Development of dog mammary tumor xenograft in immunosuppressed Swiss albino mice.

Development and study of dog mammary tumour xenograft in immunosuppressed Swiss Albino Mice adds a new dimension in cancer research as dog tumors have many similarities with human tumors regarding progression, histopathology, molecular mechanism, immune response and therapy. Failure of the immune system to recognize and eliminate cancer cells leads to cancer progression and the fight between immune cells and cancer cells has a great role in understanding the mechanism of cancer progression and elimination. Rejection and acceptance of tumour xenograft depends on efficiency of CD4+, CD8+ and NK cell populations. In the present investigation, dog mammary tumor xenograft in cyclosporine-A and γ-irradiated, immunosuppressed Swiss Albino mice was developed and the immune cell status of graft accepted and rejected mice was assessed. It was observed that all the major immune cells (CD4+, CD8+ and NK cells) play an equal role in tumour rejection.

Histopathological evaluation of tumor necrosis and volume after cyanogenic chemotherapy

PURPOSE: To determine the percentage of tumoral necrosis and volume after cyanogenic chemotherapy. METHODS: Histopathological findings of 20 Swiss mice inoculated subcutaneously in the left abdominal wall with 0.05 ml of cell suspension containing 2.5 x 105 viable cells of the Ehrlich tumor were evaluated. The tumor response to cyanogenic chemotherapy was determined using a system that comprises two inhibition factors of tumor growth by calculating the percentage of necrosis in the tumor tissue and calculation of tumor volume in treated animals relative to that in control animals. The importance of this system has been validated by the correlation between tumor inhibition in the groups treated with the respective percentages of necrosis. RESULTS: While the control group presented an average of 13.48 ± 14.71% necrosis and average tumor volume of 16.18 ± 10.94, the treated group had an average of 42.02 ± 11.58 and 6.8 ± 3.57, respectively. The tumor inhibition was significantly associated with treatment (p=0.0189). The analysis of necrosis percentage showed a significant prognostic importance (p=0.0001). CONCLUSION: It is concluded that the effect of cyanogenic chemotherapy showed strong inhibitory action of tumor growth, as well as an increase in its area of necrosis. .

Cyclosporin safety in a simplified rat brain tumor implantation model / Segurança do tratamento com ciclosporina em um modelo pré-clínico de tumor cerebral experimental em ratos

Brain cancer is the second neurological cause of death. A simplified animal brain tumor model using W256 (carcinoma 256, Walker) cell line was developed to permit the testing of novel treatment modalities. Wistar rats had a cell tumor solution inoculated stereotactically in the basal ganglia (right subfrontal caudate). This model yielded tumor growth in 95 percent of the animals, and showed absence of extracranial metastasis and systemic infection. Survival median was 10 days. Estimated tumor volume was 17.08±6.7 mm³ on the 7th day and 67.25±19.8 mm³ on 9th day post-inoculation. Doubling time was 24.25 h. Tumor growth induced cachexia, but no hematological or biochemical alterations. This model behaved as an undifferentiated tumor and can be promising for studying tumor cell migration in the central nervous system. Dexamethasone 3.0 mg/kg/day diminished significantly survival in this model. Cyclosporine 10 mg/kg/day administration was safely tolerated.

Neoplasias encefálicas constituem a segunda causa neurológica de morte. Foi desenvolvido um modelo animal simplificado de tumor cerebral em ratos utilizando a linhagem celular W256 (carcinoma 256 de Walker) para permitir teste de novos tratamentos. Ratos Wistar foram inoculados nos gânglios da base (caudato subfrontal direito) com uma solução celular tumoral, por via estereotáxica. Este modelo demonstrou crescimento tumoral em 95 por cento dos animais inoculados com sucesso, além de mostrar ausência de metástases extracranianas e infecção sistêmica. A mediana de sobrevida dos animais foi de 10 dias. O volume tumoral estimado foi de 17,08±6,7 mm³ no sétimo dia e de 67,25±19,8 mm³ no nono dia após a inoculação. O tempo de duplicação foi estimado em 24,25 h. O crescimento tumoral induziu a caquexia, mas não houve alterações bioquímicas ou hematológicas. Esse modelo permite fácil reprodução e comporta-se como um tumor indiferenciado, mostrando potencial para estudar migração celular tumoral no sistema nervoso central. Dexametasona 3,0 mg/kg/dia reduziu significantemente a sobrevida dos animais inoculados com tumor nesse modelo. Ciclosporina 10 mg/kg/dia não teve efeito na sobrevida, sendo sua administração bem tolerada.

