51 |
Olfactory identification decline: a preclinical biomarker for Alzheimer's DiseaseKnight, Jamie 12 June 2017 (has links)
The earliest stage of Alzheimer’s disease (AD) pathology begins in one of the main components of the olfactory pathway, the entorhinal cortex, making deficits in smell a potential prospective biomarker for the early detection of AD. This study contributes to the field with a reproduction and extension of work by Wilson, Arnold, Schneider, Boyle, Buchman, and Bennett (2009). A sample of 1089 individuals (M=78.4 years), more than double the data available in 2009, completed annual assessments of olfactory functioning, and cognitive functioning for up to 18 years with brain donation at death. Mixed effects models conditioned on demographics estimated between and within-person effects in olfactory functioning and episodic memory (EM). After successful reproduction of Wilson et al. (2009), addition of AD pathology (ADP) demonstrated that both ADP and olfaction were significantly related to EM at baseline. Higher ADP at autopsy was significantly related to faster declines in olfaction, as well as more rapid declines in EM. Higher olfactory scores were associated with higher EM scores and a model for EM with olfaction as time-varying covariate indicated that at a given occasion, individuals with higher olfactory scores also have higher EM scores.
These results align with the hypotheses that difficulty in identifying odors predicts development of cognitive impairment; increased levels of AD pathology are related to both decreased EM at baseline and faster declines, as well as faster rates of decline in olfaction; and olfaction and cognition are travelling together over time. / Graduate / 2018-06-01 / 0766 / 0633 / jknight@uvic.ca
|
52 |
Dévelopement d'une méthode bio-informatique pour la prédiction des régions amyloidogéniques dans les protéines. / Development of bioinformatics method for prediction of amyloidogenic regions in proteins.Ahmed, Abdullah 02 July 2013 (has links)
La formation d'agrégats protéiques insolubles et fibreux, appelés fibrilles amyloïdes, est impliquée dans une large variété de maladies humaines. Parmi elles, figurent entre autres, le diabète de type II, l'arthrite rhumatoïde et, notamment, les atteintes neurodégénératives débilitantes, telles que les maladies d'Alzheimer, de Parkinson ou encore de Huntington. Actuellement, il n'existe ni traitement, ni diagnostic précoce pour aucune de ces maladies.De nombreuses études ont montré que la capacité à former des fibrilles amyloïdes est une propriété inhérente à la chaîne polypeptidique. Ce constat a conduit au développement d'un certain nombre d'approches computationnelles permettant de prédire les propriétés amyloïdogéniques à partir de séquences d'amino-acides. Si ces méthodes s'avèrent très performantes vis à vis de courts peptides (~ 6 résidus), leur application à des séquences plus longues correspondant aux peptides et protéines en lien avec les maladies, engendre un nombre trop élevé de faux positifs. Le principal objectif de cette thèse consiste à développer une meilleure approche bioinformatique, capable de prédire les régions amyloïdogéniques à partir d'une séquence protéique. Récemment, l'utilisation de nouvelles techniques expérimentales a permis de mieux appréhender la structure des amyloïdes. Il est ainsi apparu que l'élément caractéristique de la majorité des fibrilles amyloïdes impliquées dans les maladies, était constitué d'une structure étagée (β-arcade), résultant de l'empilement de motifs « feuillet β – coude – feuillet b » appelés « β-arches ». Nous avons mis à profit cette particularité structurale pour créer une approche bioinformatique permettant de prédire les régions amyloïdogéniques d'une protéine à partir de l'information contenue dans sa séquence. Les résultats provenant de l'analyse des structures de type β-arcade, connues et modélisées, ont été compilés et traités à l'aide d'un algorithme