RESUMO
An important rat model using the chemical carcinogen 4-nitroquinoline-1-oxide (4NQO) has been described for the study of the process of oral carcinogenesis. This model replicates the gradual progression seen in oral carcinoma patients. However, due to its high level of toxicity, its use in fundamental research is challenging. Here, we propose a secure and efficient modified protocol based on a lower dose of 4NQO concentration as well as an increased water supply and hypercaloric diet, in order to reduce the damage caused to the animals during the process of oral carcinogenesis. Twenty-two male Wistar rats were exposed to 4NQO, evaluated clinically once a week and euthanized at 12 and 20 weeks for histopathological analysis. The protocol involves a staggered dose of 4NQO up to a concentration of 25 ppm, associated with two days of pure water, a 5% glucose solution once a week and a hypercaloric diet. This modified protocol prevents the immediate consequences of the carcinogen. At week 7, all animals displayed clinically evident tongue lesions. From a histological perspective, after 12 weeks of 4NQO exposure, 72.7% of the animals developed epithelial dysplasia and 27.3% developed in situ carcinoma. In the group exposed for 20 weeks, epithelial dysplasia and in situ carcinoma were diagnosed in one case each, whereas invasive carcinoma was diagnosed in 81.8% of the cases. Nonsignificant modification of animal's behavior and weight was observed. This new proposed 4NQO protocol was secure and effective for studying oral carcinogenesis and can be used to conduct lengthy investigations.
Assuntos
Carcinoma , Neoplasias da Língua , Camundongos , Ratos , Masculino , Animais , 4-Nitroquinolina-1-Óxido/toxicidade , Ratos Wistar , Neoplasias da Língua/induzido quimicamente , Neoplasias da Língua/patologia , Carcinogênese/induzido quimicamente , Carcinogênese/patologia , Carcinógenos/toxicidadeRESUMO
Our aim was to verify the modulative TP-4-ol capacity in 4-nitroquinoline-1-oxide induced oral rat cancer. The stereoisomers of TP-4-ol were used against the human tongue squamous cell line and the negative stereoisomer showed lower IC50. Thirty-one Holtzman rats (120-130 g) were cancer-induced by 4-nitroquinoline-1-oxide (4-NQO/8 weeks/25 ppm) and 32 Holtzman rats (120-130 g) were used to healthy and TP-4-ol toxicity experiments. Six groups were used, healthy, 0.1nL/g of TP-4-ol, 8nL/g of TP-4-ol, 4-NQO, 4-NQO + 0.1nL/g of TP-4-ol, and 4-NQO + 8nL/g of TP-4-ol. We performed the toxicity analysis by biochemical and histopathological analysis. The biochemistry analysis includes alkaline phosphatase (ALP), alanine aminotransferase (ALT), aspartate transaminase (AST), urea, and creatinine and the histopathology analysis includes the liver, kidney, lung, and spleen. Specifically, for malign modulation, we performed a macroscopic and microscopic analysis. The group exposed to 0.1nL/g of TP-4-ol demonstrated a reduced risk of malignancy in dysplasia considering the criteria of architecture and cytology. Similarly, a drop of percentual rats with SCC diagnosis was observed in 4-NQO + 0.1nL/g (41.6%) when compared to 4-NQO (87.5%). Moreover, the 4-NQO group presented a median of 2.62 SCC/rat and the 4-NQO + 0.1nL/g demonstrated a median of 0.75 SCC/rat. For toxicity analysis, 4-NQO + 0.1nL/g showed focal necrosis in the kidney and 4-NQO showed lung hemorrhagic areas. The concentration of 0.1nL/g was more effective in reducing the tongue induction of potentially malignant and malignant lesions by 4-NQO. A kidney toxicity was observed in healthy animals exposed to 0.1nL/g of TP-4-ol. The negative isoform of terpinen-4-ol negatively modulates the development of potentially malignant and malignant lesions in rats (Rattus nonverdicts albinos, Holtzman) exposed to 4-NQO. (-)-Terpinen-4-ol reduced the mice percentual with squamous cell carcinoma, 87.5 to 41.6%, and decreased the cancer/rat ratio of 2.62 in 4-NQO to 0.75 in 4-NQO + 0.1nL/g. This represents 52.4% by group and 71.3% in the cancer/rat ratio.
