A new liver-tumor model in the rat

Tumour growth stimulation following partial hepatectomy in mice is associated with increased upregulation of c-Met

Hepatic resection is the preferred option for curative treatment of colorectal liver metastasis (CLM). However, this is associated with significant recurrence rates in both hepatic and extrahepatic sites. The upregulation of growth factors required for liver regeneration after resection is thought to stimulate the growth of micrometastases. The current study describes temporal changes in the expression of hepatocyte growth factor receptor (c-Met), epidermal growth factor receptor (EGFR) and insulin growth factor I receptor (IGF-IR) in an orthotopic mouse model of liver resection and tumour induction. Mice underwent 70% hepatectomy and induction of liver metastases through intrasplenic injection of colorectal cancer cells. Control groups included sham-operated mice and 70% hepatectomy alone. The expression levels of liver and tumour c-Met, EGFR and IGF-IR were quantified by quantitative RT-PCR at different time points. 70% liver resection stimulates tumour growth; increases the expression of c-Met within established tumours and surrounding liver parenchyma; downregulates EGFR expression and increases IGF-IR expression within the liver parenchyma. In conclusion, we demonstrate in our mouse model that major hepatectomy stimulates engraftment and growth of CLM and that this effect is probably due to the upregulation of c-Met as a result of the liver regeneration process. Liver IGF-IR may also contribute to this phenomenon through a paracrine effect on tumour growth. This study provides support for the role of c-Met in the stimulation of tumour growth after resection possibly through the promotion of tumour cell proliferation.

Quimioembolização transarterial hepática: modelo experimental de tumor em ratos

OBJETIVO: Estabelecer um modelo de tumor no fígado de ratos para estudo do comportamento tumoral e avaliar o uso da quimiembolização transarterial. MÉTODOS: Utilizou-se oitenta e oito ratos Wistar, fêmeas, adultos, pesando entre 175- 284 g . Realizado incisão abdominal de 3 cm e implantou-se o carcinossarcoma de Walker 256 no lóbulo esquerdo do fígado. Dividiu-se em três grupos que receberam respectivamente 100x 10³ , 200x 10³ e 300x 10³ células tumorais, avaliado a pega do tumor e a sobrevida. Em outro grupo de experimento com 39 animais inoculados com tumor de Walker foi avaliado a sobrevida dos animais após infusão do 5-Flourouracil (5-FU) por via intra-peritoneal e intra-arterial. RESULTADOS: O implante do carcinossarcoma de Walker no fígado de ratos apresentou desenvolvimento de 100 %, teve um crescimento rápido e desenvolvimento de metástases tardiamente, levando os animais ao óbito entre o sétimo e décimo quinto dia. A quimiembolização transarterial é possível de ser realizada experimentalmente. O uso do 5-FU aumentou a sobrevida em comparação ao grupo controle. CONCLUSÃO: O modelo de implante do tumor de Walker no fígado de ratos é eficiente, de fácil reprodutibilidade, e sobrevida média de 9,96±0.3 dias. A quimioterapia transarterial hepática pode ser realizada experimentalmente para avaliar diversas drogas.

Implantation of VX2 carcinoma into the liver of rabbits: a comparison of three direct-injection methods

The efficacy of agarose in preventing VX2 carcinoma cell leakage was evaluated and the results were compared with two traditional methods. Forty-five rabbits were divided into 3 groups: Group 1, VX2 tumor cells were injected directly into the liver and no special procedure after removal of the needle; Group 2, the puncture site was gently compressed, using an alcoholic cotton gauze, for three minutes; Group 3, 0.2 ml of heated liquid agarose was injected to seal the aperture after injection of VX2 cells. The leakage rates were 80%, 53.3% and 6.6% for group 1, group 2 and group 3, respectively. We consider agarose is a useful material in preventing the leakage in the establishment of VX2 liver tumor models.