Abstract: AIM: To optimize an orthopedic non-muscle invasive bladder cancer (NMIBC) model in nude mouse by comparing four different ways of cellular transplantation, and to evaluate the efficacy of drug by bladder instillation, so as to provide a stable and efficient animal model for the treatment of bladder cancer.  METHODS: After disruption of bladder mucosa by dilute acid-alkali or silver nitrate, T24 cells were instilled into the nude mouse bladder. T24 cells were injected directly into the bladder with mechanical injury of bladder mucosa. T24 cells were injected into the bladder wall. On the 14th day after making models, the nude mice were sacrificed. And the bladder mass and histopathological changes of tumor (including bladder) was observe to confirm the formation of orthopedic bladder cancer. The dynamic changes of orthopedic bladder cancer were observed after injecting T24 cells into the bladder wall. Gemcitabine was used to verify the applicability of the model of injecting T24 cells into the bladder wall in vivo. RESULTS: No tumor was found in the bladder after intravesical instillation of T24 cells with dilute acid-alkali or silver nitrate treatment. With mechanical injury of bladder mucosa, all nude mice had tumors after injection T24 cells. But the number of tumors varied and often occurred at multiple sites. The tumor was found in the bladder of all nude mice by injecting T24 cells into bladder wall, and there was only one tumor. The tumor showed slow linear growth within 15 days and rapid linear growth from day 18 to 31. In vivo efficacy evaluation, gemcitabine 150 mg/kg intravesical perfusion could significantly inhibit the growth of NMIBC in nude mice replicated by direct injection of T24 cells into the bladder wall, and the tumor inhibition rate was 97.1%. CONCLUSION: The orthotopic NMIBC model can not be established with the bladder mucosa injuried by dilute acid-alkali or silver nitrate treatment. The number and size of orthotopic bladder cancer are different by mechanical injury of bladder mucosa. Injection of T24 cells into the bladder wall of nude mouse can successfully establish the orthotopic NMIBC model, which can be used for the evaluation of NMIBC therapeutic drugs.

Key words: orthotopic bladder cancer model, non-muscle invasion, nude mouse, gemcitabine