A murine model of xenotransplantation of human glioblastoma with imunosupression by orogastric cyclosporin / Modelo murino de xenotransplante de glioblastoma humano com imunossupressão utilizando ciclosporina orogástrica

Several animal experimental models have been used in the study of malignant gliomas. The objective of the study was to test the efficacy of a simple, reproducible and low cost animal model, using human cells of glioblastoma multiforme (GBM) xenotransplantated in subcutaneous tissue of Wistar rats, immunosuppressed with cyclosporin given by orogastric administration, controlled by nonimunosuppressed rats. The animals were sacrificed at weekly intervals and we have observed gradual growth of tumor in the immunosuppressed group. The average tumor volume throughout the experiment was 4.38 cm³ in the immunosuppressed group, and 0.27 cm³ in the control one (p<0.001). Tumors showed histopathological hallmarks of GBM and retained its glial identity verified by GFAP and vimentin immunoreaction. Immunosuppression of rats with cyclosporin was efficient in allowing the development of human glioblastoma cells in subcutaneous tissues. The model has demonstrated the maintenance of most of the histopathological characteristics of human glioblastoma in an heterotopic site and might by considered in research of molecular and proliferative pathways of malignant gliomas.

Vários modelos animais têm sido avaliados no estudo dos gliomas e até o momento nenhum pôde ser considerado ideal. O objetivo deste trabalho é verificar a eficácia de um modelo animal simples, reprodutível e de baixo custo. Utilizamos células humanas de glioblastoma multiforme (GBM) xenotransplantadas em ratos Wistar, submetidos a imunossupressão com ciclosporina administrada por via orogástrica. Células tumorais foram implantadas no tecido subcutâneo dos ratos imunossuprimidos com ciclosporina, sendo o controle feito em ratos não imunossuprimidos. Os animais foram sacrificados em intervalos semanais e foi observado crescimento progressivo do tumor no grupo imunossuprimido. A média do volume tumoral em todo o experimento foi de 4,38 cm³ no grupo imunossuprimido e 0,27 cm³ no grupo controle (p<0,001). Os tumores apresentavam características histopatológica do GBM e mantinham sua identidade glial, verificadas por imunoreação para GFAP e vimentina. A imunossupressão dos ratos com ciclosporina foi eficiente em permitir o desenvolvimento do glioblastoma no tecido subcutâneo. Uma vez que o presente modelo mantém a maioria das características histopatológicas do glioblastoma humano, ele pode ser considerado em estudos que avaliem as vias moleculares e proliferativas dos gliomas malignos.

The oophorectomy effect on Walker 256 tumor inoculated into the vagina and uterine cervix of female rats / Efeito da ooforectomia no tumor de Walker 256 inoculado em vagina e colo de útero de ratos fêmeas

PURPOSE: Verify the effect of oophorectomy on the evolution of the Walker 256 tumor inoculated into the vagina and cervix of female rats. METHODS: Ten Wistar, female rats were used, distributed into two groups with 05 animals each: Tumor group (TG): Rats inoculated with Walker 256 tumor; Oophorectomy group (OG): oophorectomized rats inoculated with Walker 256 tumor. The day before the tumor vaginal inoculation, acetic acid was inoculated into the vaginas of both groups of rats; the following day, the vaginal walls were scarified with an endocervix brush, and then Walker 256 tumor was inoculated. After 12 days, the tumor was removed together with the vagina and uterine horns for macro and microscopic analyses. The data were submitted to statistical analyses. RESULTS: There was no statistical difference between the two groups; however it was observed that the behavior of tumor growth on the OG group presented greater invasion, compromising the uterine horns. CONCLUSION: The results of the study on the GO group presented a macroscopic behavior different from the TG group, however, both of them presented similar development in terms of tumor mass.

