生孢梭菌作为肿瘤基因治疗载体应用方式与动态分布

THE WAY OF APPLICATION AND DYNAMIC DISTRIBUTION OF CLOSTRIDIUM SPOROGENES AS VECTOR FOR TUMOR GENE THERAPY

目的探讨生孢梭菌在乳癌小鼠体内的应用方式与动态分布,为实体瘤治疗中生孢梭菌的具体应用提供参考。方法制备小鼠乳癌模型。取生孢梭菌的芽胞和繁殖体,以尾静脉和瘤内注射两种方式注射到乳癌小鼠体内,定期随机选取小鼠,处死后取其肝、肾、脾等重要器官以及肿瘤组织制作印片,经革兰染色后镜下观察。同时取组织匀浆进行厌氧培养,观察不同时期组织内细菌分布情况。结果生孢梭菌的繁殖体与芽胞一样可以在低氧的乳癌内部定居繁殖,且没有观察到明显的毒性。静脉注射后,生孢梭菌可以在肿瘤内大量繁殖,与瘤内注射的结果相同;与瘤内注射不同的是,各器官中有少量细菌分布,但随时间的推移很快被清除。生孢梭菌在肿瘤消退之前被进入肿瘤内部的中性粒细胞吞噬消除。结论生孢梭菌是一种靶向性好、安全性高、自限性的实体瘤治疗的靶向载体;在实体瘤的靶向治疗中,可以采用静脉注射的方式,随意采用生孢梭菌的繁殖体、芽胞或二者混合物作为载体将抗肿瘤基因定向送至肿瘤内部发挥作用。

Objective To investigate the application and dynamic distriEution of Clostridiurn sporogenes in breast-eaneer- bearing mice and provide a reference of specific use of Clostridium sporogenes in the treatment of solid tumors. Methods A breast catlcer model was created in mice. Endospofes and vegetative forms of Clostridium sporogenes were injected into the models through caudal vein and tumor. The mice were selected regularly and killed, the livers, kidneys, spleens and tumors were taken for slice, gram＇s stain, and observed microscopically. The homogenate of these tissues were collected for anaerobic culture. The bacte- rial distribution in tissue of different time was observed. Results Vegetative forms of Clostridium sporogenes-like endospores- could survive and breed inside the mionectic environment of breast cancer, with no apparent toxicity. Clostridium sporogenes could massively multiply after intravenous injection, the result was the same as iniccting into the tumor, the different from irttratumor injection was that a few bacteria could be seen in some organs, they would be cleared soon as the time lapsed. The C1ostridium sporogenes were phagocytized by neutrophils that entered the tumor before tumor regression. Conclusion Clostridium sporo- genes is a well targeting, high safety and self-limited vector in solid tumor targeted therapy. In the targeted therapy, intravenous injection of either vegetative forms or spores, or both of them, can be applied at will as a vector to play a role inside the tumor.