大鼠结直肠腺瘤—癌序列模型的APC蛋白表达及意义

目的 探讨SD大鼠结直肠“腺瘤-癌”序列模型不同病变阶段正常组织、腺瘤和癌变组织中结肠腺瘤性息肉病基因（adenomatous polyposis coli,APC）蛋白表达水平的变化.方法 采用1,2-二甲基肼盐建立结直肠“腺瘤-癌”序列动物模型.按30mg·kg^-1体质量,每周皮下注射1次,连续注射20周.造模完成后取同时存在正常、腺瘤和癌组织的30例SD大鼠结直肠组织标本,用免疫组化染色方法检测APC蛋白的表达水平.结果 APC阳性表达率在癌、腺瘤、正常组织中均不同（P＜0.05）;APC阳性率正常组高于腺瘤组和癌变组,腺瘤组高于癌变组（P ＜0.0125）.免疫染色结果显示,在腺瘤-癌序列进展过程中,阳性细胞数与染色强度逐渐下降.结论 SD大鼠“腺瘤-癌”序列动物模型中,APC蛋白在不同阶段表达水平不同,可作为预测结直肠癌发生的早期肿瘤标志物.

The APC Gene Immunohistochemical Research of Colorectal Adenoma-carcinoma Sequence Model Tissue in SD Rats

Objective To explore APC gene changes of colorectal “adenoma - cancer” sequence model in protein expression levels of different stages of lesions in normal tissue, adenoma and colonic carcinoma tissue of SD rats. Methods colorectal “adenoma - cancer” sequence model in SD rats was established using 1,2 - dimethyl hydrazine salt. According to 30 mg · kg^-1 body mass, subcutaneous injection once a week, continu- ous injection for 20 weeks. After the completion of the establishing model, the normal tissue, adenoma and carcinoma tissues from one same rat as a sample were taken. Using immunohistochemical staining method, the expression of APC protein levels was detected. Results APC positive expression rate in normal, adenoma and carcinoma tissue were significantly different （ P 〈 0.05 ）. The APC positive rate in normal group was high- er than those in adenoma and cancer group while that in adenoma group was higher than that in cancer group （P 〈0.0125）. Immunohisto -chemical study showed that positive cells number and staining intensity gradually declined in the process of adenoma and carcinoma sequence progress. Conclusion The APC protein expression level is different at different stages in “adenoma- cancer” sequence model of SD rats which can be used as early predict tumor marker of colorectal cancer occurrence.