published_or_final_version / Dentistry / Master / Master of Dental Surgery

Please read the abstract in the section 00front of this document / Thesis (DSc (Oral Pathology))--University of Pretoria, 2005. / Community Dentistry / unrestricted

Sjogren's Syndrome (SS) is characterized by lymphocytic infiltration, destruction and dysfunction of the lacrimal and salivary glands and the presence of serum autoantibodies. Although, approximately 0.5% of the population suffers from SS, there is a female predominance of 9:1 compared with males. Most women with SS are postmenopausal; however, not all women who are post-menopausal develop SS. Therefore, we postulate that a decrease in the circulating levels of hormones creates an environment favorable to the development of SS in a predisposed genetic background. In order to carry out our studies, we used the NOD.B10.H2b mouse model of SS, and ovariectomized (OVX) them as a model for the post-menopausal condition. We removed the lacrimal glands and measured the gene expression and protein levels of several cytokines and chemokines known to be upregulated in patients with SS such as : lL-1B, IL-10, INF-y, TNFa, CCL9 and CXCL13. / We also stained for markers of B cells (B220+) and T cells (CD4+ and CD8+), and counted positively stained cleaved caspase-3 cells as an indication of apoptosis. These experiments were done 3, 7 and 21 days post-OVX and compared to sham operated animals. In order to determine whether the changes observed with OVX were triggered mainly by a genetic pre-disposition, a non-prediposed OVX and sham operated mouse (C57BL/10) was used as control. We found that gene expression of IL-1B, IL-10 and IF-y were upregulated in the lacrimal glands of the OVX NOD.B10.H2b mice at 3 days post-OVX compared with sham operated animals. Gene expression of IL-1B, IL-10, IFN-y, TNF-a, CCL9 and CXCL13, and protein levels of IL-1B, IL-10 and CCL9 were upregulated in the OVX NOD.B10.H2b mice at 7 days post-OVX compared to sham operated animals. / Also, at 7 days, an increase in B220+ B cells and an increase in cleaved caspase-3 were also observed in the OVX NOD.B10.H2b mice lacrimal glands compared to sham operated animals. At 21 days, protein levels of IL-10 were also highly upregulated in the OVX NOD.B10.H2b mice, together with an increase of B220+ B cells, a slight increase in the CD4/CD8 ratio and an increase on the number of caspase-3 positive cells. No changes were observed in any of the above parameters measured in the OVX C57BL/10 mice compared to the sham operated group, supporting our hypothesis that both, genetics and a decrease in the levels of hormones are necessary for SS to occur. / by Vanessa Seamon. / Thesis (Ph.D.)--Florida Atlantic University, 2009. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2009. Mode of access: World Wide Web.

Please read the abstract in the section 00front of this document / Thesis (DSc (Oral Pathology))--University of Pretoria, 2005. / Community Dentistry / unrestricted

Le syndrome de Sjögren (SS) est une maladie auto-immunitaire caractérisée par une infiltration lymphocytaire des glandes exocrines menant le plus souvent, à une xérophtalmie et à une xérostomie. La physiopathologie de la maladie est complexe et malgré les progrès realisés, il existe beaucoup de questions à repondre. Classiquement, le syndrome sec qui caractérise la maladie résulterait d’un double processus où dans un premier temps, la glande serait envahie par des cellules lymphoplasmocytaires puis secondairement détruite. Des avancées récentes dans la physiopathologie de la maladie ont démontré le rôle de nouvelles molécules, Aquaporine 5 (AQP5) et anticorps muscariniques, qui peuvent contribuer au syndrome sec. Dans ce travail, nous avons étudié des marqueurs diagnostiques de la maladie. Nous avons montré que 2 alarmines, HMGB1 et S100A8/A9 sont augmentés mais ne présentent pas de corrélation avec le score d’activité de la maladie. Utilisant différents modèles animaux de SS, nous avons montré une modification de la distribution de l’AQP5. De plus, nous avons montré que la modification de la distribution de l’AQP5 dans les glandes salivaires était liée à la présence des infiltrats inflammatoires. Utilisant un modèle non-immun de souris qui présente un syndrome sec, l’expression de l’AQP5 n’était pas modifiée en l’absence d’infiltrats inflammatoires. Ces résultats montrent que la modification de l’AQP5 dans le SS est liée à la présence des infiltrats inflammatoires. / Doctorat en Sciences médicales / info:eu-repo/semantics/nonPublished