Effects of aging and short-term dietary restriction on neurogenesis and cellular senescence in the zebrafish (Danio Reio) brain

buir.advisorAdams, Michelle Marie
dc.contributor.authorErbaba, Begün
dc.date.accessioned2016-10-03T06:15:03Z
dc.date.available2016-10-03T06:15:03Z
dc.date.copyright2016-09
dc.date.issued2016-09
dc.date.submitted2016-09-30
dc.descriptionCataloged from PDF version of article.en_US
dc.descriptionThesis (M.S.): Bilkent University, Department of Neuroscience, İhsan Doğramacı Bilkent University, 2016.en_US
dc.descriptionIncludes bibliographical references (leaves 41-51).en_US
dc.description.abstractCurrently we know from rodent and fish studies that adult neuron generation is reduced but still continues in old animals with a dynamic change throughout aging. This process occurs mainly in hippocampal region, which is thought to be analogous to a region in telencephalon of the zebrafish brain. Changes in this neuron turnover are thought to be one contributing factor to cognitive change occuring with advanced age. Since we know that external factors can affect the process of neurogenesis, and as previous studies showed, dietary restriction (DR) extends life span; here, we hypothesized that DR should also alleviate several age associated alterations. In order to test this, we applied a 10-week feeding regimen to young (8-9 months) and old (26-32.5 months) male and female fish. We had two dietary regimen groups, one fed Ad libitum and one fed with a DR that was a pattern of every-other-day feeding, which is a widely accepted method of DR. A total of 124 animals were used in this study. As a result, a significant loss of body weight in both young and old DR groups was observed without an effect on body lengths. To be able to label actively dividing cells we used Bromodeoxyuridine (BrdU), which is a thymidine analog. It is injected into the fish intraperitoneally prior to euthanasia. Four hours later the brains were dissected and fixed for sectioning. We obtained cross-sectional slices of 50 m thickness with a vibratome, performed immunostaining with antibodies against BrdU, NeuN (neuronal marker), HuC (neuronal marker); and visualized the brain sections with confocal microscopy forming 3D reconstructed pictures. We counted the BrdU positive cells in all brain slices, forming a regional map of the telencephalic region of zebrafish brain, in which we documented the specific regions where the adult neurogenesis dominates the most and least. Our results confirmed that there are more BrdU positive cells in young animals than olds, and that age is correlated with an increased senescence associated fi-galactosidase (SA-fi-gal) activity, along with shortened telomere lengths. The 10-week diet was not found to be creating a significant change in cell proliferation rates, cellular senescence, or the differentiation pattern of glial cells. However, it was demonstrated to have a shortening effect on telomere lengths. Our data suggest that the potential effects of DR could be related to telomere regulation. Therefore, in order to detect differentially expressed genes that could be related to this mechanism between the groups, we performed microarray analysis with differing DR regimens. Initial data indicated no significant effects of a 4-week diet on gene expression differences among aged fish. Further analysis of the different periods of DR will be performed. Taken together, the effects of age are more robust than a short-term DR.en_US
dc.description.provenanceSubmitted by Betül Özen (ozen@bilkent.edu.tr) on 2016-10-03T06:15:02Z No. of bitstreams: 1 10126363.pdf: 2185653 bytes, checksum: 28174fbf6739a47b5900aab04853ef95 (MD5)en
dc.description.provenanceMade available in DSpace on 2016-10-03T06:15:03Z (GMT). No. of bitstreams: 1 10126363.pdf: 2185653 bytes, checksum: 28174fbf6739a47b5900aab04853ef95 (MD5) Previous issue date: 2016-09en
dc.description.statementofresponsibilityby Begün Erbaba.en_US
dc.format.extentxi, 51 leaves : illustrations, graphics.en_US
dc.identifier.itemidB154170
dc.identifier.urihttp://hdl.handle.net/11693/32381
dc.language.isoEnglishen_US
dc.rightsinfo:eu-repo/semantics/openAccessen_US
dc.subjectNeurogenesisen_US
dc.subjectAgingen_US
dc.subjectDietary restrictionen_US
dc.subjectZebrafishen_US
dc.subjectBrainen_US
dc.subjectCell proliferationen_US
dc.subjectMicroarrayen_US
dc.subjectTelomereen_US
dc.subjectCellular senescenceen_US
dc.titleEffects of aging and short-term dietary restriction on neurogenesis and cellular senescence in the zebrafish (Danio Reio) brainen_US
dc.title.alternativeYaşlanma ve kısa dönem kalori kısıtlamasının zebra balığı (Danio Reio) beyninde nörogenez ve hücresel yaşlanma üzerindeki etkilerien_US
dc.typeThesisen_US
thesis.degree.disciplineNeuroscience
thesis.degree.grantorBilkent University
thesis.degree.levelMaster's
thesis.degree.nameMS (Master of Science)

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