氟尿嘧啶缓释制剂抑制人结直肠癌裸鼠皮下种植瘤生长的机制研究

Mechanism of sustained-release fluorouracil suppressing the growth of human colorectal cancer in nude mice

目的探讨氟尿嘧啶缓释制剂对人结直肠癌裸鼠皮下种植瘤生长的抑制作用,进一步验证氟尿嘧啶缓释制剂是一种有效抑制肿瘤生长,副作用少的新型化疗药。方法 24只裸鼠接种人结直肠癌细胞LOVO细胞株,建立裸鼠皮下种植瘤模型,随机分为PBS对照组、5-FU注射液化疗组和缓释剂植入组,每组8只,记录三组裸鼠肿瘤大小,绘制肿瘤生长曲线,比较各组种植瘤生长情况,并HE染色观察各组肿瘤组织病理学改变,免疫组化法检测Bcl-2/Bax蛋白水平表达的变化。结果裸鼠皮下接种肿瘤细胞7d后成功致瘤。用药后肿瘤生长曲线及第30天肿瘤体积大小:PBS对照组为(3240+187)mm3、5-FU注射液化疗组为(1568+86)mm3、缓释剂植入组为(600+38)mm3,三组比较差异均有统计学意义(P均<0.05)。HE染色:缓释剂植入组相比其他组肿瘤细胞异性型明显,恶性程度明显,腺管状结构不明显,小区肿瘤细胞有凋亡明显,仅有少量坏死,肿瘤组织边界清晰,未见侵袭脂肪及肌层组织。5-FU注射液化疗组、缓释剂植入组Bcl-2蛋白表达均低于PBS对照组,Bax表达均高于PBS对照组;其中5-FU注射液化疗组Bcl-2低于缓释组,Bax高于缓释组。结论氟尿嘧啶缓释制剂对人结直肠癌裸鼠皮下种植瘤有较好的抑瘤作用,作用机制很可能通过介导下调Bcl-2和上调Bax的表达。

Objective To investigate the suppression of sustained-release fluorouracil on the growth of human colorectal cancer in nude mice, and to firther verify that sustained-release fluorouracil is an effective novel chemotherapeutic drug in suppressing tumor growth, with fewer side effects. Methods Twenty-four mice were inoculated with human colorectal cancer cell strain LOVO cells to establish tumor implanted subcutaneously nude mouse model. The mice were randomly divided into three group： the PBS group, the 5-FU group, the sustained-release fluorouracil group, with 8 mice in each group. The tumor size of the three groups of nude mice was recorded, and the tumor growth curve drawn. The implanted tumor growth was compared between the three groups. Thetumor histopathology was observed by HE staining, the expression level of Bcl-2/Bax protein was detected by immunohistochemistry. Results The subcutaneous tumor model in nude mice was successfully established after 7 d. The tumor size 30 d after treatment was （3 240±187） mm^3, （1568±86） mm^3, （600-i38） mm^3 in the PBS group, the 5-FU group, the sustained-release fluorouraeil group, respectively, with statistically significant difference between the three groups （P〈0.05）. HE staining histopathologie features： Compared with other groups, the sustained-release fluorouraeil group was found with obvious atypia and malignancy, obvious tubular structures, obvi- ous tumor cell aP0Ptosis, small amount of necrosis, clear boundary of tumor tissue, and no invasion of fat and muscle tissue. The expression of Bel-2 protein was significantly lower in the 5-FU group than the sustained-release fluoroura- oil group, followed by the PBS group. The expression of Bax were significantly higher in the 5-FU group than the sus- tained-release fluorouraeil group, followed by the PBS group. Conclusion Sustained-release fluorouracil has better antitumor effect on eolorectal cancer in subcutaneous implanted tumor in nude mice. The probable mechanism might be the down-regulation of Bel-2 expression and up-regulation of Bax expression.