Assuntos
Lesões Pré-Cancerosas , Terpenos , Neoplasias da Língua , 4-Nitroquinolina-1-Óxido/toxicidade , Alanina Transaminase , Fosfatase Alcalina , Animais , Aspartato Aminotransferases , Creatinina , Humanos , Lesões Pré-Cancerosas/induzido quimicamente , Lesões Pré-Cancerosas/patologia , Ratos , Ratos Sprague-Dawley , Terpenos/farmacologia , Língua/patologia , Neoplasias da Língua/induzido quimicamente , Neoplasias da Língua/patologia , Ureia/farmacologiaRESUMO
The aim of this study was to evaluate the chemopreventive potential of purple carrot extract following rat tongue carcinogenesis induced by 4-nitroquinoline 1-oxide (4NQO). For this purpose, histopathological analysis, proliferative status, antioxidant activity and inflammatory status were investigated in this setting. A total of 20 male rats were distributed into four groups as follows (n = 5 per group): Group 1-free access to water and commercial diet for 12 weeks; Group 2-received 4NQO at 50 ppm dose in drinking water daily and commercial diet for 12 weeks; Group 3-free access to water and received diet supplemented with purple carrot extract (0.1 g/kg) for 12 weeks; and Group 4-received 4NQO at 50 ppm dose in drinking water daily and diet supplemented with purple carrot extract (0.1 g/kg) for 12 weeks. Histopathological analysis revealed that animals treated with purple carrot extract reduced the oral lesions such as dysplasia and squamous cell carcinoma. Animals with oral pre-neoplastic lesions and treated with purple carrot extract decreased ki-67 and 8-OHdG immunoexpression. Moreover, pNFκBp50 and MyD88 protein expressions were decreased after purple carrot treatment associated or not with 4NQO exposure. SOD-Mn mRNA levels increased with treatment with purple carrot extract as well. In conclusion, our results demonstrated that purple carrot extract was able to protect oral lesions induced by 4NQO in Wistar rats as a result of antioxidant activity, anti-inflammatory potential and antiproliferative and antimutagenic actions.
Assuntos
Daucus carota/química , Extratos Vegetais/farmacologia , Neoplasias da Língua/prevenção & controle , 4-Nitroquinolina-1-Óxido , Animais , Carcinógenos , Proliferação de Células/efeitos dos fármacos , Masculino , Extratos Vegetais/análise , Polifenóis/análise , Polifenóis/farmacologia , Ratos , Ratos Wistar , Neoplasias da Língua/induzido quimicamente , Neoplasias da Língua/patologiaRESUMO
Evidence show that stress hormones can influence cancer progression, but its role in carcinogenesis is poorly understood. In this study, we used a new method based on oral carcinogenesis model in rats to test the hypothesis that physiological levels of stress hormones in the normal tissue microenvironment would have significant predictive value for chemically induced cancer occurrence. Male Wistar rats were submitted to a tongue biopsy for measuring not-stress induced levels of norepinephrine, corticosterone, adrenocorticotropic hormone (ACTH) and brain-derived neurotrophic factor (BDNF) in the tissue before carcinogenic induction. Rats were treated with the 4-nitroquinoline-1-oxide (4NQO) chemical carcinogen for twenty weeks and then euthanized for microscopic evaluation of the tongue lesions. Increased pre-carcinogen norepinephrine concentrations and reduced basal corticosterone levels in the normal tissue microenvironment were predictive for oral squamous cell carcinoma (OSCC) occurrence. Likewise, increased pre-carcinogen norepinephrine levels in the normal microenvironment were associated a lower expression of pCDKN2a-p16 in OSCCs. Post-carcinogen levels of corticosterone and BDNF in oral leukoplakia tissues (precursor lesion of OSCC) and post-carcinogen corticosterone concentrations in OSCCs were higher than basal levels in the normal mucosa. Increased norepinephrine concentrations in OSCCs were associated to a greater tumor volume and thickness. Furthermore, higher levels of norepinephrine, ACTH and BDNF in OSCCs were associated to a lesser intensity of the lymphoplasmocytic infiltrate. This study shows that pre-carcinogen stress hormones levels in the normal microenvironment may be predictive for chemically induced cancer in rats. Moreover, chemical carcinogenesis can promote stressor-like effects with hormonal changes in the tissue microenvironment, which may be associated to tumor progression.
Assuntos
Hormônios/metabolismo , Neoplasias da Língua/metabolismo , Língua/metabolismo , 4-Nitroquinolina-1-Óxido/farmacologia , Hormônio Adrenocorticotrópico , Animais , Biomarcadores Tumorais , Fator Neurotrófico Derivado do Encéfalo , Carcinogênese/metabolismo , Carcinógenos , Microambiente Celular/fisiologia , Corticosterona , Modelos Animais de Doenças , Masculino , Neoplasias/induzido quimicamente , Neoplasias/metabolismo , Norepinefrina , Ratos , Ratos Wistar , Fatores de Risco , Neoplasias da Língua/induzido quimicamenteRESUMO
Acute inflammatory response after photodynamic therapy is frequently described, and increase on mast cell degranulation is also present during this process. The mast cell activation may improve angiogenesis, and this fact has been associated with progression of oral premalignant lesions (OPL). The aim of this study was to evaluate whether photodynamic therapy (PDT) increases mast cell density (MCD) and microvessels density (MVD) in 4-nitroquinoline-1-oxide(4NQO)-induced OPL in rats. 4NQO-induced OPL were treated or not with 5-ALA followed by laser irradiation (PDT group and 4NQO groups, respectively). Mast cells and CD34+ microvessels were counted. Both PDT and 4NQO groups had MCD and MVD that were higher than normal mucosa (p b 0.05). The 4NQO group had the lowest number of non-degranulated MCD in comparison to experimental periods of PDT (PDT 6 h p=0.020; 24 h p=0.016; 48 h p=0.003; 72 h p=0.033). Only in the PDT group did MCD and MVD have a significant correlation (r= 0.6219, p = 0.010). 5-ALA-mediated PDT modified the MCD and MVD in the induced OPL, leading to degranulation of mast cells and angiogenesis. A PDT protocol with an efficient eradication of the OPL must be adopted considering the angiogenesis potential associated with the mast cell activation after the therapy.
