Genetic research on fibrosis outset and its progression in chronic hepatitis (CH) by hepatitis C virus (HCV) are limited. The lack of cytogenetic data led us to investigate the presence of micronuclei (MNi), as a sign of genomic damage. Hepatocytes of hepatic parenchyma from 62 cases diagnosed with CH associated with HCV and displaying different degrees of fibrosis (F1-F4) were analyzed. These data were compared to 15 cases without fibrosis (F0). Twelve healthy liver parenchyma samples were included as control. All samples were obtained from paraffin-embedded archival material. Micronucleated hepatocytes (MN-Heps) were analyzed through Feulgen/Fastgreen staining. Results showed that the rates of MN-Heps in the F4 group were statistically significant (p < 0.05) and higher than those in the control group. Like results were also obtained on comparing F4 with F0, F1, F2 and F3 cases. Conversely, differences were not significant (p > 0.05) on comparing F0, F1, F2, F3, one against the other, as well as individual versus control. Although chromosomal losses in CH were detected, it was shown that liver parenchyma with fibrosis in the initial stages (F1-F3) cannot be considered cytogenetically abnormal.

Grande variedade de modelos experimentais foram estabelecidos em neuro-oncologia durante as últimas décadas, a fim de estudar a biologia tumoral e a eficiciência de novas drogas e novos tratamentos em gliomas malignos humanos. Embora estes modelos estejam bem caracterizados e sejam facilmente reproduzíveis e aplicáveis, há limitações quanto ao seu uso e à resposta obtida, principalmente quando utilizados para monitorização de tratamentos. A proposta deste estudo é padronizar modelo de tumor cerebral glial experimental e detectar variáveis que possam influenciar o seu desenvolvimento. Células 9L foram inoculadas na substância branca do cérebro em 48 ratos machos Sprague-Dawley; destes, 25 animais receberam eletrodos corticais para realização de eletroencefalografia. Os animais eram avaliados diariamente por observação neurológica. Vinte e quatro ratos desenvolveram tumor - 10 animais morreram ou no pós-operatório imediato ou durante a evolução; 14 animais não desenvolveram tumor. Macroscopicamente, o tumor parecia bem delimitado; características de malignidade e extensa infiltração foram observadas à microscopia de luz; o diagnóstico foi o de astrocitoma maligno. A utilização de técnica estereotáxica e a infusão de pequeno volume de suspensão celular por um tempo longo de infusão foram considerados importantes para o bom desenvolvimento do tumor. Procedimentos que merecem atenção são: contagem precisa das células na câmara de Neubauer, agitação constante da suspensão de células a serem inoculadas e fixação precisa da profundidade de inoculação. O modelo experimental desenvolvido no presente trabalho mostrou ser de execução relativamente fácil, com custo razoável e reprodutível.

A number of experimental models have been established during the last decades in order to study tumor biology and the effects of treatment or manipulation of the microenvironment of malignant glial tumors. Even though those models have been well characterised and are, to a certain extent, easily reproducible, there are limitations as to their use and to the interpretation of the results. The aim of this study is to standardize a model of a malignant glial tumor and detect possible events able to modify its development. 9L cells were inoculated intracerebrally in 48 Sprague-Dawley rats; from these, 25 animals were also implanted with a device containing electrodes for the registration of the electroencephalogramm. Animals were daily evaluated by neurologic examination. Twenty four animals developed tumor - 10 animals died either in the immediate pos-operatory period or during evolution; 14 animals did not develop tumor. Macroscopically the tumor was well demarcated from the adjacent brain; by light microscopy the tumor exhibited malignant characteristics as well as extensive infiltration of the brain parenchyma. Diagnosis was that of a malignant astrocytoma. The use of the stereotaxic frame and care to infuse a small volume of liquid containing cells during a period of 120 seconds were the most important procedures to obtain sucess in the model. Additional care should be taken in counting cells in the Neubauer camera and in maintaining cells in constant agitation before injecting the tumor-containing solution. The model here developed was efficient besides being of low cost and of relatively easy execution.