhibited better performances in learning and memory, decreased anxiety-associated behaviors, and better recovery of basal plasma corticosterone level after acute restraint stress. Marlau™ cages also insure inter-experiment reproducibility in spatial learning and brain gene expression assays. Finally, housing rats in Marlau™ cages after severe status epilepticus at weaning prevents the cognitive impairment observed in rats subjected to the same insult and then housed in conventional cages. By providing a standardized enriched environment for rodents during housing, the Marlau™ cage should facilitate the uniformity of environmental enrichment across laboratories.
Université de Lyon, Lyon, France.
Raafat P
RP
Fares
Amor
A
Belmeguenai
Pascal E
PE
Sanchez
Hayet Y
HY
Kouchi
Jacques
J
Bodennec
Anne
A
Morales
Béatrice
B
Georges
Chantal
C
Bonnet
Sandrine
S
Bouvard
Robert S
RS
Sloviter
Laurent
L
Bezin
D000223:Adaptation, Psychological / Q000502:physiology; D000818:Animals; D001007:Anxiety / Q000150:complications; D001835:Body Weight; D001921:Brain / Q000166:cytology / Q000473:pathology / Q000502:physiology* / Q000503:physiopathology*; D056547:CA1 Region, Hippocampal / Q000166:cytology / Q000473:pathology / Q000502:physiology / Q000503:physiopathology; D003071:Cognition; D004435:Eating; D005106:Exploratory Behavior / Q000502:physiology; D006262:Health; D006799:Housing, Animal / Q000592:standards*; D050356:Lipid Metabolism; D008297:Male; D055495:Neurogenesis / Q000235:genetics; D009473:Neuronal Plasticity; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D012015:Reference Standards; D015203:Reproducibility of Results; D012149:Restraint, Physical / Q000523:psychology; D013226:Status Epilepticus / Q000473:pathology* / Q000503:physiopathology* / Q000523:psychology; D013315:Stress, Psychological / Q000150:complications / Q000473:pathology / Q000503:physiopathology; D013569:Synapses / Q000473:pathology
D012333:RNA, Messenger