Orientador: Solange Maria de Almeida / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-04T04:01:35Z (GMT). No. of bitstreams: 1 Pontual_MariaLuizadosAnjos_D.pdf: 19820473 bytes, checksum: dbd5a33178ca3a999b3af5968d746de7 (MD5) Previous issue date: 2005 / Resumo: Avaliou-se o efeito radioprotetor do selenito de sódio nas células secretoras das glândulas submandibulares de ratos, por meio da análise ultraestrutural. Foram utilizados 57 ratos subdivididos em quatro grupos experimentais: controle, irradiado, selenito de sódio e selenito de sódio/irradiado. Os animais, pertencentes aos grupos irradiado e selenito de sódio/irradiado, foram submetidos a 15 Gy de radiação gama na região de cabeça e pescoço. Nos animais correspondentes aos grupos selenito de sódio e selenito de sódio/irradiado foi administrado 0,5 mg/kg de peso de selenito de sódio por via intraperitonial 24 horas antes da irradiação e nos grupos controle e irradiado, injetou-se solução salina. As glândulas submandibulares foram removidas após 4, 8, 12, 24, 48 e 72 horas da irradiação. Os resultados mostraram que a radiação causou danos, desde o primeiro tempo, nas células secretoras, sendo maior para as células serosas. Os danos intensificaram-se até o período de 12 horas, com início do processo de reparo no tempo de 24 horas, sem recuperação completa nos últimos tempos avaliados. O grupo selenito de sódio também apresentou alterações celulares nos tempos estudados, porém com menor dano em relação ao causado pela radiação. Foram observados vacuolização, lise de inclusões citoplasmáticas e alterações nucleares. O grupo selenito de sódio/irradiado apresentou maior semelhança com o grupo controle que os outros grupos tratados durante todos os tempos estudados. Foi concluído que, apesar das alterações observadas no grupo selenito de sódio, o selenito de sódio possui ação radioprotetora nas células secretoras das glândulas submandibulares / Abstract: The radioprotective effect of sodium selenite in the secretory cells of submandibular glands of rats was assessed by ultrastructural analysis. A total of 57 rats were used, which were divided into four experimental groups: control, irradiated, sodium selenite and sodium selenite/irradiated. The animals belonging to the irradiated and sodium selenite /irradiated groups were submitted to 15 Gy of gamma radiation at the head and neck. The animals in the sodium selenite and sodium selenite/irradiated groups received intraperitoneal injections of sodium selenite, 0.5mg/kg of body weight, at 24 hours before irradiation; the control and irradiated groups received injection of saline solution. The submandibular glands were removed at 4, 8, 12, 24, 48 and 72 hours after irradiation. The results demonstrated that the radiation induced damages to the secretory cells, especially the serous cells, since the first period. The damages were increased up to the 12- hour period, with onset of the repair process at 24 hours, without complete recovery at the last periods. The sodium selenite group also presented cellular alterations in the study periods, yet with less damage compared to that caused by radiation. There was vacuolization, lysis of cytoplasmic inclusions and nuclear alterations. The sodium selenite/irradiated group was more similar to the control group than the other groups treated at all study periods. It was concluded that, despite the alterations observed in the sodium selenite group, the sodium selenite has a radioprotective action on the secretory cells of submandibular glands / Doutorado / Radiologia Odontologica / Doutor em Radiologia Odontológica

Speichelglykane können einerseits spezifisch an bakterielle Lektine binden und damit deren Adhäsion an orale Oberflächen vermitteln, andererseits eine Antiadhäsion bedingen. Sie stellen ein Schutzsystem für orale Oberflächen dar. Bei vorhandener Karies bzw. Parodontitis ist die Konzentration bestimmter Glykokonjugate verändert. Ziel dieser Studie war es, die Reaktivität der Glandulae majores bzgl. ihrer Sekretion von Glykanen in Abhängigkeit einer experimentellen Gingivitis zu ermitteln. 14 gesunde Probanden enthielten sich 9 Tage der Mundhygiene. Neben der Erhebung des PBI und QH wurde drüsenspezifisch Speichel gewonnen. Die Konzentrationen an die Lektine PNA, GS1, VVA, SNA und AAA bindender Komponenten und deren drüsenspezifische Sekretionsraten wurden bestimmt. Bei allen Probanden stiegen PBI und QH im Versuchsverlauf signifikant an. Gleiches galt für die Speichelmenge nach Stimulation sowie zum Ende der Kontrollreihe. Die Konzentrationen der verschiedenen Glykane verhielten sich unabhängig von der Speichelmenge und unabhängig voneinander. Meist ergab sich eine erhöhte Glykansekretion spezifisch für das untersuchte Lektin. Neben dem Konzentrationsgefälle der einzelnen Drüsen war auch eine Verschiebung nach erfolgter Stimulation zu beobachten. Da genetische und externe Einflüsse für diese Studie weitgehend ausgeschlossen werden konnten bzw. als konstant einzuordnen waren, darf die Veränderung als Reaktion auf die orale Bakterienbelastung angesehen werden. Der Rückgang bestimmter terminaler Strukturen könnte als Folge der vermehrten Synthese anderer, in Bezug auf die veränderte Bakterienflora effektiverer Speichelbestandteile eingeordnet werden. Basierend auf dem Modell, dass freie Glykane die Adhäsion von Mikroorganismen inhibieren können, ließe sich die gemessene Reaktion der Speicheldrüsensekretion als ein gesteigerter Schutzmechanismus im Sinne einer ´first line of defence´ interpretieren. Dieser könnte z.B. in Bezug auf Prophylaxe und Therapie genutzt werden. / Salivary glycans can bind specificly to bacterial lectins. Consequently, bacterial adhesion to oral surfaces is mediated or inhibited by glycans. It is known that the concentration of certain glycans changes in the presence of caries or periodontitis. Therefore this study examines the reactivity of the major salivary glands with respect to the secretion of glycans as conditioned by an experimentally induced gingivitis. 14 healthy subjects refrained from all oral hygiene measures for 9 days. On 5 days a plaque and bleeding index as well as pure glandula saliva with and without stimulation were obtained. The collected salivary samples were examined for their concentration of certain structures that bind to the lectins ´PNA´, ´GS1´, ´VVA´, ´SNA´ and ´AAA´. All subjects developed a gingivitis as measured by the plaque and bleeding index. Salivary flow increased after stimulation and compared to baseline at the end of the trial. The concentration of glycans was neither related to one of the glands nor to the salivary flow. Besides to the differentials of concentration after stimulation there was no symmetrical development between the concentrations of salivary lectin-specific components compared one lectin to another. Genetic and external influences could be largely excluded or considered to be stable during the trial. Therefore the observed results can be regarded as a reaction to the increased bacterial load. The decrease of certain terminal structures in saliva might be explained by a raised synthesis of other components, which are more effective in defending the body against bacterial adhesion. The observed changes in salivary secretion might be interpreted as a mechanism in order to protect the human organism within the meaning of a ´first line of defence´. This mechanism would be able to respond more quickly than the immune system and might be used in future, for example, for preventive and therapeutical strategies.