title: Preconditioning methods influence tumor property in an orthotopic bladder urothelial carcinoma rat model.
abstract: Urothelial carcinoma (UC) is an extremely common type of cancer that occurs in the bladder. It has a particularly high rate of recurrence. Therefore, preclinical studies using animal models are essential to determine effective forms of treatment. In the present study, in order to establish an orthotopic bladder UC animal model with clinical relevance, the effects of preconditioning methods on properties of the developed tumor were evaluated. The bladder cavity was pretreated with phosphate-buffered saline (PBS), acid-base, trypsin (TRY) or poly (L-lysine) (PLL) and then rat UC cells (AY-27) (4×106cells) were inoculated. The results demonstrated that, two weeks later, the tumorigenic rate (88%) and tumor count (2.3 per rat) were not significantly different among the preconditioning methods, whereas tumor volume and invasion depth into bladder tissue were significantly different. Average tumor volumes were >50 mm3in the PBS and acid-base-treated groups and <10 mm3in the TRY- and PLL-treated groups. The percentage of invasive tumors (T2 or more advanced stage) was ∼75% of total tumors in the PBS- and acid-base-treated groups, whereas the percentages were reduced in the TRY- and PLL-treated groups (58 and 32%, respectively). Non-invasive tumors (Ta or T1) accounted for 54% of tumors in the PLL-treated group, which was 2-5-fold higher than the percentages in the remaining groups. Properties of the developed tumor in the rat orthotopic UC model were different depending on preconditioning methods. Therefore, different animal models suitable for a discrete preclinical examination may be established by using the appropriate preconditioning condition.
authors.affiliation: Division of Clinical Biotechnology, Center for Disease Biology and Integrative Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo 113-0033; ; Department of Integrative Physiology and Bio-Nano Medicine, National Defense Medical College, Saitama 359-8513;
authors.forename: Kozo
authors.initials: K
authors.lastname: Miyazaki
authors.affiliation: Department of Integrative Physiology and Bio-Nano Medicine, National Defense Medical College, Saitama 359-8513;
authors.forename: Yuji
authors.initials: Y
authors.lastname: Morimoto
authors.affiliation: Division of Clinical Biotechnology, Center for Disease Biology and Integrative Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo 113-0033;
authors.forename: Nobuhiro
authors.initials: N
authors.lastname: Nishiyama
authors.affiliation: Department of Urology, Tokyo Metropolitan Children's Medical Center, Tokyo 183-8561;
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Satoh
authors.affiliation: Department of Integrative Physiology and Bio-Nano Medicine, National Defense Medical College, Saitama 359-8513;
authors.forename: Masamitsu
authors.initials: M
authors.lastname: Tanaka
authors.affiliation: Department of Integrative Physiology and Bio-Nano Medicine, National Defense Medical College, Saitama 359-8513;
authors.forename: Nariyoshi
authors.initials: N
authors.lastname: Shinomiya
authors.affiliation: Department of Urology, National Defense Medical College, Saitama 359-8513, Japan.
authors.forename: Keiichi
authors.initials: K
authors.lastname: Ito
keywords: acid-base; phosphate-buffered saline; polylysine; trypsin; ultrasonography