écrit en langage Java, afin de créer le programme ArchCandy.L'application de ce programme à une sélection de séquences protéiques et peptidiques, connues pour leur lien avec les maladies, a permis de démontrer qu'il était en mesure de prédire correctement la majorité de ces séquences, de même que les séquences mutées impliquées dans les maladies familiales. Outre la prédiction de régions à haut potentiel amyloïde, ce programme suggère la conformation structurale adoptée par les fibrilles amyloïdes. Le séquençage de génomes entiers devenant toujours plus abordable, notre méthode offre une perspective de détermination individuelle des profils à risque, vis à vis de maladies neurodégénératives, liées à l'âge ou autres. Elle s'inscrit ainsi pleinement dans l'ère de la médecine personnalisée. / A broad range of human diseases are linked to the formation of insoluble, fibrous, protein aggregates called amyloid fibrils. They include, but are not limited to, type II diabetes, rheumatoid arthritis, and perhaps most importantly, debilitating neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease, and Huntington's disease. There currently exists no cure, and no means of early diagnosis for any of these diseases. Numerous studies have shown that the ability to form amyloid fibrils is an inherent property of the polypeptide chain. This has lead to the development of a number of computational approaches to predict amyloidogenicity by amino acid sequences. Although these methods perform well against short peptides (about 6 residues), they generate an unsatisfactory high number of false positives when tested against longer sequences of the disease-related peptides and proteins. The main objective of this thesis was to develop an improved bioinformatics based approach to predict amyloidogenic regions from protein sequence.Recently new experimental techniques have shed light on the structure of amyloids showing that the core element of a majority of disease-related amyloid fibrils is a columnar structure (β—arcade) produced by stacking of β-strand-loop-β-strand motifs called “β-arches”. Using this structural insight, we have created a bioinformatics based approach to predict amyloidogenic regions from protein sequence information. Data from the analysis of the known and modeled β-arcade structures was incorporated into a rule based algorithm implemented in the Java programming language to create the ArchCandy program. Testing it against a set of protein and peptide sequences known to be related to diseases has shown that it correctly predicts most of these sequences and a number of mutated sequences related to the familial diseases. In addition to the prediction of regions with high amyloidogenic potential, a structural arrangement of the amyloid fibril is also suggested for each prediction. As whole genome sequencing becomes cheaper, our method provides opportunity to create individual risk profiles for the neurodegenerative, age-related and other diseases ushering in an era of personalized medicine.
|
53 |
Aggregation Inhibition and Detection of Alzheimer’s Amyloidogenic and Oligomeric PeptidesUnknown Date (has links)
Protein aggregation, oligomer and fibril formation is one of the dominant
characteristics in the pathogenesis of a number of neurodegenerative diseases, such as
Alzheimer’s disease (AD). Inhibition of toxic oligomer and fibril formation is one of
the approaches to find potential drug candidates for AD. Additionally, early diagnosis
of these amyloid species can provide mechanistic understanding of protein aggregation
and thus can pave the way for preventing the onset of AD. The aim of this dissertation
was 1) to explore the effects of charged cholesterol derivatives on the aggregation
kinetic behavior of Amyloid-β40 (Aβ40), 2) to probe Aβ40 oligomer and amyloid
formation in vitro using gold nanoparticles (AuNPs), and 3) to monitor the kinetic
effect of various natural product molecules on Aβ40 aggregation in vitro. In the first
