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Previous issue date: 2015-03-25 / Head and neck radiotherapy often involves major salivary glands and causes morphologic and functional alterations, resulting in hyposalivation and xerostomia. Literature was reviewed in the first manuscript, addressing the structural changes observed in the salivary glands resulting from oxidative stress caused by radiotherapy and pathogenic mechanisms involved. Preventive and regenerative therapies for altered acinar morphology and glandular function were also discussed. Among the acute and late microscopic alterations observed in glandular tissue, there are particularly changes indicative of cell death, hypovascularization, formation of fibrous tissue and edema. Considering the evidences before mentioned, the aim of this study was to evaluate the effect of low level laser therapy (LLLT) on radiotherapy-induced morphological changes and immunodetection of caspase-3 protein in parotids of mice. Forty-one Swiss mice were divided into a control group and three experimental groups: radiotherapy, 2 J laser and 4 J laser. The experimental groups were exposed to ionizing radiation in a single session of 10 Gy. In the laser groups, a GaAlAs laser (830 nm, 100 mW, 0.028 cm2, 3.57 W/cm2) was used on the region corresponding to the parotid glands, with 2 J energy (20 sec, 71 J/cm2) or 4 J (40 sec, 135 J/cm2) per point. The animals were euthanized 48 hours or seven days after radiotherapy and parotid glands were dissected for morphological analysis and immunodetection of caspase-3. There was no significant difference between groups in the immunodetection of caspase-3, but the laser groups had a lower percentage compared to the radiotherapy group. Furthermore, the results indicated that LLLT promoted the preservation of acinar structure, reduced the occurrence of cytoplasmic vacuolation and stimulated parotid gland vascularization. Of the two LLLT protocols, the one using 4 J of energy showed better results. Given the methodological limitations of this study, further researches should be conducted in irradiated animals, using different LLLT protocols and observing glandular response, not only in the short term but also long term, when the occurrence of late changes in the salivary glands can be analyzed. / A radioterapia direcionada ? regi?o de cabe?a e pesco?o frequentemente envolve as gl?ndulas salivares maiores, as quais sofrem altera??es morfol?gicas e funcionais, resultando em hipossaliva??o e xerostomia. No primeiro artigo desta disserta??o foi realizada uma revis?o da literatura com o objetivo de abordar as altera??es estruturais observadas nas gl?ndulas salivares e os poss?veis mecanismos patog?nicos pelos quais o estresse oxidativo, decorrente da radioterapia, causa disfun??es salivares. Al?m disso, foram revisados os m?todos de preven??o e regenera??o da morfologia acinar e da fun??o glandular. Entre as altera??es microsc?picas agudas e tardias observadas no tecido glandular irradiado, podem-se citar altera??es indicativas de morte celular como a apoptose, hipovasculariza??o, forma??o de tecido fibroso e edema. Considerando as evid?ncias anteriormente mencionadas, o objetivo deste estudo foi avaliar, em gl?ndulas par?tidas de camundongos, o efeito da terapia laser de baixa pot?ncia (TLBP) sobre altera??es morfol?gicas causadas pela radioterapia e na imunodetec??o da prote?na caspase-3. Quarenta e um camundongos Swiss foram distribu?dos em um grupo controle e tr?s grupos experimentais: radioterapia, laser 2 J e laser 4 J. Os grupos experimentais foram submetidos ? radia??o ionizante em sess?o ?nica de 10 Gy. Nos grupos laser, um laser de diodo, GaAlAs (830 nm, 100 mW, 0,028 cm2, 3,57 W/cm2) foi utilizado de forma pontual sobre a regi?o correspondente ?s gl?ndulas par?tidas, com energia de 2 J (20 seg, 71 J/cm2) ou 4 J (40 seg, 135 J/cm2) por ponto. Os animais foram eutanasiados 48 h ou sete dias ap?s a radioterapia e as gl?ndulas par?tidas dissecadas para an?lise morfol?gica e imunodetec??o da caspase-3. N?o houve diferen?a significativa entre os grupos na imunodetec??o da caspase-3, entretanto, os grupos laser apresentaram percentuais inferiores aos do grupo radioterapia. Al?m disso, os resultados indicaram que a TLBP promoveu preserva??o da estrutura acinar, reduziu a ocorr?ncia de vacuoliza??o citoplasm?tica e estimulou a vasculariza??o glandular. Entre os protocolos de TLBP, o que utilizou a energia de 4 J apresentou os melhores resultados. Tendo em vista as limita??es metodol?gicas desta pesquisa, mais estudos devem ser conduzidos em animais irradiados, utilizando diferentes protocolos de TLPB e observando a resposta glandular, n?o apenas em curto prazo, como tamb?m em longo prazo, quando a ocorr?ncia de altera??es tardias nas gl?ndulas salivares pode ser analisada.
| Identifer | oai:union.ndltd.org:IBICT/oai:tede2.pucrs.br:tede/6042 |
| Date | 25 March 2015 |
| Creators | Acauan, Monique Dossena |
| Contributors | Salum, Fernanda Gon?alves, Gomes, Ana Paula Neutzling |
| Publisher | Pontif?cia Universidade Cat?lica do Rio Grande do Sul, Programa de P?s-Gradua??o em Odontologia, PUCRS, Brasil, Faculdade de Odontologia |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/masterThesis |
| Format | application/pdf |
| Source | reponame:Biblioteca Digital de Teses e Dissertações da PUC_RS, instname:Pontifícia Universidade Católica do Rio Grande do Sul, instacron:PUC_RS |
| Rights | info:eu-repo/semantics/openAccess |
| Relation | -8096554818733665164, 600, 600, 600, 4673435736271820140, -2070498469879244349 |
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