The effect of curcumin on bladder tumor in rat model.

OBJECTIVE: Bladder cancer is the most commonly malignant tumor in the urogenital tract, only next to prostate cancer with a higher incidence in China. Curcumin is the major component of curcuma longa and has multiple biological effects including anti-tumor. This study aimed to investigate the effect of curcumin on bladder cancer. MATERIALS AND METHODS: SPF-grade Wistar rats were used for establishing bladder cancer model through injection of N-methyl-N-nitrosourea (MNU). Rats were then randomly divided into experimental, model and control group. 160 µmol/L curcumin were applied in the experimental group while model group received an equal volume of saline. General condition, morphology changes and cell cycle of bladder cancer cells were examined. Meanwhile, apoptotic proteins including Bcl-2, Bax and surviving were also measured by Western blot. RESULTS: Model rats displayed fever, hematuria, decreased food and water intake, dispersed fur, lower body mass and decreased activity. Under microscopy, the bladder wall was thickened with the cauliflower-like lesion, in which significant necrotic and hemorrhagic lesions were found. Experimental group rats improved general condition without decrease of body mass. The only minor lesion was found without significant necrosis or hemorrhage without invasion into the muscular layer. The number of G1 phase cells was increased while S phase cell number was decreased after drug intervention, suggesting suppression of G1/S transition (p < 0.05). In curcumin-treated rats, the expression of Bcl-2 and Survivin were significantly decreased while Bax protein expression was significantly elevated (p < 0.05). CONCLUSIONS: Curcumin can inhibit the growth and invasion of rat bladder cancer cells, possibly through the arresting of G1/S transition and subsequently increased apoptosis.