多时间节点荷人胰腺癌SW1990细胞裸鼠模型的建立及其MRI表现

Establishment of the nude mouse model bearing human pancreatic adenocarcinoma in multiple timepoints and its 3.0 T MRI findings

目的研究裸鼠荷载多时间节点人胰腺癌细胞的能力，分析其MRI表现及皮下移植瘤MRI检出率。方法将人胰腺癌SW1990细胞悬液在第1天、第8天、第15天分别注射于6只裸鼠左腋窝、右腋窝、右腹股沟皮下，制成分别荷3、2、1枚瘤裸鼠各2只。3周后行MRI平扫加增强扫描，然后剥取皮下肿块行病理学检查。结果实验期间受试裸鼠全部存活，12枚肿瘤均可见，肿瘤体积与生长时间呈正相关。MRI平扫检出9枚肿瘤，增强扫描又增加检出1枚肿瘤，2枚不能检出。未检出的肿块位于右腹股沟皮下，生长时间最短，长径〈5mm。裸鼠皮下种植瘤具有类似人胰腺癌的MRI信号，有出血、坏死灶，但所有肿瘤边缘清晰，具“假包膜”征。光镜下12枚肿块均可见类似人胰腺癌的细胞。结论裸鼠可以分期皮下种植3枚人胰腺癌细胞肿瘤，并且至少存活3周，常规3．0TMRI尚不能完全检出生长时间1周、长径〈5mm的早期肿瘤。

Objective To establish nude mouse tumor models bearing human pancreatic adenocarcinoma SW1990 cells in multiple sites at different time-points and investigate the feasibility of multiple tumor-bearing in these models; then the findings and detection rate of 3.0T magnetic resonance image （MRI） in subcutaneous transplanted tumors was analyzed. Methods A total of 6 BALB/C nude mice were randomized into 3 groups （2 mice per group）. At the 1st, 8th, 15th day, the mice were injected subcutaneously with the suspension of SW1990 cells at left axilla and right axilla and right groin in sequence. Three weeks later, all the bearing-tumor mice were performed with MRI non-contrast enhanced scanning plus Gd-DTPA enhanced Scar/and the subcutaneous masses were subjected to pathological analysis. Results All the 6 nude mice were alive during the study and obvious mass was observed in every injected site. The tumor size was positively associated with the growing time. There were 9 tumors which could be detected by non- contrast enhanced MRI scanning＇ and one more tumor was detected by contrast enhanced scanning. 2 tumors were not detected, the 2 tumors were located at subcutaneous of right groin, with the shortest growing time, and the major axis of the 2 un-detected tumors was less than 5mm. Despite the MRI findings of the transplanted masses similar to that of human pancreatic adenocarcinoma with bleeding, necrosis, they presented the characteristics of a clear rim, with ＂pseudocapsule＂ sign. All the 12 masses were similar with human pancreatic adenocarcinoma under light microscope. Conclusions It is feasible to transplant human pancreatic adenocarcinoma cell at three different subcutaneous sites （injected at three different points of time） in the nude mouse, with a minimal survival time of three weeks. However, routine 3.0T Mill cannot detect the early tumors （ growing time within 1 week, major axis 〈 5 mm） .