Development of the Single Nodular VX-2 Carcinoma Model in Rabbit Liver: Tissue Chip Implantation under Ultrasonographic Guidance

ABSTRACT

PURPOSE: To implant tissue chips in New Zealand rabbits, and thus redurce the frequency with which scattered VX2 carcinoma nodules and early metastasis develop in these animals. MATERIALS AND METHODS: VX2-carcinoma tissue chips of two different sizes were implanted under ultrasonographic guidance. In each of 12 New Zealand rabbits (group 1), there 1-mm tissue chips were implanted in the liver using an 18-gauge needle, and in the same way, one 3-mm chip with an added gelfoam pellet was implanted in the proximal lumen of the liver of each of ten other New Zealand rabbits (group 2). Three weeks after implantation, the animals underwent dvalphase CT scanning and were sacrificed, and the Number and size of tumor nodules, and metastasis were evaluated either macro-or microscopically. RESULTS: In ten rabbits in group I, a total of 21 nodules (16 in the liver, 5 in the peritoneal wall) were observed, which in nine rabbits in group 2, a total of ten nodules-all in the liver-were present. CT scans depicted tumor nodules in 50% of group-I rabbits, and in 29% those in group 2. Mean tumor diameter was 12 +/-9 mm in group 1 and 6.4 +/-3 mm in group 2. Histologic examination indicated the presence of nodular VX2 carcinoma, with varying degrees of central necrosis, a feature more prominent in group 2. CONCLUSION: To provide a well-localized tumor nodule in rabbit liver, tissue chip implantation of VX2 carcinoma, especially with added gelfoam, is a good alternative to intraparenchymal injection of tumor suspension.