Assuntos
Ácido Aminolevulínico/uso terapêutico , Mastócitos/fisiologia , Microvasos/patologia , Fármacos Fotossensibilizantes/uso terapêutico , Neoplasias da Língua/tratamento farmacológico , 4-Nitroquinolina-1-Óxido/toxicidade , Ácido Aminolevulínico/farmacologia , Animais , Antígenos CD34/metabolismo , Degranulação Celular/efeitos dos fármacos , Degranulação Celular/efeitos da radiação , Feminino , Hiperplasia/induzido quimicamente , Hiperplasia/patologia , Lasers , Mastócitos/citologia , Mucosa Bucal/efeitos dos fármacos , Mucosa Bucal/patologia , Neovascularização Fisiológica/efeitos dos fármacos , Neovascularização Fisiológica/efeitos da radiação , Fotoquimioterapia , Fármacos Fotossensibilizantes/farmacologia , Ratos , Ratos Wistar , Língua/patologia , Neoplasias da Língua/induzido quimicamente , Neoplasias da Língua/veterináriaRESUMO
BACKGROUND: Squamous cell carcinoma (SSC) of the head and neck is the sixth most common cancer and is rarely diagnosed in early stages. The transcription factor KrÏppel-like factor 4 (Klf4) suppresses cell proliferation and promotes differentiation. Inducible mice carrying an oral-specific ablation of Klf4 (K14-CreER(tam) /Klf4(flox/flox) ) develop mild dysplastic lesions and abnormal differentiation in the tongue. Aiming to analyze whether Klf4 cooperate in oral chemical carcinogenesis,we applied 4-nitroquinoline 1-oxide (4NQO), a tobacco surrogate, to this conditional Klf4 knockout mice. METHODS: K14-CreER(tam) /Klf4(flox/flox) and control mice were treated with 4NQO for 16 weeks and monitored until week 30. Histopathological samples were used for diagnostic purposes and immunofluorescence detection of epithelial differentiation markers. RESULTS: 4NQO-treated K14-CreER(tam) /Klf4(flox/flox) mice (Klf4KO 4NQO) showed a significant weight loss and developed more severe dysplastic lesions than control mice with 4NQO (P < 0.005). The Klf4KO 4NQO showed a tendency to higher incidence of oral SCC and a marked keratinization pattern in dysplasias, in situ carcinomas and SCC. Also, tongues derived from Klf4KO 4NQO mice exhibited reduced terminal differentiation as judged by cytokeratin 1 staining when compared with 4NQO-treated controls. CONCLUSIONS: Klf4 ablation results in more severe dysplastic lesions in oral mucosa, with a tendency to higher incidence of SCC, after chemical carcinogenesis. We show here, in a context similar to the human carcinogenesis, that absence of Klf4 accelerates carcinogenesis and correlates with the absence of cytokeratin 1 expression. These results suggest a potential role for KLF4 as a tumor suppressor gene for the tongue epithelium.
Assuntos
Carcinogênese/induzido quimicamente , Carcinoma de Células Escamosas/patologia , Neoplasias de Cabeça e Pescoço/patologia , Fatores de Transcrição Kruppel-Like/antagonistas & inibidores , Neoplasias Bucais/patologia , 4-Nitroquinolina-1-Óxido , Animais , Carcinogênese/metabolismo , Carcinogênese/patologia , Carcinógenos , Carcinoma de Células Escamosas/induzido quimicamente , Carcinoma de Células Escamosas/genética , Carcinoma de Células Escamosas/metabolismo , Diferenciação Celular/efeitos dos fármacos , Modelos Animais de Doenças , Expressão Gênica , Neoplasias de Cabeça e Pescoço/induzido quimicamente , Neoplasias de Cabeça e Pescoço/genética , Neoplasias de Cabeça e Pescoço/metabolismo , Queratinas/metabolismo , Fator 4 Semelhante a Kruppel , Fatores de Transcrição Kruppel-Like/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Mucosa Bucal/efeitos dos fármacos , Mucosa Bucal/patologia , Neoplasias Bucais/induzido quimicamente , Neoplasias Bucais/genética , Neoplasias Bucais/metabolismo , Lesões Pré-Cancerosas/induzido quimicamente , Lesões Pré-Cancerosas/patologia , Carcinoma de Células Escamosas de Cabeça e Pescoço , Neoplasias da Língua/induzido quimicamente , Neoplasias da Língua/patologiaRESUMO
PURPOSE: The aim of this study was to evaluate whether sleep restriction (SR) could affect the mechanisms and pathways' essentials for cancer cells in tongue cancer induced by 4-nitroquinoline 1-oxide in Wistar rats. METHODS: The animals were distributed into 4 groups of 5 animals each treated with 50 ppm 4 NQO solution through their drinking water for 4 and 12 weeks. The animals were submitted to sleep restriction for 21 days using the modified multiple platform method, which consisted of placing 5 rats in a cage (41 × 34 × 16 cm) containing 10 circular platforms (3.5 cm in diameter) with water 1 cm below the upper surface. The investigations were conducted using immunohistochemistry of p53, Bax and Bcl-2 proteins related to apoptosis and its pathways. RESULTS: Although no histopathologic abnormalities were induced in the epithelium after 4 weeks of carcinogen exposure in all groups, in 12 weeks were observed pre-neoplastic lesions. Data analysis revealed statistically significant differences (P < 0.05) in 4 weeks group for p53, and for bcl-2. Following 12 weeks of 4NQO administration, we found significant differences between SR and control groups in p53, bax, and bcl-2 immunoexpression. CONCLUSION: Our results reveal that sleep restriction exerted alterations in proteins associated with proliferation and apoptosis in carcinogenesis.
