吡柔比星膀胱内灌注预防非肌层浸润性膀胱尿路上皮癌复发的机制

Mechanism of intravesical instillation of pirarubicin for preventing recurrence of non-muscle invasive bladder cancer

目的观察膀胱内灌注吡柔比星后对正常膀胱组织和膀胱癌组织细胞凋亡的影响，探讨吡柔比星膀胱内灌注预防非肌层浸润性膀胱尿路上皮癌复发的机制。方法将40例非肌层浸润性膀胱尿路上皮癌患者随机分为3组，15例于经尿道膀胱肿瘤电切术（TUR-BT）前1h、15例于TUR—BT术前24h行膀胱内灌注（30mg吡柔比星，在膀胱内保留30min），对照组10例仅行TUR—BT术。取患者的正常膀胱组织和膀胱癌组织，以荧光显微镜观察吡柔比星的分布，原位末端标记（TUNEL）法检测细胞凋亡，免疫组化染色检测bcl-2和bax的蛋白表达。结果吡柔比星膀胱内灌注后1h，正常膀胱组织黏膜层偶见吡柔比星荧光，膀胱癌组织可见弥漫分布的吡柔比星荧光，可达肌层。24h后，在膀胱癌组织内仍可见到吡柔比星的荧光。TUNEL检测结果显示，实验组膀胱癌的凋亡指数显著高于对照组（P〈0．01）。bcl-2／bax比值与凋亡指数具有相关性。结论吡柔比星灌注化疗中可选择性作用于非肌层浸润性膀胱尿路上皮癌。通过影响膀胱癌组织bcl-2／bax表达，诱导肿瘤细胞发生凋亡，可能是吡柔比星膀胱内灌注预防非肌层浸润性膀胱尿路上皮癌复发的重要机制。

Objective To evaluate the apoptosis-inducing effect of intravesical instillation of pirarubicin （THP） on bladder cancer and normal bladder tissue, and explore the mechanism of such treatment for preventing recurrence of non-muscle invasive bladder cancer. Methods Forty patients with primary non-muscle invasive bladder cancer were treated in our hospital from January 2006 to October 2008. The patients were divided into three groups, including 15 cases treated by intravesieal instillation of THP （30 mg/50 ml, 0.5 hours） at 1 hour, 15 cases at 24 hours before transuretheral resection of bladder tumor （TUR-BT） , and 10 cases in control group who received TUR-BT only. The THP uptake of the tumor and normal bladder tissues was observed by fluorescence microscopy, the apoptosis was assessed with TUNEL staining, and immunohistochemistry was used to detect the expression of bel-2 and bax. Results Seldom fluorescence of THP in normal bladder tissues and some diffuse fluorescence reaching the muscular layer in the tumor area were observed after THP instillation at 1 hour before TUR-BT. The fluorescence of THP could still be observed in the tumor tissues at 24 hours after THP instillation. The apoptosis indexes （AI） of tumors in the chemotherapy groups were significantly higher than that in the control group （ P 〈 0. 01 ）. There was a correlation between bcl-2/bax ratio and AI. Conclusion Pirarubicin can be uptaken by bladder cancer tissue selectively and induces apoptosis of tumor cells. The changes of expression of bcl-2 and bax and decreasing of the bcl-2/bax ratio may be an important mechanism of action of the intravesical instillation of THP for preventing recurrence of non-muscle invasive bladder cancer.