Implantable orthotopic bladder cancer model in Wistar rats: A pilot and feasibility study

Abstract

Purpose: The implantable bladder cancer (BC) models allow the researchers to perform rapid and useful experiments for BC. We investigated the implantation success of BC cells obtained from Wistar rats (grown in vitro), into bladders of syngeneic Wistar rats, which are commonly used in the laboratories.

Methods: The Nara Bladder Tumor No.2 (NBT-II) BC cells induced with 4-hydroxybutylnitrosamine were grown with passages in Kocaeli University Center for Stem-Cell and Gene-Therapies. After urothelial denudation, 2x10⁶ NBT-II cells were then implanted into bladders of 24 female Wistar rats (aged 7-8 weeks). The rats were randomly divided into four experimental groups; three instillation groups (8 per group) and one sham-operated control group consisting of 6 rats. First, second and third instillation groups were sacrificed at days 7, 14, and 21, respectively, and, bladders were histopathologically evaluated for BC according to WHO / International Society of Urological Pathology.

Results: All tumors were pT1 (including 1 rat that prematurely died at 5th day), except one rat that died prematurely at 8th day had pT2 tumor. Implantation rates were 28.58% (2/7) in the first group, and 42.85% (3/7) in the second, for a cumulative rate of 35.71% (5/14) in these two-groups (until 14th day). Interestingly, there was no tumor in the third group, but there was an inflammatory granulation tissue.

Conclusion: Seeding NBT-II cells into bladders of Wistar rats was described, successfully tested and demonstrated in this study. This implantable BC model of Wistar rats may be improved to increase the success rate of BC cell implantation in new studies with higher number of animals.