Assuntos
Proteínas Reguladoras de Apoptose/análise , Carcinogênese , Proteínas Proto-Oncogênicas c-bcl-2/análise , Sono/fisiologia , Neoplasias da Língua/induzido quimicamente , Proteína Supressora de Tumor p53/análise , Proteína X Associada a bcl-2/análise , 4-Nitroquinolina-1-Óxido/efeitos adversos , Animais , Apoptose/efeitos dos fármacos , Carcinogênese/efeitos dos fármacos , Carcinógenos , Proliferação de Células/efeitos dos fármacos , Epitélio/química , Epitélio/efeitos dos fármacos , Leucoplasia Oral/induzido quimicamente , Leucoplasia Oral/química , Masculino , Lesões Pré-Cancerosas/induzido quimicamente , Lesões Pré-Cancerosas/química , Quinolonas/efeitos adversos , Distribuição Aleatória , Ratos , Ratos Wistar , Transtornos do Sono-Vigília/metabolismo , Fatores de Tempo , Neoplasias da Língua/químicaRESUMO
BACKGROUND: Most studies have demonstrated 4-NQO toxicity to oral epithelium during oral carcinogenesis induction, but systemic toxicity has been poorly addressed. The aim of this study was to describe the systemic effect of 4-NQO topical application during early phases of oral cancer induction. METHODS: A 4-NQO propylene glycol ointment was topically applied on the rat tongue three times a week for 16 weeks. Local and systemic 4-NQO toxicity was evaluated by body weight gain, hematology, and serum chemistry analyses, histopathology, and proliferating cell nuclear antigen (PCNA) immunohistochemistry. RESULTS: Significant reduction in body weight gain and in white blood cell count as well as significant increase in serum ALT and AST was observed after 16 weeks of 4-NQO topical application. Focal hepatic lobular necrosis, renal tubular degeneration, and decreased cellularity in the splenic white pulp were also detected. CONCLUSIONS: 4-NQO topical application on the tongue of rats for 16 weeks seems to have caused hepatic, renal, and splenic toxicity. Potential systemic toxicity should be considered to monitor for variables that could interfere in topical oral carcinogenesis experiments.
Assuntos
Carcinogênese/induzido quimicamente , Carcinógenos/toxicidade , Quinolonas/toxicidade , 4-Nitroquinolina-1-Óxido/toxicidade , Administração Tópica , Alanina Transaminase/sangue , Alanina Transaminase/efeitos dos fármacos , Animais , Aspartato Aminotransferases/sangue , Aspartato Aminotransferases/efeitos dos fármacos , Análise Química do Sangue , Feminino , Queratinócitos/efeitos dos fármacos , Túbulos Renais/efeitos dos fármacos , Contagem de Leucócitos , Leucoplasia Oral/induzido quimicamente , Fígado/efeitos dos fármacos , Monócitos/efeitos dos fármacos , Pâncreas/efeitos dos fármacos , Lesões Pré-Cancerosas/induzido quimicamente , Antígeno Nuclear de Célula em Proliferação/efeitos dos fármacos , Ratos , Ratos Wistar , Albumina Sérica/efeitos dos fármacos , Baço/citologia , Baço/efeitos dos fármacos , Glândula Submandibular/efeitos dos fármacos , Língua/efeitos dos fármacos , Neoplasias da Língua/induzido quimicamente , Aumento de Peso/efeitos dos fármacosRESUMO
AIMS: Tumor-associated tissue eosinophilia (TATE) has been correlated with prognosis in oral squamous cell carcinoma (OSCC). This study aimed to investigate whether eosinophils depletion affects experimental oral carcinogenesis. METHODS AND RESULTS: BALB/c (wild type - WT) and eosinophil-deficient (Δdb/GATA-1) mice were treated with the carcinogen 4-nitroquinoline-1-oxide (4NQO) in drinking water for 28 weeks. Tongues were collected for histopathological and immunohistochemical analysis, as well as for the evaluation of cytokines/chemokines by ELISA. The tongue SCC induced by 4NQO was associated with a rise in eosinophil numbers. WT-treated group showed a significantly increased incidence of SCC, with higher cytological atypia, in comparison with Δdb/GATA-1 mice. Consistently, the proliferative index was higher in WT compared to the Δdb/GATA-1-treated group. No significant changes in the concentration of CCL3, CCL11 and TNF-α were detected for both groups after 4NQO treatment. CONCLUSIONS: These results suggest that eosinophils might be responsible for the deleterious outcome of experimental tongue carcinogenesis, given that their ablation protects mice from OSCC.
