RESUMO
Variations in dietary fatty acid composition influence the biological behaviour of certain tumours. Diets enriched with oleic acid (18:1 n-9) seem to promote tumour progression on several lines due perhaps to the development of essential fatty acid deficiency (EFAD), whereas n-3 fatty acids have a protective effect. Since the role played by lipids on salivary gland tumorigenesis has not yet been studied, an experimental model is presented. BALB/c mice were fed on four different diets: control, corn oil, fish oil and olein groups. Salivary gland adenocarcinomas were chemically induced by using 9,10-dimethyl-1,2-benzanthracene. Animals were sacrificed at the 20th post-injection week and several tumour parameters were analysed. Linoleic acid showed no promoting activity. Tumour size was larger in the olein group than in fish oil fed mice, indicating that the oleic acid, linked to the induced EFAD condition, has a protumorigenic activity whereas n-3 polyunsaturated fatty acids appear to exert a protective effect.
Assuntos
Gorduras Insaturadas na Dieta/farmacologia , Ácidos Graxos Ômega-3/farmacologia , Neoplasias da Glândula Submandibular/etiologia , 9,10-Dimetil-1,2-benzantraceno/toxicidade , Adenocarcinoma/etiologia , Adenocarcinoma/metabolismo , Adenocarcinoma/patologia , Animais , Carcinógenos/toxicidade , Óleo de Milho/farmacologia , Gorduras Insaturadas na Dieta/toxicidade , Ácidos Graxos Essenciais/deficiência , Feminino , Óleos de Peixe/farmacologia , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Ácidos Oleicos/farmacologia , Ácidos Oleicos/toxicidade , Neoplasias da Glândula Submandibular/metabolismo , Neoplasias da Glândula Submandibular/patologiaRESUMO
BACKGROUND: The exposure of human skin to leaves and branches of litre (Lithraea caustica), a Chilean endemic tree, induces a severe contact dermatitis characterized by swelling and pruritus in susceptible individuals. The allergenic priniciple of litre is 3-pentadecyl (10-enyl) catechol (litreol), which is structurally similar to the allergens isolated from poison oak and poison ivy. All of them belong to a family of compounds named urushiols. As a proelectrophilic allergen, litreol must be intracellularly activated before modifying proteins of individuals exposed to it. As a result, self-peptides derived from litreol-modified intracellular proteins would be presented in the context of class I MHC molecules. We hypothesized that CD8+ T lymphocytes would play a major role during the effector phase of the immune response induced by those modified peptides. In order to test this hypothesis, we investigated the cellular immune response to litreol in Balb/cJ mice. The role of the different lymphocyte subpopulations in this response was assessed by immunodepleting mice of CD4+ or CD8+ T lymphocytes using specific monoclonal antibodies (mAbs). We report the observation that the contact dermatitis induced by litreol has two components: a primary response which does not require TCRalpha beta+ T cells, and a secondary response mediated mainly by CD8+ T cells and regulated by CD4+ T cells. Our results show that CD8+ lymphocytes play a central role as effectors of the secondary response to litreol. Furthermore, our data suggest that two functionally different CD4+ T subpopulations serve as regulators of the CD8+ T cell function: a CD4+ T helper population sensitive to a low dose of the depleting mAb, and CD4+ T suppressor population which is eliminated only with a high dose of depleting mAb.
Assuntos
Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD4-Positivos/fisiologia , Linfócitos T CD8-Positivos/imunologia , Catecóis/farmacologia , Dermatite de Contato/imunologia , Linfócitos T Reguladores/imunologia , Animais , Feminino , Imunização , Inflamação/imunologia , Depleção Linfocítica , Camundongos , Camundongos Endogâmicos BALB C , Camundongos SCID , Pele/efeitos dos fármacosRESUMO
The effect of dietary quercetin (Q) was evaluated in rats treated with nitrosomethylurea (NMU). Pancreatic nodules and focal acinar cell hyperplasias were observed in groups treated with NMU (87%) and Q-NMU (100%). Although rats with dysplastic foci (27%) were found in the NMU-treated group, Q-NMU treatment resulted in a significantly higher number of rats with dysplastic foci (73%). Furthermore, carcinomas in situ (12%) and one microcarcinoma (4%) were found in these animals. Mitosis was significantly increased and apoptosis was diminished in focal acinar cell hyperplasias of the Q-NMU group. Our present results support a promoting and progressing effect of quercetin in the NMU model of rat pancreatic carcinogenesis.
Assuntos
Carcinógenos/toxicidade , Metilnitrosoureia/toxicidade , Neoplasias Pancreáticas/induzido quimicamente , Lesões Pré-Cancerosas/induzido quimicamente , Quercetina/toxicidade , Animais , Peso Corporal , Cocarcinogênese , Feminino , Masculino , Tamanho do Órgão , Neoplasias Pancreáticas/patologia , Lesões Pré-Cancerosas/patologia , Gravidez , Ratos , Ratos WistarRESUMO
It is widely known that dietary lipids can modify the ability of different cancers to grow up and metastasize, especially mammary gland tumors. However, it is still unclear whether n-6 fatty acids behave as tumor promoters in this gland cell population. The effect of different nutritional polyunsaturated fatty acids (PUFAs) on tumor growth parameters of two transplantable murine mammary gland adenocarcinomas of low and high metastatic ability was tested on hosts fed diets with corn oil (CO) rich in 18:2n-6, evening primrose oil (EPO) containing 18:3n-6 (GLA) and a third formula supplemented with olein (O) 18:1n-9, which induces an essential fatty acid deficiency (EFAD). Tumor growth parameters were not adversely affected in the corn oil group with respect to stock-fed controls. Furthermore, metastatic spreading diminished in this group. EPO showed a moderate antitumor activity whereas the n-9-enriched diet showed no clear-cut effects. In both mammary gland tumors, n-6 fatty acid-rich lipids formulae, containing GLA and linoleic acid, were not tumor promoters. On the contrary, both exhibited anticancer activity.
Assuntos
Adenocarcinoma/secundário , Gorduras Insaturadas na Dieta/farmacologia , Ácidos Graxos Insaturados/farmacologia , Neoplasias Mamárias Animais/patologia , Adenocarcinoma/induzido quimicamente , Adenocarcinoma/tratamento farmacológico , Animais , Carcinógenos , Gorduras Insaturadas na Dieta/uso terapêutico , Ácidos Graxos Insaturados/uso terapêutico , Feminino , Masculino , Neoplasias Mamárias Animais/induzido quimicamente , Neoplasias Mamárias Animais/tratamento farmacológico , Camundongos , Camundongos Endogâmicos BALB C , Invasividade NeoplásicaRESUMO
Certain tumor growth parameters (GP) of two mesenchymal transplantable tumors maintained on C57BL/6J mice were characterized. Considering that many experimental, clinical and epidemiologic data have indicated that n-3 and n-6 essential fatty acids are nutrients which may delay the development as well as improve the course of cancer, GPs were evaluated on hosts fed on a semisynthetic formula containing 5% of corn oil (CO) or cod liver oil (CLO) and stock diet (C group). Although survival and latency time of tumor-bearing mice were shortened, other GP as percentage of successful implants were improved by both oils in sarcoma-bearing hosts, suggesting that n-3 and n-6 fatty acids might play a modulating role for the development of these tumors.