chapter, a general introduction about AD as an amyloidogenic disease, amyloid cascade
hypothesis, and the manipulation of Aβ peptides aggregation kinetics using different
approaches was presented. In the second chapter, we studied the effects of oppositely charged cholesterol derivatives on the aggregation kinetics of Aβ. In the third chapter,
we developed a gold nanoparticles (AuNPs) assay to probe Aβ40 oligomers and
amyloid formation. In chapter IV, we monitored the effects of various small molecules
on the aggregation kinetics of Aβ40. In chapter V, we discussed the methods and
experimental details. / Includes bibliography. / Dissertation (Ph.D.)--Florida Atlantic University, 2018. / FAU Electronic Theses and Dissertations Collection
|
54 |
Investigating the role of FXN antisense transcript 1 in Friedreich ataxiaMikaeili, Hajar January 2017 (has links)
Friedreich ataxia (FRDA) is a neurodegenerative disorder that is inherited in an autosomal recessive pattern. The most common FRDA mutation is hyperexpansion of a GAA triplet repeat sequence in the first intron of the affected gene, frataxin (FXN), resulting in decreased frataxin protein expression. The hyperexpanded GAA repeats can adopt unusual DNA structures and induce aberrant epigenetic changes leading to heterochromatin mediated gene silencing. Several epigenetic changes, including increased levels of DNA methylation, histone modifications, repressive chromatin formation and elevated levels of non-coding RNA have been reported in FRDA. It has been reported that a novel FXN antisense transcript (FAST-1), is present at higher levels in FRDA patient-derived fibroblasts and its overexpression is associated with the depletion of CTCF, a chromatin insulator protein, and heterochromatin formation involving the critical +1 nucleosome. Previously, characteristics of FAST-1 were investigated in our lab and a full-length FAST-1 transcript containing a poly (A) tail was identified. To investigate any possible effects of FAST-1 on FXN expression, I first overexpressed this FAST-1 transcript in three different non-FRDA cell lines and a consistent decrease of FXN expression was observed in each cell type compared to control cells. I also identified that FAST-1 copy number is positively correlated with increased FAST-1 expression, which in turn is negatively correlated with FXN expression in FAST-1 overexpressing cells. Additionally, we found that FAST-1 overexpression is associated with increased levels of DNA methylation at CpG sites U6 and U11 of the FXN upstream GAA repeat region, together with CTCF depletion and heterochromatin formation at the 5'UTR of the FXN gene. To further investigate the role of FAST-1 in FXN gene silencing, I used a small hairpin RNA (shRNA) strategy to knock down FAST-1 expression in FRDA fibroblast cells. I found that knocking down FAST-1 increases FXN expression, but not to the level of control cells. Lastly, I investigated the pattern of FAST-1 expression and histone modifications at the FXN transgene in our new FRDA mouse model, designated YG8LR. The YG8LR mice showed decreased levels of FXN expression and H3K9ac and increased levels of FAST-1 expression and H3K9me3. Our data suggest that since FAST-1 is associated with FXN gene silencing, inhibition of FAST-1 may be an approach for FRDA therapy.
|
55 |
The role of polyglutamine oligomer in pathogenesis of polyglutamine diseases.January 2010 (has links)