OBJETIVO: Verificar o efeito da ooforectomia à inoculação do tumor de Walker 256 em vagina e colo de útero de ratas. MÉTODOS: Foram utilizadas 10 ratas Wistar, fêmeas, virgens, adultas, distribuídas em dois grupos de estudo com 05 animais cada: grupo tumor (GT): ratas inoculadas com tumor de Walker 256, e grupo Ooforectomia (GO): ratas ooforectomizadas e inoculadas com tumor de Walker 256. No dia anterior à inoculação vaginal do tumor, foram inoculados 0,3ml de ácido acético na vagina das ratas de ambos os grupos; no dia seguinte, foi realizada a escarificação da parede vaginal com uma escova de endocérvice e inoculado tumor de Walker 256. Após 12 dias, foi removido o tumor em bloco com vagina e cornos uterinos para análise macro e microscópica. Os dados foram submetidos à análise estatística. RESULTADOS: Não houve diferença estatística entre os dois grupos; no entanto, notou-se que o comportamento de crescimento do tumor no grupo GO apresentou maior invasividade em extensão, comprometendo cornos uterinos. CONCLUSÃO: Observou-se que o grupo GO apresentou comportamento macroscópico diferente ao grupo GT, no entanto, em termos totais de massa tumoral ambos apresentam desenvolvimento similar.

Experimental inoculation model of Walker 256 carcinoma into vagina and cervix uteri of female rats

PURPOSE: To establish an inoculation model of Walker 256 carcinoma on cervix uteri and vagina of rats. METHODS: Fifteen female rats were used, and assigned to three groups each one with five rats: group A - rats with 4x10(6) cells of Walker 256 carcinoma without acid acetic inoculation; group B - rats with 2x10(6) cells of Walker 256 carcinoma with acid acetic inoculation and group C: rats with 4x10(6) cells of Walker 256 carcinoma with acid acetic inoculation. The day before tumor cells inoculation the rats from groups B and C were anaesthetized with diethylether and 0,3 ml of acetic acid was inoculated into their vaginas. Tumor cell inoculation into the vagina and cervix was done under general anesthesia with diethylether. Then a endocervical brush was used to scrape the vaginal wall and after that 0,3 ml of the liquid containing tumor cells was inoculated on the vagina and cervix. For the tumor analysis, animals were euthanized at day 12 following tumor cell implantation by an excessive inhalation of diethylether. Tumor was resected entirely and weighed and the tumors were then sectioned and counter stained with hematoxylin and eosin for histopathologic evaluation. It was also calculated the percentage of tumor equivalent to the body weight by the formula: P= tumor weight / body weight x 100. Data were analyzed by one-way analysis of variance - ANOVA. P values < 0.05 were taken to indicate statistical significance. RESULTS: Implantation and growth on GB and GC was 100 percent and on GA 20 percent. There was no statistical difference between GB and GC averages. CONCLUSION: According to the methods used, the Walker 256 carcinoma inoculation model into vagina and cervix have an implantation and growth rate of 100 percent when associated with previous acid acetic inoculation and there is no behavioral difference between using 2x10(6) or 4x10(6) cells on its inoculation.

