[A novel model for isolation of Walker's tumoral cells using the Ficoll-Hypaque gradient].

Purpose: The purpose was to evaluate a novel technique for isolation of Walker's tumoral cells using a Ficoll-Hypaque gradient and its further influence on tumor development.

Methods: Twenty male Wistar rats have been divided in 2 groups: G1= without ficoll, G2= with ficoll. Tumor was excised, homogenized and suspended in lactate ringer. A sample of the cell suspension was adjusted at a concentration of 1x10(6) cells/ml (G1). A second sample was centrifuged on a Ficoll-Hypaque gradient and the cell concentration was then adjusted (G2). Tumor was implanted by subcutaneous injection of 1.0 ml in the right armpit of rats. Tumor volume (TV) and tumor weight (TW) were compared in two groups.

Results: There were no differences between the two groups in TV (G1=17.9+/-3.8 cm3 vs. G2=17.2+/-4.4 cm3; p=0.190) and TW (G1=7.0+/-1.8 g vs. G2=7.3+/-2.8 g; p=0.569). The histological analysis showed similar patterns of infiltration by small-undifferentiated cells and necrosis in both groups. However, a mild to moderate granulocytic exudate was more frequent in the animals whose tumors derived from Ficoll-isolated cells. Hemorrhage from slight to moderate was only observed in this group.

Conclusion: A Ficoll-Hypaque gradient can provide more adequate isolation of Walker's tumor and the cell suspension obtained by this technique has lower contamination by other cell types.