兔原位直肠癌的光动力治疗效应和不良反应研究

The treatment effect and adverse reactions of PDT on rabbits with rectal cancer in-situ

目的 以兔原位直肠癌为动物模型,探讨内镜光动力疗法在治疗腔道肿瘤时照光剂量、操作方法、不良反应等对其疗效的影响,为光动力疗法治疗直肠癌提供临床前依据.方法 建立20只兔VX2原位直肠癌模型,随机分为对照组、PDT低剂量组、PDT中剂量组和PDT高剂量组.血卟啉单甲醚（HMME）光敏剂于PDT前24 h静脉注射兔体内.光源采用630 nm半导体激光器.使用普通内镜和超声内镜观察肿瘤生长情况,并记录生存时间、一般状况、不良反应等.使用苏木精-伊红染色法染色并观察组织病理变化.结果 PDT后第7天,PDT低剂量组40％轻度有效;PDT中剂量组60％明显有效,20％轻度有效;PDT高剂量组20％明显有效,80％轻度有效.PDT低剂量、中剂量、高剂量组的平均生存时间分别为14、10、5d.不良反应主要表现为炎症反应、肠梗阻、肠道蠕动功能丧失以及死亡.结论 PDT剂量是影响疗效的重要因素,合适剂量的PDT对兔直肠癌有较好的消除效果.对这些问题的深入研究有助于PDT治疗直肠癌的临床应用.

Objective To evaluate the influence of dosage,operation method,adverse reaction of endoscopic photodynamic therapy （EPDT） on its therapeutic efficacy in rabbit models of in-situ rectal cancer,so as to provide preclinical basis of photodynamic therapy for rectal cancer.Methods 20 rabbits with in-situ VX2 rectal cancer were randomly divided into control group,PDT low dose group,intermediate dose group,and high dose group.At 24 h before PDT,photosensitizer （hermimether） was intravenously injected into rabbits.630 nm semiconductor laser was used as light source.The growth of the tumor was observed by conventional endoscopy and endoscopic ultrasonography,and the survival time,general conditions and adverse reactions were recorded.The histopathological changes were observed by hematoxylin-eosin staining.Results At 7 d after PDT,the total response rates of low dose,intermediate dose and high dose group respectively were 40% （slight）,80% （60% remarkable and 20% slight）,100% （20% remarkable and 80% slight）.The average survival times of the three groups were 14 d,10 d and 5 d,respectively.The main adverse reactions were inflammation,intestinal obstruction,intestinal peristalsis loss and death.Conclusions The dosage of PDT is an important factor to influence the curative effect.The appropriate dose of PDT will have a better effect on the treatment of rectal cancer.A thorough study of these problems is helpful to the clinical application of PDT in the treatment of rectal cancer.