Assuntos
Carcinoma de Células Escamosas/patologia , Eosinófilos/patologia , Neoplasias da Língua/patologia , 4-Nitroquinolina-1-Óxido/toxicidade , Animais , Carcinógenos/toxicidade , Carcinoma de Células Escamosas/induzido quimicamente , Modelos Animais de Doenças , Ensaio de Imunoadsorção Enzimática , Imuno-Histoquímica , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Mutantes , Neoplasias da Língua/induzido quimicamenteRESUMO
The experimental oral carcinogenesis induced by the chemical 4-nitroquinoline 1-oxide (4NQO) is one of the most frequent in the study of squamous cell carcinoma of the oral cavity (CCEC). The clear advantage is that the model is very similar to the physiological process of malignancy. The model has clear benefits by and is suitable for applications in therapeutic research.
La carcinogénesis oral experimental inducida por el químico 4-nitroquinolina 1-óxido (4NQO) es uno de los métodos más frecuentes en el estudio del carcinoma de células escamosas de la cavidad oral (CCECO). La clara ventaja del modelo radica en el gran parecido al proceso fisiológico de la neoplasia maligna. El modelo tiene beneficios claros y es adecuado para las aplicaciones de la investigación terapéutica.
Assuntos
Animais , Ratos , Carcinoma de Células Escamosas/etiologia , Neoplasias da Língua/induzido quimicamente , Neoplasias da Língua/ultraestrutura , Neoplasias da Língua/veterinária , Neoplasias/induzido quimicamente , Neoplasias/ultraestrutura , Neoplasias Bucais/induzido quimicamente , Neoplasias Bucais/ultraestrutura , Neoplasias Bucais/veterinária , Ratos/anatomia & histologia , Ratos/lesõesRESUMO
The aim of this study was to evaluate alkylation induced genotoxicity as a result of DNA repair deficiency during 4-nitroquinoline 1-oxide (4NQO)-induced rat tonguecarcinogenesis by means of single cell gel (comet)assay. Male Wistar rats were distributed into three groups of 10 animals each and treated with 50 ppm 4NQO solution through their drinking water for 4, 12, and 20 weeks.Ten animals were used as negative control. Blood samples and oral mucosa cells collected from all animals were divided into two aliquots of 20 lL each to study basal DNA damage and DNA damage due to genotoxin sensitivity.The first aliquot was processed immediately for comet assay to assess basal DNA damage. The second aliquot was treated with a known genotoxin, methylmetanesulfonate.Significantly greater DNA damage was noticed to oral mucosa cells from 4, and 12 weeks posttreatment.Peripheral blood cells did show statistically significant differences (P\0.05) after 20 weeks-group(squamous cell carcinoma). In conclusion, alkylation induced genotoxicity as a result of DNA repair deficiency is present in oral mucosa cells following oral experimental carcinogenesis.
Assuntos
Carcinógenos/toxicidade , Carcinoma de Células Escamosas/metabolismo , Reparo do DNA/efeitos dos fármacos , Mucosa Bucal/efeitos dos fármacos , Neoplasias da Língua/metabolismo , 4-Nitroquinolina-1-Óxido/toxicidade , Administração Oral , Alquilação , Animais , Carcinoma de Células Escamosas/induzido quimicamente , Carcinoma de Células Escamosas/genética , Ensaio Cometa , DNA/genética , DNA/metabolismo , Dano ao DNA , Água Potável , Leucócitos Mononucleares/efeitos dos fármacos , Leucócitos Mononucleares/metabolismo , Masculino , Metanossulfonato de Metila/toxicidade , Mucosa Bucal/metabolismo , Mucosa Bucal/patologia , Ratos , Ratos Wistar , Fatores de Tempo , Neoplasias da Língua/induzido quimicamente , Neoplasias da Língua/genéticaRESUMO
UNLABELLED: Studies have demonstrated that flavonoid compounds of green propolis have antitumoral activity. STUDY DESIGN: Experimental study. AIMS: To evaluate the effect of a hydroalcoholic extract of green propolis (EPV) on chemically induced epithelial dysplasias in rat tongues. METHODS AND MATERIALS: DMBA was brushed on the lingual dorsum of rats 3x/week on alternate days--100 (PROP1), 200 (PROP2) and 300 mg/kg (PROP3) EPV was administered orally for 20 weeks. EPV or DMBA were replaced by their vehicles and applied as positive (TUM1 and TUM2) and negative controls (CTR1 and CTR2), respectively. The lingual epithelium was histologically analyzed and graded according a binary system and the WHO classification; the data were compared using ANOVA (*p<0.05). RESULTS: The EPV yield was 41% and the flavonoid yield was 0.95±0.44%. According to the Binary System, TUM1, TUM2 and PROP1 were considered high risk lesions, with significantly higher morphological alteration rates compared to the other groups (p<0.05), which were considered low risk lesions. Based on the WHO classification, moderate dysplasia was TUM1 and TUM2, mild dysplasia was PROP1, PROP2 and PROP3, and non-dysplastic epithelium was CTR1 and CTR2. CONCLUSION: EPV seems to play an important protective role against chemically-induced lingual carcinogenesis in rats.
