Establishing a Murine Superficial Bladder Cancer Model <em>via</em> an Intravesical Cell Administration Technique

This study presents an innovative method for establishing an orthotopic murine bladder tumor model with high efficiency and precise tumor localization. After anesthetizing female C57BL/6J mice in a supine position, a 24 G intravenous needle is inserted into the bladder to evacuate its contents. A 34 G dispensing needle is then introduced through the catheter, rotated five times to create a focal injury to the bladder dome mucosa, and subsequently removed. The MB49 cell suspension is aspirated and connected to a 30 G dispensing needle, which is inserted into the bladder via the catheter. Tumor cells are injected submucosally into the bladder under pressure. This technique results in minimal trauma to the mice, a high tumor take rate, and a fixed tumor location. It is characterized by simplicity and excellent reproducibility. This model provides an ideal experimental platform for developing intravesical therapies for bladder cancer, facilitating the advancement and optimization of treatment strategies for this malignancy.