Abstract: Objective To explore the therapeutic effect of celecoxib on mice implanted with bladder cancer cells and its related mechanism. Methods Sixty male BALB/c nude mice were randomly divided into three groups: control group, model group and observation group. The model group and the observation group were implanted with human bladder cancer cell line 5637 to establish a mouse bladder cancer model. The mice in the observation group were treated with celecoxib, while the mice in the control group and the model group were injected with the same dose of 0.9% sodium chloride solution. After 4 weeks of treatment, the tumor tissue of model group and experimental group and normal tissue of control group were taken to detect the expression of CD4⁺, CD8⁺, and the ratio of CD4⁺/CD8⁺ in the tissues of three groups. Western blot was performed to test the positive expression of COX-2, VEGF and cPLA2.TUNEL method was used to test the apoptotic rate of bladder cancer cells in model group and observation group. Results The mice in the control group grew normally without tumor under the skin. The tumorigenesis rate of model group and observation group was 100%. The tumor mass of the model group and the observation group were (2.08±0.36)g and (1.18±0.21)g. Compared with the model group, the tumor mass of mice in the observation group decreased significantly (P＜0.05). The tumor inhibition rate of mice in the observation group was 43.33%. The levels of CD4⁺, CD4⁺/CD8⁺ in tissue of model group and observation group was significantly lower than that of control group, and the level of CD8⁺ was significantly higher than that of control group (P＜0.05). The levels of CD4⁺, CD4⁺/CD8⁺ in tumor tissue of mice in the observation group were significantly higher than those in the model group, and the level of CD8⁺ was significantly lower than that in the model group (P＜0.05). COX-2 and cPLA2 protein levels were not expressed in tissues of mice in control group, the expression of VEGF protein was positive in all three groups. The expression levels of COX-2, VEGF and cPLA2 in the observation group were significantly lower than those in the model group, and the apoptotic index was significantly higher than that in the model group (P＜0.05). Conclusions Celecoxib has a certain inhibitory effect on implanted bladder cancer in mice. Its mechanism may be related to improving the immune system level of bladder cancer mice, alleviating inflammatory reaction and inducing cancer cell apoptosis.

Key words: celecoxib, human bladder cancer cell line 5637, bladder cancer, immune cells, apoptosis