Wu, Chi Chung. / "September 2010." / Thesis (M.Phil.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references (leaves 86-96). / Abstracts in English and Chinese. / Abstract --- p.i / Abstract (Chinese version) --- p.iii / Acknowledgments --- p.iv / List of Abbreviations --- p.v / List of Tables --- p.vii / List of Figures --- p.viii / Chapter 1. --- INTRODUCTION / Chapter 1.1. --- Neurodegenerative disorders 一 a brief overview --- p.1 / Chapter 1.2. --- Polyglutamine diseases --- p.1 / Chapter 1.3. --- Polyglutamine protein conformers and toxicity --- p.5 / Chapter 1.4. --- in vivo modeling of polyglutamine diseases in Drosophila / Chapter 1.4.1. --- GAL4/UAS transgene expression system in Drosophila --- p.13 / Chapter 1.4.2. --- Temporal control of transgene expression systemin Drosophila --- p.15 / Chapter 1.4.3. --- Drosophila as a model to study polyglutamine diseases --- p.16 / Chapter 1.5. --- in vitro polyglutamine diseases models --- p.19 / Chapter 1.6. --- Aim of study --- p.23 / Chapter 2. --- MATERIALS AND METHODS / Chapter 2.1. --- Drosophila culture and manipulation / Chapter 2.1.1. --- Drosophila culture --- p.25 / Chapter 2.1.2. --- Pseudopupil assay of adult retinal degeneration --- p.25 / Chapter 2.2. --- Sodium Dodecyl Sulfate-Polyacrylamide Gel Electrophoresis (SDS-PAGE) / Chapter 2.2.1. --- Protein extraction from adult Drosophila heads --- p.26 / Chapter 2.2.2. --- Preparation of SDS-polyacrylamide gel and electrophoresis --- p.27 / Chapter 2.2.3. --- Western blotting --- p.28 / Chapter 2.2.4. --- Immunodetection --- p.29 / Chapter 2.3. --- Solubilization of SDS-insoluble protein --- p.31 / Chapter 2.4. --- Filter retardation assay --- p.31 / Chapter 2.5. --- Immunoprecipitation --- p.32 / Chapter 2.6. --- Nucleocytoplasmic fractionation --- p.33 / Chapter 2.7. --- PCR cloning / Chapter 2.7.1 . --- Drosophila DNA preparation --- p.34 / Chapter 2.7.2. --- Construction of pGEX4T3-MJDflQ27/81 expression plasmid --- p.34 / Chapter 2.8. --- in vitro aggregation assay / Chapter 2.8.1. --- Expression and purification of GST-MJDAQ27/81 protein --- p.36 / Chapter 2.8.2. --- in vitro aggregation --- p.37 / Chapter 2.8.3. --- Native slot-blot --- p.38 / Chapter 2.9. --- Reagents and buffers / Chapter 2.9.1. --- Reagents for Drosophila culture --- p.39 / Chapter 2.9.2. --- Reagents for SDS-PAGE --- p.39 / Chapter 2.9.3. --- Reagents for filter retardation assay --- p.42 / Chapter 2.9.4. --- Reagents for immunoprecipitation --- p.43 / Chapter 2.9.5. --- Reagents for nucleocytoplasmic fractionation --- p.43 / Chapter 2.9.6. --- Reagents for PCR cloning --- p.44 / Chapter 2.9.7. --- Reagents for in vitro aggregation assay --- p.46 / Chapter 3. --- Establishment of a GAL80ts-mediated transgenic Drosophila model of Machado-Joseph Disease (MJD) / Chapter 3.1. --- Introduction --- p.48 / Chapter 3.2. --- Results / Chapter 3.2.1. --- GAL80ts-mediated expression of expanded full-length MJD protein caused progressive neuronal degenerationin Drosophila --- p.49 / Chapter 3.2.2. --- Detection of SDS-insoluble expanded full-length MJD protein and its correlation with neuronal degeneration / Chapter 3.2.2.1. --- Progressive neuronal degeneration is not mediated by progressive accumulation of expanded full-length MJD protein --- p.51 / Chapter 3.2.2.2. --- SDS-soluble expanded full-length MJD protein does not correlate with progressive neuronal degeneration --- p.53 / Chapter 3.2.2.3. --- Progressive accumulation of SDS-insoluble expanded full-length MJD protein correlate with progressive neuronal degeneration --- p.55 / Chapter 3.3. --- Discussion --- p.57 / Chapter 4. --- Detection of conformational changes of expanded full-length MJD protein and its association with neuronal degeneration / Chapter 4.1. --- Introduction --- p.60 / Chapter 4.2. --- Results / Chapter 4.2.1. --- Expanded full-length MJD protein underwent conformational changes from monomer to fibrils and such conformational changes correlated with neuronal degeneration --- p.61 / Chapter 4.2.2. --- Mechanistic studies of how conformational changes of expanded full-length MJD protein triggers neuronal degeneration / Chapter 4.2.2.1. --- Expanded full-length MJD protein gradually accumulated in the nucleus during the course of neurodegeneration --- p.62 / Chapter 4.2.2.2. --- Fibrillar expanded full-length MJD protein caused transcriptional dysregulation of endogenous Hsp70 gene --- p.66 / Chapter 4.2.3. --- Consolidation of the