OBJETIVO: Estabelecer um modelo de inoculação de Tumor de Walker 256 em vagina e colo de útero de ratas. MÉTODOS: Foram utilizadas 15 ratas fêmeas, virgens, adultas, pesando entre 200-250g, distribuídas em três grupos de estudo com cinco animais cada: grupo A (GA): ratas com tumor de Walker 256 em concentração de 4x10(6) sem ácido acético; grupo B (GB): ratas com tumor de Walker 256 em concentração de 2x10(6) células com ácido acético; grupo C (GC): ratas com tumor de Walker 256 em concentração de 4x10(6) células com ácido acético. No dia anterior à inoculação do tumor, foi realizada a inoculação de 0,3 ml de ácido acético a 10 por cento na vagina das ratas de GB e GC; no dia seguinte, tanto estas como as ratas do grupo GA foram anestesiadas, feita a escarificação da parede vaginal com uma escova de endocérvice e inoculado 0,3ml de tumor na concentração de 4x10(6) células nos grupos GA e GC e 2x10(6) células no grupo GB. Após 12 dias, foi realizada a eutanásia e removido o tumor em bloco com vagina e cornos uterinos para análise, sendo pesado e averiguado seu volume e calculado as relações entre o seu peso e o peso final da rata e o seu volume e o peso final da rata. Os dados foram colhidos e submetidos à análise estatística pelo método ANOVA (um critério). RESULTADOS: A pega em GB e GC foi 100 por cento e em GA 20 por cento. Não houve diferença estatística entre as médias obtidas entre GB e GC. CONCLUSÃO: De acordo com a metodologia utilizada, o modelo de tumor de Walker 256 na vagina apresenta pega de 100 por cento quando associado a ácido acético e não há diferença de comportamento com a inoculação de 4x10(6)ou 2x10(6) células.

Effects of acetylsalicylic acid and acetic acid solutions on VX2 liver carcinoma in rabbits: in vivo analysis

PURPOSE: To analyze, in vitro, the effects of acetylsalicylic acid (aspirin) and acetic acid solutions on VX2 carcinoma cells in the liver of rabbits with VX2 hepatic tumors; to determine the histolytic and anatomopathological characteristics of the solutions; and to evaluate the eventual biochemical and hepatic changes. METHODS: A total of 48 rabbits were evaluated. The animals were randomized into two groups, protocol 3 (study group) and protocol 4 (controls), and each group was then subdivided into 3 subgroups. Four days after implantation of the tumor in the liver, median laparotomy was performed with a 0.4-ml injection of a solution of either aspirin (5.0 percent), acetic acid (5.0 percent) or saline. The animals were sacrificed after 24 hours (protocol 3) or after 11 days (protocol 4). Body weight, clinical evolution and biochemical levels, as well as the abdominal and thoracic cavities, were evaluated, and liver microscopy was performed. RESULTS: No changes in clinical evolution, body weight or biochemical levels were reported. However, an increase in alkaline phosphatase was observed in protocol 4 (controls). The tumor was eliminated in both protocols. CONCLUSION: Acetylsalicylic acid and acetic acid solutions cause the destruction of experimental hepatic tumors.

OBJETIVO: Analisar os efeitos das soluções de aspirina e de ácido acético, in vivo, em fígado de coelhos portadores de tumor hepático VX2, verificando o efeito histolítico e anatomo-patológico das soluções e eventuais alterações bioquímicas hepáticas. MÉTODOS: Utilizou-se 48 coelhos, divididos em 2 protocolos experimentais(3 e 4), subdivididos em 3 grupos cada. Após 4 dias da implantação do tumor no fígado, procedeu-se a laparotomia mediana, com injeção de 0,4 ml da solução de aspirina (5,0 por cento), de ácido acético (5,0 por cento) e solução salina; o sacrifício ocorreu apos 24 horas (protocolo 3) e 11 dias (protocolo 4); avaliou-se o peso, evolução clinica, dosagens bioquímicas, cavidade abdominal e torácica e microscopia do fígado. RESULTADOS: Não foram observadas alterações na evolução clinica, peso e nas dosagens bioquímicas, apenas elevação da fosfatase alcalina no grupo controle do protocolo 4. Observamos desaparecimento do tumor em ambos os protocolos. CONCLUSÃO: As soluções de ácido acético e ácido acetilsalicílico acarretam destruição do tumor hepático experimental.