Brain Phenotype of Car9-/- Knock-out Mouse
AUTIO, SALLA (2008)
2008
Biokemia - Biochemistry
Lääketieteellinen tiedekunta - Faculty of Medicine
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Hyväksymispäivämäärä
2008-06-18
Julkaisun pysyvä osoite on
https://urn.fi/urn:nbn:fi:uta-1-18991
https://urn.fi/urn:nbn:fi:uta-1-18991
Tiivistelmä
Background and aims: Carbonic anhydrase IX (CA IX) is a membrane-bound isozyme, which shows only low expression in the normal human brain. Previously Car9-/- knock-out mice have been stated to be aggressive and hyperactive and their brain tissues showed vacuolar changes. Our aim was to study Car9-/- knock-out mice brain phenotype using behavioural tests, morphological analysis and microarray.
Methods: The behavioural analysis for the Car9-/- knock-out mice was done with a slightly modified SHIRPA protocol using wild-type mice as controls. Duration of the behavioural analysis was 12 months and the mice were tested every two months. The brain tissue samples were obtained from the mice sacrificed at each time point after the behavioural tests. The brain tissue samples were stained with Haematoxylin-Eosin (HE) –staining and electron microscopy was performed to detect cellular changes in brain. Gene expression in the brain of Car9-/- knock-out mice was studied with a cDNA microarray analysis.
Results: The behavioural tests showed that Car9-/- knock-out mice were more active in their response tested for locomotor activity, transfer arousal and spontaneous activity. Morris water maze test showed that Car9-/- knock-out mice had difficulties to learn and they had also poorer visual memory. Haematoxylin-Eosin –staining and electron microscopy revealed vacuolar changes in the brain samples obtained from Car9-/- knock-out mice. Electron microscopy showed also myelin and neuron degeneration, empty axons/dentrites and cell decomposition in brain tissue. Microarray showed 12 down-regulated and 11 up-regulated genes with a fold –change over 1.40 and under -1.40. Several genes were down-regulated in chromosome 4, which is also the location of Car9 gene.
Conclusions: We have identified a mouse strain, which has alterations in behaviour and brain tissue. The Car9-/- knock-out mice had degenerative changes in their brain tissue. According to the behavioural tests the Car9-/- knock-out mice were more active and showed abnormal memory functions. Because several genes were down-regulated in the close proximity of Car9-/- gene further investigations are warranted to find out if our findings are related to CA IX deficiency.
Methods: The behavioural analysis for the Car9-/- knock-out mice was done with a slightly modified SHIRPA protocol using wild-type mice as controls. Duration of the behavioural analysis was 12 months and the mice were tested every two months. The brain tissue samples were obtained from the mice sacrificed at each time point after the behavioural tests. The brain tissue samples were stained with Haematoxylin-Eosin (HE) –staining and electron microscopy was performed to detect cellular changes in brain. Gene expression in the brain of Car9-/- knock-out mice was studied with a cDNA microarray analysis.
Results: The behavioural tests showed that Car9-/- knock-out mice were more active in their response tested for locomotor activity, transfer arousal and spontaneous activity. Morris water maze test showed that Car9-/- knock-out mice had difficulties to learn and they had also poorer visual memory. Haematoxylin-Eosin –staining and electron microscopy revealed vacuolar changes in the brain samples obtained from Car9-/- knock-out mice. Electron microscopy showed also myelin and neuron degeneration, empty axons/dentrites and cell decomposition in brain tissue. Microarray showed 12 down-regulated and 11 up-regulated genes with a fold –change over 1.40 and under -1.40. Several genes were down-regulated in chromosome 4, which is also the location of Car9 gene.
Conclusions: We have identified a mouse strain, which has alterations in behaviour and brain tissue. The Car9-/- knock-out mice had degenerative changes in their brain tissue. According to the behavioural tests the Car9-/- knock-out mice were more active and showed abnormal memory functions. Because several genes were down-regulated in the close proximity of Car9-/- gene further investigations are warranted to find out if our findings are related to CA IX deficiency.