role of fibrillar expanded full-length MJD protein in neuronal degeneration --- p.67 / Chapter 4.3. --- Discussion --- p.72 / Chapter 5. --- Attempts to generate new conformation-specific antibody against recombinant expanded full-length MJD proteins / Chapter 5.1. --- Introduction --- p.75 / Chapter 5.2. --- Results / Chapter 5.2.1. --- Recombinant expanded full-length MJD protein underwent conformational changes during in vitro aggregation --- p.75 / Chapter 5.3. --- Discussion --- p.77 / Chapter 6. --- GENERAL DISCUSSION --- p.81 / Chapter 7. --- CONCLUSION --- p.84 / Chapter 8. --- REFERENCES --- p.86
|
56 |
Analyzing the effects of Ca<sup>2+</sup> dynamics on mitochondrial function in health and diseaseToglia, Patrick 04 April 2018 (has links)
Mitochondria plays a crucial role in cells by maintaining energy metabolism and directing cell death mechanisms by buffering calcium (Ca2+ )from cytosol. Therefore, the Ca2+ overload of mitochondria due to the upregulated cytosolic Ca2+ , observed in many neurological disorders is hypothesized to be a key pathway leading to mitochondrial dysfunction and cell death. In particular, Ca2+ homeostasis disruptions due to Alzheimer’ s disease (AD)-causing presenilins (PS1/PS2) and oligomeric forms of β-amyloid peptides Aβ commonly found in AD patients are presumed to cause detrimental effects on the mitochondria and its ability to function properly. We begin by showing that Familial Alzheimer’s disease (FAD)-causing PS mutants affect intracellular Ca2+ ([Ca2+]i) homeostasis by enhancing the gating of inositol 1,4,5-trisphosphate (IP3) receptor (IP3R) Ca2+ channels on the endoplasmic reticulum (ER), leading to exaggerated Ca2+ release into the cytoplasm. Using experimental IP3R-mediated Ca2+ release data in conjunction with a computational model of mitochondrial bioenergetics, we explore how the differences in mitochondrial Ca2+ uptake in control cells and cells expressing FAD-causing PS mutants affect key variables such as ATP, reactive oxygen species (ROS), NADH, and mitochondrial Ca2+ ([Ca2+ ]m). We find that as a result of exaggerated [Ca2+]i in FAD-causing mutant PS-expressing cells, the rate of oxygen consumption increases dramatically and overcomes the Ca2+ dependent enzymes that stimulate NADH production. This leads to decreased rates of proton pumping due to diminished membrane potential (Ψm) along with less ATP and enhanced ROS production. These results show that through Ca2+ signaling disruption, mutant PS leads to mitochondrial dysfunction and potentially cell death.
Next, the model for the mitochondria is expanded to include the mitochondrial uniporter (MCU) that senses Ca2+ in the microdomain formed by the close proximity of mitochondria and ER. Ca2+ concentration in the microdomain ([Ca2+] mic) depends on the distance between the cluster of IP3R channels (r) on ER and mitochondria, the number of IP3R in the cluster (nIP3R), and open-probability (Po) of IP3R. Using the same experimental results for Ca2+ release though IP3R due to FAD-causing PS mutants, in conjunction with a computational model of mitochondrial bioenergetics, a data-driven Markov chain model for IP3R gating, and a model for the dynamics of the mitochondrial permeability transition pore (PTP), we explore the difference in mitochondrial Ca2+ uptake in cells expressing wild type (PS1-WT) and FAD-causing mutant (PS1-M146L) PS. We find that increased mitochondrial [Ca2+]m due to the gain-of-function enhancement of IP3R channels in the cell expressing PS1-M146L leads to the opening of PTP in high conductance state (PTPh), where the latency of opening is inversely correlated with r and proportional to nIP3R. Furthermore, we observe diminished inner mitochondrial Ψm, [NADH], [Ca2+]m, and [ATP] when PTP opens. Additionally, we explore how parameters such as the pH gradient, inorganic phosphate concentration, and the rate of the Na+/ Ca2+ -exchanger affect the latency of PTP to open in PTPh.