Assuntos
Células Epiteliais/efeitos dos fármacos , Própole/uso terapêutico , Neoplasias da Língua/prevenção & controle , 9,10-Dimetil-1,2-benzantraceno , Animais , Carcinógenos , Transformação Celular Neoplásica , Células Epiteliais/patologia , Masculino , Lesões Pré-Cancerosas/induzido quimicamente , Lesões Pré-Cancerosas/patologia , Lesões Pré-Cancerosas/prevenção & controle , Ratos , Ratos Wistar , Índice de Gravidade de Doença , Neoplasias da Língua/induzido quimicamente , Neoplasias da Língua/patologiaRESUMO
Studies have demonstrated that flavonoid compounds of green propolis have antitumoral activity. STUDY DESIGN: Experimental study. AIMS: To evaluate the effect of a hydroalcoholic extract of green propolis (EPV) on chemically induced epithelial dysplasias in rat tongues. METHODS AND MATERIALS: DMBA was brushed on the lingual dorsum of rats 3x/week on alternate days - 100 (PROP1), 200 (PROP2) and 300 mg/kg (PROP3) EPV was administered orally for 20 weeks. EPV or DMBA were replaced by their vehicles and applied as positive (TUM1 and TUM2) and negative controls (CTR1 and CTR2), respectively. The lingual epithelium was histologically analyzed and graded according a binary system and the WHO classification; the data were compared using ANOVA (*p<0.05). RESULTS: The EPV yield was 41 percent and the flavonoid yield was 0.95±0.44 percent. According to the Binary System, TUM1, TUM2 and PROP1 were considered high risk lesions, with significantly higher morphological alteration rates compared to the other groups (p<0.05), which were considered low risk lesions. Based on the WHO classification, moderate dysplasia was TUM1 and TUM2, mild dysplasia was PROP1, PROP2 and PROP3, and non-dysplastic epithelium was CTR1 and CTR2. CONCLUSION: EPV seems to play an important protective role against chemically-induced lingual carcinogenesis in rats.
Estudos têm demonstrado que componentes hidrossolúveis da própolis verde, flavonóides, apresentam atividade antitumoral. FORMA DE ESTUDO: Estudo experimental. OBJETIVO: Avaliar o efeito do extrato hidroalcoólico de própolis verde (EPV) sobre displasias epiteliais linguais quimicamente induzidas em ratos. MATERIAIS E MÉTODOS: Neste estudo, foi pincelado DMBA (9,10-dimetil-1,2- benzatraceno) no dorso lingual de ratos 3x/semana, em dias alternados, administrado 100 (PROP1), 200 (PROP2) e 300 mg/kg (PROP3) de EPV (v.o.), durante 20 semanas. A substituição do EPV ou DMBA pelos seus veículos foi usada nos controles positivos (TUM1 e TUM2), negativos (CTR1 e CTR2), respectivamente. O epitélio lingual foi analisado histologicamente, graduado pelo Sistema Binário e classificação OMS, e os dados comparados por análise de variância (ANOVA) (p<0,05). RESULTADOS: O rendimento do EPV foi 41,43 por cento e o teor de flavonóides 0,95±0,44 por cento. Segundo o Sistema Binário, TUM1, TUM2 e PROP1 foram considerados lesões de alto risco, apresentando índices de alterações morfológicas significativamente mais elevados (p<0,05), e os demais de baixo risco. Segundo a classificação OMS, observou-se displasia moderada em TUM e TUM2, leve em PROP1, PROP2 e PROP3, e ausente em CTR1 e CTR2. Conclusão: Sugere-se que o EPV possa desempenhar um papel protetor importante durante a carcinogênese lingual quimicamente induzida em ratos. CONCLUSÃO: Sugere-se que o EPV possa desempenhar um papel protetor importante durante a carcinogênese lingual quimicamente induzida em ratos.
Assuntos
Animais , Masculino , Ratos , Células Epiteliais/efeitos dos fármacos , Própole/uso terapêutico , Neoplasias da Língua/prevenção & controle , Carcinógenos , Transformação Celular Neoplásica , Células Epiteliais/patologia , Lesões Pré-Cancerosas/induzido quimicamente , Lesões Pré-Cancerosas/patologia , Lesões Pré-Cancerosas/prevenção & controle , Ratos Wistar , Índice de Gravidade de Doença , Neoplasias da Língua/induzido quimicamente , Neoplasias da Língua/patologiaRESUMO
The aim of this study was to investigate oxidative DNA damage during 4-nitroquinoline 1-oxide (4NQO)-induced rat tongue carcinogenesis. For this purpose, male Wistar rats were distributed into three groups of 10 animals each and treated with 50 ppm 4NQO solution through their drinking water for 4, 12, and 20 weeks. Ten animals were used as negative control. The alkaline Comet assay modified with lesion-specific enzymes was used to detect single and double strand breaks, labile sites (SBs), and oxidised purines and pyrimidines. Although no histopathological abnormalities were induced in the epithelium after 4 weeks of carcinogen exposure, oxidative DNA damage was detected in the 'normal' oral epithelium. In pre-neoplastic lesions and squamous cell carcinomas induced after 12 and 20 weeks following carcinogen exposure, respectively, oxidative DNA damage was also increased (P < 0.05) when compared to negative control. In conclusion, our results suggest that oxidative DNA damage is an early event during multistep carcinogenesis assay induced by 4NQO. This kind of approach should be considered to persons with high risk of oral cancer, such as in smokers or alcohol consumers.
