研究肿瘤化疗后转pCH510质粒是否提高疗效，以及二者衔接是否需要特定的条件。方法：采用瘤细胞接种建立小鼠肿瘤模型：通过基因转染，观察pCH510对不同接种量所形成的小鼠肿瘤的抑制作用以及小鼠肿瘤化疗后立即进行pCH510转染的抑瘤效果；采用细胞培养技术，观察小鼠体内注射化疗药物后，其对小鼠腹腔巨噬细胞和脾淋巴细胞激活功能的影响；采用细胞计数的方法，观察化疗药物所致小鼠腹腔巨噬细胞和外周血免疫细胞数量变化的动力学；另外小鼠肿瘤化疗后第5天进行pCH510转染，观察抑瘤效果。结果：转染pCH510对不同接种量形成的小鼠肿瘤生长都有抑制作用，并呈负相关。化疗药物可使免疫细胞代谢降低，活化受阻，在化疗后第3天免疫细胞数降至最低，约10d左右恢复正常；化疗后立即连续10d转染pCH510质粒，疗效没有增强；化疗5d后，再连续15d转染pCH510质粒，则疗效明显增强。结论：化疗后转染pCH510质粒，对小鼠肿瘤治疗效果更好，但由于化疗既降低免疫细胞数量，又抑制其功能，化疗后立即转染pCH510质粒是不恰当的，并且转染治疗时间不宜过短。pCH510、化疗和化疗 pCH510三者对肿瘤不同抑制特点的比较显示化疗具有两面性，既抑瘤又捉瘤。

Objective: To investigate whether transfection with plasmid pCH510 after chemotherapy can improve therapeutic effect on tumor and whether linkage of two factors needs special conditions. Methods: Mice were inoculated with tumor cells. Inhibitory effect of transfection with pCH510 on murine tumor origined from different inoculative dose and inhibiting effect of immediate transfection pCH510 after chemotherapy on tumor were observed, respectively. By cell culture technique, the influence of chemotherapeutic drug to activation of marcrophages and lymphocytes after i.p. injection of drug was observed. By cell counting method, the kinetics of the change of number of peripheral blood immunocytes induced by administration of chemotherapeutic drug was observed. The inhibitory effect of transfection with pCH510 five days after chemotherapy on murine tumor was observed. Results: pCH510 had inhibitory effect on murine tumor from different inoculative dose and the effect negatively correlated with inoculative dose. Chemotherapeutic drug decreased number of immunocytes and suppressed their activation in vivo . After injection of drug, the number of immunocytes was the lowest on the third day and got back to normal level on the 10th day.The therapeutic effect was not improved by immediate 10-day transfection with plasmid pCH510 after chemotherapy, but was significantly improved by 15-day transfection with plasmid pCH510 after chemotherapy 5 days. Conclusion: Transfection with pCH510 after chemotherapy may acquire better effect for tumor therapy than using single factor. Chemotherapy not only decreases the number of immunocytes but also suppresses their function, so the immediate transfection with pCH510 after chemotherapy is not good strategy, and the time of treatment by transfection should not be too short. Comparison of the inhibitory effect of pCH510, chemotherapy and chemotherapy pCH510 showed that chemotherapy had a dual effect on tumor growth.

本课题受国家自然科学基金(39870763)、教育部跨世纪人才基金资助