Intracellular accumulation of oligomeric forms of Aβ are now believed to play a key role in the early phase of AD as their rise correlates well with the early symptoms of the disease. Extensive evidence points to impaired neuronal Ca2+ homeostasis as a direct consequence of the intracellular Aβ oligomers. To study the effect of intracellular Aβ on Ca2+ signaling and the resulting mitochondrial dysfunction, we employed data-driven modeling in conjunction with total internal reflection fluorescence (TIRF) microscopy (TIRFM). High resolution fluorescence TIRFM together with detailed computational modeling provides a powerful approach towards the understanding of a wide range of Ca2+ signals mediated by the IP3R. Achieving this requires a close agreement between Ca2+ signals from computational models and TIRFM experiments. However, we found that elementary Ca2+ release events, puffs, imaged through TIRFM do not show the rapid single-channel opening and closing during x and between puffs using data-driven single channel models. TIRFM also shows a rapid equilibration of 10 ms after a channel opens or closes which is not achievable in simulation using standard Ca2+ diffusion coefficients and reaction rates between indicator dye and Ca2+. Using the widely used Ca2+ diffusion coefficients and reaction rates, our simulations show equilibration rates that are eight times slower than TIRFM imaging. We show that to get equilibrium rates consistent with observed values, the diffusion coefficients and reaction rates have to be significantly higher than the values reported in the literature. Once a close agreement between experiment and model is achieved, we use multiscale modeling in conjunction with patch-clamp electrophysiology of IP3R and fluorescence imaging of whole-cell Ca2+ response, induced by intracellular Aβ42 oligomers to show that Aβ42 inflicts cytotoxicity by impairing mitochondrial function. Driven by patch-clamp experiments, we first model the kinetics of IP3R, which is then extended to build a model for the whole-cell Ca2+ signals. The whole-cell model is then fitted to fluorescence signals to quantify the overall Ca2+ release from the ER by intracellular Aβ42 oligomers through G-protein-mediated stimulation of IP3 production. The estimated IP3 concentration as a function of intracellular Aβ42 content together with the whole-cell model allows us to show that Aβ42 oligomers impair mitochondrial function through pathological Ca2+ uptake and the resulting reduced mitochondrial inner membrane potential, leading to an overall lower ATP and increased production of reactive oxygen species and [H2O2]. We further show that mitochondrial function can be restored by the addition of Ca2+ buffer EGTA, in accordance with the observed abrogation of Aβ42 cytotoxicity by EGTA in our live cells experiments.
Finally, our modeling study was extended to other pathological phenomena such as epileptic seizures and spreading depolarizations (SD) and their effects on mitochondria by incorporating conservation of particles and charge, and accounting for the energy required to restore ionic gradients to the neuron. By examining the dynamics as a function of potassium and oxygen we can account for a wide range of neuronal hyperactivity from seizures, normoxic SD, and hypoxic SD (HSD) in the model. Together with a detailed model of mitochondria xi and Ca2+ -release through the ER, we determine mitochondrial dysfunction and potential recovery mechanisms from HSD. Our results demonstrate that HSD causes detrimental mitochondrial dysfunction that can only be recovered by restoration of oxygen. Once oxygen is replenished to the neuron, organic phosphate and pH gradients along the mitochondria determine how rapid the neuron recovers from HSD.