Assuntos
Carcinoma de Células Escamosas/induzido quimicamente , Dano ao DNA , Neoplasias da Língua/induzido quimicamente , 4-Nitroquinolina-1-Óxido , Animais , Carcinógenos , Carcinoma de Células Escamosas/patologia , Ensaio Cometa , Hiperplasia/induzido quimicamente , Hiperplasia/patologia , Masculino , Mucosa Bucal/efeitos dos fármacos , Mucosa Bucal/patologia , Oxirredução , Ratos , Ratos Wistar , Língua/efeitos dos fármacos , Língua/patologia , Neoplasias da Língua/patologiaRESUMO
BACKGROUND: The aim of this study was to investigate whether mutations in the genes H-ras and K-ras were related to the mechanism of invasion as a result of the immunoexpression of H-Ras, Ki-67, alpha-smooth muscle actin (SMA) and vascular endothelial growth factor (VEGF) during 4-nitroquinoline 1-oxide (4NQO)-induced rat tongue carcinogenesis. METHODS: Male Wistar rats were distributed into three groups of 10 animals each and treated with 50 ppm 4NQO solution through their drinking water for 4, 12 and 20 weeks. Ten animals were used as negative control. RESULTS: Although no histopathological abnormalities were induced in the epithelium after 4 weeks of carcinogen exposure, Ki-67 was overexpresssed in the 'normal' oral epithelium. In pre-neoplastic lesions at 12 weeks following carcinogen exposure, the levels of Ki-67 were increased (P < 0.05) when compared to negative control. Ki-67, alpha-SMA and VEGF were also overexpressed in squamous cell carcinomas induced after 20 weeks of treatment with 4NQO. No significant statistical differences (P > 0.05) were found in H-ras protein expression for all experimental periods evaluated that corresponded to normal oral mucosa, hyperplasia, dysplasia and squamous cell carcinomas. In the same way, no mutations in H-ras or K-ras genes were found. CONCLUSIONS: Our results support the idea that expression of Ki-67 plays a crucial role during malignant transformation being closely related to neoplastic conversion of the oral mucosa cells. However, it seems that mutations in the ras genes are not involved to experimental tongue carcinogenesis induced by 4NQO.
Assuntos
Genes ras/genética , Mutação , Invasividade Neoplásica/genética , Neoplasias Experimentais/genética , Neoplasias da Língua/genética , 4-Nitroquinolina-1-Óxido , Actinas/biossíntese , Animais , Transformação Celular Neoplásica/metabolismo , Antígeno Ki-67/biossíntese , Masculino , Neoplasias Experimentais/metabolismo , Ratos , Ratos Wistar , Neoplasias da Língua/induzido quimicamente , Neoplasias da Língua/metabolismo , Fator A de Crescimento do Endotélio Vascular/biossíntese , Proteínas ras/biossínteseRESUMO
The medium-term tongue carcinogenesis assay is a useful model for studying oral squamous cell carcinomas phase by phase. The aim of the present study was to investigate the expression of p53 by immunohistochemistry and examine the DNA sequence of exons 5, 6, 7, and 8 of Tp53 for mutations during rat tongue carcinogenesis induced by 4-nitroquinoline 1-oxide (4NQO). A total of 30 male Wistar rats were treated with 4-nitroquinoline 1-oxide in their drinking water for 4, 12, and 20 weeks at a dose of 50 ppm. Ten animals were used as negative controls. No histopathological changes in the tongue epithelia were observed in the control group or in the treatment group after 4 weeks of 4NQO. Following 12 weeks of treatment, hyperplasia as well as epithelial dysplasia was found in both mild and moderate forms. At 20 weeks, moderate and/or severe oral dysplasia and squamous cell carcinoma of the tongue were found, and the majority of animals had squamous cell carcinoma. The levels of p53 protein were increased (p < 0.05) in pre-neoplastic lesions and in squamous cell carcinomas in some of the tumor cells in squamous cell carcinomas. No mutations were found in any of the exons that were evaluated after the 4-, 12-, or 20-week treatments. Taken together, our results suggest that p53 expression may be an important event in the malignant conversion, whereas Tp53 mutations are not involved in the multi-step tongue carcinogenesis of Wistar rats induced by 4NQO.
Assuntos
4-Nitroquinolina-1-Óxido/toxicidade , Genes p53 , Mutagênicos/toxicidade , Mutação , Neoplasias da Língua/genética , Proteína Supressora de Tumor p53/genética , Animais , Testes de Carcinogenicidade , Imuno-Histoquímica , Masculino , Reação em Cadeia da Polimerase , Ratos , Ratos Wistar , Neoplasias da Língua/induzido quimicamente , Neoplasias da Língua/patologiaRESUMO
Matrix metalloproteinases (MMPs) are implicated in a wide range of physiological and pathological processes, including morphogenesis, wound healing, angiogenesis, inflammation, and cancer. The purpose of this study was to characterize the role of MMPs as depicted by the expression of MMP-2 and MMP-9 during 4-nitroquinoline 1-oxide-induced rat tongue carcinogenesis. Male Wistar rats were distributed into three groups of 10 animals each and treated with 4-nitroquinoline 1-oxide solution at 50 ppm through their drinking water for 4, 12, and 20 weeks. Ten animals were used as control group. No histopathological abnormalities were induced in the epithelium after 4 weeks of carcinogen exposure; however, immunoexpression of MMP-2 was noticed. The same picture occurred to MMP-9, in which positive expression was detected for this immunomarker. MMP-2 and MMP-9 showed positive expression either in pre-neoplastic lesions at 12 weeks following carcinogen exposure or in well-differentiated squamous cell carcinoma induced after 20 weeks of treatment with 4NQO. Taken together, our results support the belief that MMP-2 and MMP-9 play important role during malignant transformation and conversion of oral mucosa as assessed by immunohistochemistry.
Assuntos
4-Nitroquinolina-1-Óxido , Metaloproteinase 2 da Matriz/metabolismo , Metaloproteinase 9 da Matriz/metabolismo , Lesões Pré-Cancerosas/enzimologia , Lesões Pré-Cancerosas/patologia , Neoplasias da Língua/enzimologia , Animais , Citoplasma/enzimologia , Citoplasma/patologia , Imunoquímica , Masculino , Ratos , Ratos Wistar , Neoplasias da Língua/induzido quimicamente , Neoplasias da Língua/patologiaRESUMO
The Wnt/beta-catenin signaling pathway plays an important role in development, tissue homeostasis, and regeneration. Inappropriate activation of the Wnt pathway is linked to a wide range of human cancers. The purpose of this study was to characterize the Wnt/beta-catenin signaling pathway as depicted by the expression of Wnt1, Frizzled-1, Wnt5a, Frizzled-5 and beta-catenin during 4NQO-induced rat tongue carcinogenesis by immunohistochemistry. Male Wistar rats were distributed into three groups of 10 animals each and treated with 4NQO solution at 50 ppm through their drinking water for 4, 12, and 20 weeks. Ten animals were used as control group. No histopathological abnormalities were induced in the epithelium after 4 weeks of carcinogen exposure; however, an overexpression of Wnt5a was noticed when compared to control group (p<0.05). The Wnt1 showed significant differences (p<0.05) in pre-neoplastic lesions at 12 weeks following carcinogen exposure. In well-differentiated squamous cell carcinoma induced after 20 weeks of treatment with 4NQO, Wnt1 was expressed in the majority of the dysplasic cells and tumor cells. This was statistically significant (p<0.05). No significant differences (p>0.05) were found in expression of Frizzled-1, Frizzled-5 or beta-catenin following oral carcinogenesis. Taken together, our results support the belief that expression of Wnt1 and Wnt5a is related to malignant transformation and conversion of oral mucosa.
Assuntos
Carcinoma de Células Escamosas/metabolismo , Lesões Pré-Cancerosas/metabolismo , Neoplasias da Língua/metabolismo , Proteínas Wnt/metabolismo , Proteína Wnt1/metabolismo , beta Catenina/metabolismo , 4-Nitroquinolina-1-Óxido/toxicidade , Animais , Carcinógenos/toxicidade , Carcinoma de Células Escamosas/induzido quimicamente , Carcinoma de Células Escamosas/patologia , Modelos Animais de Doenças , Técnica Indireta de Fluorescência para Anticorpo , Masculino , Lesões Pré-Cancerosas/induzido quimicamente , Lesões Pré-Cancerosas/patologia , Ratos , Ratos Wistar , Transdução de Sinais/efeitos dos fármacos , Neoplasias da Língua/induzido quimicamente , Neoplasias da Língua/patologia , Proteína Wnt-5aRESUMO
This study was undertaken to investigate, by immunohistochemistry, the expression of some tumor suppressor genes such as p16, p21 and Retinoblastoma (Rb) during 4-Nitroquinoline 1-oxide induced rat tongue carcinogenesis. Male Wistar rats were distributed into three groups of 10 animals each and treated with 50 ppm 4NQO solution through their drinking water for 4, 12 or 20 weeks. Ten animals were used as negative control. Neither histopathological abnormalities were induced in the epithelium after 4 weeks of carcinogen exposure, nor statistically significant differences (p>0.05) in expression of all the tumor suppressor genes were found when compared to the negative control. However, the levels of Rb were increased (p<0.05) in pre-neoplastic lesions at 12 weeks following carcinogen exposure. In well-differentiated squamous cell carcinoma induced after 20 weeks of treatment with 4NQO, p16 and Rb were expressed in some tumor cells. Taken together, the results support the belief that the expression of Rb is closely event-related to malignant transformation and conversion of the oral mucosa, being a reliable biomarker linked to oral cancer pathogenesis.