|
57 |
The effects of treadmill training in hemi-parkinsonian ratsPoulton, Nadine P 30 August 2004
The purpose of this study was to investigate whether locomotor training, in the form of treadmill training, could ameliorate neurochemical changes and behavioural deficits in the 6-hydroxydopamine (6-OHDA) rat model of Parkinsons disease. It has been recently demonstrated that rehabilitative forelimb motor training can attenuate dopamine loss and some deficits in forelimb movements in this animal model. In addition, brief locomotor treadmill training has been shown to attenuate forelimb deficits in 6-OHDA treated rats. However, it is not known whether locomotor training could result in an amelioration of locomotor deficits in these animals. Rats were lesioned with 6-OHDA injected intracerebrally. Lesioned rats were randomly assigned to one of 3 groups: early treadmill trained, late treadmill trained and untrained. Animals in the treadmill groups were trained to trot on a moving treadmill for 2 x 20 minute sessions daily for 30 days, beginning either 24 hours or 7 days after 6-OHDA injection. Untrained animals were exposed to a stationary treadmill for the same time periods. All animals were assessed on their abilities to perform several behavioural tasks designed to test locomotor and forelimb movement abilities prior to 6-OHDA injection and again at 3 and 6 weeks post-injection. These tests included measurement of ground reaction forces during overground locomotion, paw placements during a ladder crossing task, forelimb useage during exploratory behaviour and ability to initiate forelimb stepping movements. In addition, assessments of dopamine depletion in the striatum were carried out first in vivo, by measuring apomorphine-induced rotations at 2 weeks post 6-OHDA injection, and subsequently by post-mortem analysis of dopamine levels in the striatum using HPLC at the conclusion of the study. Treadmill training resulted in attenuation of dopamine depletion compared to non-treadmill trained animals, as measured by both apomorphine injection and HPLC. However, treadmill training produced no difference in behavioural deficits on a variety of tests compared to untrained animals. In some cases, early treadmill trained animals tended to display more severe behavioural deficits compared to untrained animals. Late treadmill training had a similar but smaller effect compared to early treadmill training. We conclude that treadmill training does not ameliorate locomotor deficits, in the 6-OHDA model of Parkinsons disease, even though this same training results in attenuation of dopamine loss in the striatum.
|
58 |
The effects of treadmill training in hemi-parkinsonian ratsPoulton, Nadine P 30 August 2004 (has links)
The purpose of this study was to investigate whether locomotor training, in the form of treadmill training, could ameliorate neurochemical changes and behavioural deficits in the 6-hydroxydopamine (6-OHDA) rat model of Parkinsons disease. It has been recently demonstrated that rehabilitative forelimb motor training can attenuate dopamine loss and some deficits in forelimb movements in this animal model. In addition, brief locomotor treadmill training has been shown to attenuate forelimb deficits in 6-OHDA treated rats. However, it is not known whether locomotor training could result in an amelioration of locomotor deficits in these animals. Rats were lesioned with 6-OHDA injected intracerebrally. Lesioned rats were randomly assigned to one of 3 groups: early treadmill trained, late treadmill trained and untrained. Animals in the treadmill groups were trained to trot on a moving treadmill for 2 x 20 minute sessions daily for 30 days, beginning either 24 hours or 7 days after 6-OHDA injection. Untrained animals were exposed to a stationary treadmill for the same time periods. All animals were assessed on their abilities to perform several behavioural tasks designed to test locomotor and forelimb movement abilities prior to 6-OHDA injection and again at 3 and 6 weeks post-injection. These tests included measurement of ground reaction forces during overground locomotion, paw placements during a ladder crossing task, forelimb useage during exploratory behaviour and ability to initiate forelimb stepping movements. In addition, assessments of dopamine depletion in the striatum were carried out first in vivo, by measuring apomorphine-induced rotations at 2 weeks post 6-OHDA injection, and subsequently by post-mortem analysis of dopamine levels in the striatum using HPLC at the conclusion of the study. Treadmill training resulted in attenuation of dopamine depletion compared to non-treadmill trained animals, as measured by both apomorphine injection and HPLC. However, treadmill training produced no difference in behavioural deficits on a variety of tests compared to untrained animals. In some cases, early treadmill trained animals tended to display more severe behavioural deficits compared to untrained animals. Late treadmill training had a similar but smaller effect compared to early treadmill training. We conclude that treadmill training does not ameliorate locomotor deficits, in the 6-OHDA model of Parkinsons disease, even though this same training results in attenuation of dopamine loss in the striatum.
|
59 |
Proteomic strategies for analysis of cerebrospinal fluid in neurodegenerative disorders /Hansson, Sara, January 2008 (has links)
Diss. (sammanfattning) Göteborg : Göteborgs universitet, 2008. / Härtill 5 uppsatser.
|
60 |
Mitochondrial dysfunction in neurodegeneration /Ekstrand, Mats, January 2005 (has links)
Diss. (sammanfattning) Stockholm : Karol. inst., 2005. / Härtill 4 uppsatser.
|
Page generated in 0.0649 seconds